LABORATORY AUDIT OF BENIGN OROFACIAL TUMOURS AT … · Nyeri, Meru, Kenyatta National hospital, Voi, Kericho and Homa Bay. The total number of The total number of records retrieved

LABORATORY AUDIT OF BENIGN OROFACIAL TUMOURS AT UNIVERSITY OF

NAIROBI DENTAL HOSPITAL OVER A FIVE YEAR PERIOD, (2008-2012).

INVESTIGATOR:

KHANBHAI FATEMA JUZER

V28/35908/2010

BDS LEVEL III

A community dentistry research project report submitted in partial fulfillment of

requirements for the award of the degree of Bachelor of Bachelor of Dental

Surgery(BDS) at the University of Nairobi.

2013

ii

DECLARATION

I, Fatema Khanbhai, declare that this research proposal is my own original work and has never

been submitted for any other degree or examination at this or any other University.

Signature…………………………………… Date………………………………

iii

APPROVAL

This project report has been submitted for examination with our approval as University of

Nairobi supervisors:

SUPERVISORS

PROF.FRANCIS G.MACIGO, BDS, MPH, PGD-STI (UON)

PUBLIC HEALTH SPECIALIST AND ASSOCIATE PROFESSOR OF COMMUNITY AND

PREVENTIVE DENTISTRY, DEPARTMENT OF PERIODONTOLOGY/ COMMUNITY

AND PREVENTIVE DENTISTRY, SCHOOL OF DENTAL SCIENCES, COLLEGE OF

HEALTH SCIENCES, UNIVERSITY OF NAIROBI.

Signature ……………………………….. Date ……………………

DR.ELIZABETH DIMBA (BDS –NBI, PHD-NORWAY)

SENIOR LECTURER,

DEPARTMENT OF ORAL AND MAXILLOFACIAL SURGERY ORAL PATHOLOGY AND

ORAL MEDICINE, SCHOOL OF DENTAL SCIENCES, COLLEGE OF HEALTH

SCIENCES,

UNIVERSITY OF NAIROBI

Signature ……………………………….. Date ……………………..

iv

DEDICATION

I dedicate this research to my grandparents, they will always be missed, my parents and my

brother for always giving me the support and strength to work hard.

v

ACKNOWLEDGEMENTS:

I wish to thank my supervisors Prof.Francis Macigo and Dr. Dimba for their assistance,

insightful comments and creating time for review meetings in the process of the completion of

this project.

Special thanks to Desmond for helping me during data analysis. To my dad Mr. Juzer Khanbhai,

mum Mrs. Naqiya. Juzer and brother Hussein Khanbhai, you have always been there for me.

Thank you.

vi

TABLE OF CONTENTS

Contents

DECLARATION ........................................................................................................................................................ ii

APPROVAL ............................................................................................................................................................ iii

DEDICATION ......................................................................................................................................................... iv

ACKNOWLEDGEMENTS: ......................................................................................................................................... v

TABLE OF CONTENTS ............................................................................................................................................. vi

LIST OF FIGURES .................................................................................................................................................. viii

LIST OF TABLES ................................................................................................................................................... viii

ABBREVIATIONS ................................................................................................................................................... ix

ABSTRACT .............................................................................................................................................................. 1

CHAPTER1: INTRODUCTION ................................................................................................................................... 3

CHAPTER 2: LITERATURE REVIEW ........................................................................................................................... 4

2.1: HISTOLOGICAL CLASSIFICATION OF BENIGN TUMOURS ............................................................. 4

2.2: ETIOLOGY AND EPIDEMIOLOGY .......................................................................................................... 7

2.3: MANAGEMENT AND TREATMENT MODALITIES; ............................................................................. 7

CHAPTER 3: STATEMENT OF THE PROBLEM, JUSTIFICATION AND OBJECTIVES....................................................... 9

3.1: Statement of the problem: ............................................................................................................................. 9

3.2: Study justification: ........................................................................................................................................ 9

3.3: Objectives: ..................................................................................................................................................... 9

3.3.1: General: ....................................................................................................................................................... 9

3.3.2: Specific: ........................................................................................................................................................ 9

3.4: Variables: ...................................................................................................................................................... 9

CHAPTER 4: STUDY METHODOLOGY .................................................................................................................... 11

vii

4.1: Study area: .................................................................................................................................................... 11

4.2: Study population: ........................................................................................................................................ 11

4.3: Study design: ............................................................................................................................................... 11

4.4: Sample size determination: ......................................................................................................................... 11

4.5: Sampling: ..................................................................................................................................................... 11

4.6: Inclusion and exclusion criteria: .................................................................................................................... 11

4.6.1: Inclusion criteria: ....................................................................................................................................... 11

4.6.2: Exclusion criteria: ....................................................................................................................................... 11

4.7: Data collection instruments and technique: ................................................................................................ 12

4.8: Problems anticipated ................................................................................................................................... 12

4.9: Data analyses and presentation: .................................................................................................................. 12

4.10: Ethical consideration: ................................................................................................................................ 12

4.11: Study benefits: ........................................................................................................................................... 13

CHAPTER 5: RESULTS ........................................................................................................................................... 14

CHAPTER 6: DISCUSSION, CONCLUSIONS AND RECOMMENDATION .................................................................... 23

6.1: DISCUSSIONS ................................................................................................................................................ 23

6.2: CONCLUSION: ............................................................................................................................................... 24

6.3: LIMITATION .................................................................................................................................................. 24

6.4: RECOMMENDATION ..................................................................................................................................... 24

REFERENCES:........................................................................................................................................................ 25

APPENDIX 1 ......................................................................................................................................................... 27

APPENDIX 2 ......................................................................................................................................................... 29

viii

LIST OF FIGURES

Figure 1: graph on age distribution

Figure 2 : Pie chart showing the gender distribution of benign tumors

Figure 3:pie showing histologic distribution of benign tumours

Figure 4: pie chart showing the distribution of odontogenic tumours

Figure 5: gross specimen of an ameloblast

Figure 6: pre-treatment duration

LIST OF TABLES

Table 1:gender and tumour distribution

Table 2: histologic subtypes of epithelial tumours

Table 3: mesenchymal odontogenic tumours

Table 4: mixed odontogenic tumours

Table 5: non-odontogenic tumours

Table 6: non-odontogenic subtypes

Table 7: site distribution

ix

ABBREVIATIONS

UON University of Nairobi

UONDH University of Nairobi Dental Hospital

KNH Kenyatta National Hospital

BOT Benign orofacial tumors

1

ABSTRACT

Background: Benign tumors can cause serious aesthetic disturbances, difficulty in chewing

organ damage and furthermore some have potential for malignant transformation. Due to the

morbidity caused by these tumors and challenges in management, particularly in developing

countries, understanding of sociodemographic and clinicopathological features is essential. In

Kenya there is very little information on these tumors.

Objective: To describe the socio-demographic and clinico-pathological features of benign

orofacial tumors among patients who visited University of Nairobi Dental Hospital from 2008-

2012.

Study design: This study was a descriptive cross sectional study.

Setting: The study was conducted at the University of Nairobi dental hospital histopathological

laboratory.

Data collection: Laboratory records of all patients diagnosed with oral tumors was retrieved and

examined. The data which was collected from each record included the prevalence, age, site of

lesion and the time taken before patient seeks treatment. The data was analyzed and results

presented in the form of text, tables, graphs and pie charts.

Results: Records were retrieved from the histopathology laboratory from the year 2008-

2012.These records were from many centers in Kenya, including from Machakos, Nakuru,

Nyeri, Meru, Kenyatta National hospital, Voi, Kericho and Homa Bay. The total number of

records retrieved and studied for the five year period was 755. The total number of benign

tumours were 325(43.1%) of the total while the rest 430 (56.9%) were malignant.

Of the 325 benign tumours reviewed, 184 (56.6%) were odontogenic while 141 (43.4%) were

non-odontogenic. Amongst the odontogenic, epithelial tumours (86.4%) were the most common,

while for the non-odontogenic, epithelial soft tissue tumours (44.0%) were the most common.

The commonest non-odontogenic tumour was the pleomorphic salivary adenoma (28.9%).

The mandible (44.3%) and the maxilla (12.5%) were the most common site of occurrence of

benign tumours. Patients sought treatment after 2 years.

Conclusion: From this study, it can be concluded that there is almost equal prevalence of benign

tumours in the orofacial area as the malignant tumours. They were more common in young

people from the 2nd

to 4th

decade and affected the females more than the males. The odontogenic

tumours(56.6%) were more common, while the non-odontogenic were (43.4%).Most patients

had the treatment done after 2 years and the most affected site was the mandible and maxillae.

Recommendation: Primary health workers should be better trained to diagnose and refer oral

tumours.

2

Communities should be educated on these lesions for them to seek treatment as early as possible,

so as to improve the prognosis

3

CHAPTER1: INTRODUCTION

A tumor is an abnormal mass of tissue growth of which is excessive and uncoordinated with that

of normal tissues (1).

Benign orofacial tumors are tumors that occur in the orofacial region, this includes the lip,

tongue, gingival, alveolus, floor of the mouth, palate, buccal mucosa, mandible and the maxilla

(2). It is a mass of cells that lacks the ability to invade neighboring tissue or metastasize, has a

slower growth rate and cells are well differentiated.

The growth of benign tumors produce a ‘mass effect’ that can compress tissue and may cause

nerve damage leading too parasthesia, reduction in blood supply to an area in the body leading to

tissue death (necrosis) and organ damage. When they are large enough they cause intraoral and

facial asymmetry affecting the aesthetics of the patient. They also cause displacement of teeth

and lead to malocclusion which causes chewing difficulties. Patients with extremely large

tumors may be at increased risk of secondary bone fractures due increased bone resorption and

subsequent bone thinning (3). Some have the capacity for malignant transformation.

Benign orofacial tumors are not well studied in Kenya and thus there is very little information on

it. The information on benign orofacial tumors is from research done in different parts of the

world and not in Kenya. This study will focus on the benign orofacial tumors that occur in

Kenyan population. It will also give baseline information on the tumors for advanced studies to

be conducted.

4

CHAPTER 2: LITERATURE REVIEW

Benign tumors are usually well differentiated and closely resemble the tissue of origin. They

grow slowly and do not metastasize. There are many harmful effects if their growth compresses

adjacent tissues. Radiographically they form well defined radioluscency.

2.1: HISTOLOGICAL CLASSIFICATION OF BENIGN TUMOURS

Classification of tumors in the orofacial region is cumbersome and complex because of varied

types of tissues in this region and their different growth characteristics. As a result, many have

emerged and simplest approach is to group them into:

Odontogenic tumors

Non-odontogenic tumors (4)

The classification is further sub classified according to World Health Organization as shown in

appendix 1(5).

The most frequently occurring tumours reported in various African countries include

ameloblastoma, adenomatoid odontogenic tumor, calcifying epithelial odontogenic tumor,

ameloblastic fibroma, odontogenic myxoma, odontoma, and giant cell granuloma and

pleomorphic adenoma (26,27,28).

AMELOBLASTOMA

This is a neoplasm of odontogenic epithelium. It is the most common and usually presents

between the third and fifth decades of life. Although it is a benign tumor, it exhibits aggressive

behavior, being locally invasive. It is capable of metastasis to the lungs. In its clinical behavior,

it is typically asymptomatic. Most cases appear as multilocular cysts radiographically. The most

common site is the posterior mandible. Ameloblastomas can be further classified into solid,

cystic or peripheral according to their clinical characteristics. The histological categorization is

as follows: desmoplastic, granular cell, basal cell, plexiform, follicular, and acanthomatous (6).

They are treated by excision with a wide margin of normal tissue. Maxillary ameloblastoma can

invade the cranial base and have the potential of being lethal (7).

5

ADENOMATOID ODONTOGENIC TUMOUR

It is an odontogenic tumor arising from the enamel organ or dental lamina (8).They are

uncommon, completely benign and probably a hamartoma. Clinically adenomatoid odontogenic

tumor is found either in late adolescence or young adulthood between ages 15-20. Females are

twice as frequently affected as males and it commonly occurs in the anterior maxilla.

Radiographically it appears as a unilocular dentigurous cyst (9). It is treated by enucleation (10).

CALCIFYING EPITHELIAL ODONTOGENIC TUMOUR

Rare neoplasm of odontogenic epithelium, which presents between ages 40-70. Histologically it

has many bizarre pleomorphic and hyperchromatic nuclei and formation of amyloid like

material. It’s a solid tumor, with mixed radioluscency (with both radioluscency and radio

opacity). Most commonly forms in posterior mandible. Locally invasive but does not

metastasize. It is treated by excision (11).

CALCIFYING ODONTOGENIC TUMOUR

This rare tumor mainly affects young adults and involves the alveolar process of either jaw, close

to the roots of erupted teeth. Radiographically it appears unilocular often undistinguishable from

non-neoplastic jaw cysts.

Calcification in the cysts wall may suggest the diagnosis forms at any site in alveolar ridge,

usually posteriorly, occasionally forms in soft tissues of the gingival. Histological presence of

ghost and ameloblastic like cells confirms the diagnosis. Usually responds to enucleation. (12).

AMELOBLASTIC FIBROMA

It is rare but very important as a relatively common and sometimes destructive odontogenic

tumor in the young. It’s a solid lesion but appears as unilocular or multilocular radioluscency. It

is treated by excising the tumor with a small soft tissue margin. It can undergo malignant change

(13).

ODONTOGENIC MYXOMA

The odontogenic myxoma is an uncommon benign odontogenic tumor arising from embryonic

connective tissue associated with tooth formation (14). As a myxoma, this tumor consists mainly

of spindle shaped cells and scattered collagen fibers distributed through a loose, mucoid material

6

(15). It usually occurs in young adults. They are benign but prone to recurrence. On radiographs

it forms as multilocular, sometimes soap bubble radioluscency. The most common site is

posterior mandible and it is treated by excision (16).

CEMENTOBLASTOMA

It is a relatively a rare benign neoplasm of the cementum of the teeth. It is derived from

ectomesenchyme of odontogenic origin (17). Less than 0.69%–8% of all odontogenic tumors that

usually is seen in young adults. Radiographically it appears radiopaque with narrow lucent rim.

Most commonly at the apex of a vital lower first molar. It is treated by surgical excision of the

lesion and depending upon the clinical circumstances; this may or may not involve removal of

the involved tooth. With incomplete removal, recurrence is common; some surgeons advocate

curettage after extraction to decrease the overall rate of recurrence (18).

ODONTOMA

The odontoma is a hamartoma (19) of odontogenic origin (20).Usually found between ages 10-

20 years. Develops like surrounding teeth with initial radiolucent phase, intermediate stage of

mixed radioluscency, finally densely radiopaque. May be compound (many small teeth) or

complex (disordered mass of dental hard tissue) (21). The most common sites are anterior

maxilla and posterior mandible. They are treated by enucleation (22).

PLEOMORPHIC ADENOMA

They account for about 75% of parotid gland tumors and arise mainly from duct epithelium or

myoepithelial cells. Histologically it has an incomplete capsule, sheets or strands of dark

staining epithelial cells. It presents with squamous metaplasia and foci of keratin myxoid tissue.

Growth of pleomorphic adenoma is slow and may take several years to reach an inch in

diameter. They form rubbery often lobulated swellings. It is treated by wide excision (23).

SQUAMOUS CELL PAPILLOMA

A Squamous cell papilloma is a generally benign papilloma that arises from the stratified

squamous epithelium of the skin, lip, oral cavity, tongue, pharynx, larynx, esophagus.Squamous

cell papillomas are a result of infection with human papillomavirus (HPV) (24,25).

Papillomas mainly affect adults and have a distinctive, clinically recognizable cauliflower like or

structure with finger like process.

7

Histologically the papillae consist of stratified squamous epithelium supported by a vascular

connective tissue core. Most keratinized and so appear white. While most cases require no

treatment, therapy options include cryotherapy, application of a topical salicylic acid compound,

surgical excision and laser ablation (26).

2.2: ETIOLOGY AND EPIDEMIOLOGY

Etiology of benign orofacial tumors include: environmental toxins such as exposure to radiation,

genetics, diet, tobacco, stress and local trauma or injury (2).

Benign orofacial tumors are not well studied in Kenya and thus there very little information on it.

However an audit of oral disease at Nairobi centre, 2000-2004 by Dr.Dimba et al found out that

benign tumors mean age(29.93- 18.27 years) peaked in the third decade and tended to affect men

at younger age. The most common benign tumor was the ameloblastoma (50.23%) which

predominantly affected the mandible and also occurred in male patients at younger age (27).

Another study was done in Libya that analyzed the incidence of benign tumors. Amongst the

total benign tumors the keratocystic odontogenic tumor (35%) was the most common

odontogenic tumor. Among the non-odontogenic tumors, fibrous and adipose origin was 33%,

bone tumors 20%, cases of vascular origin 14% and neurogenic 7.1% (28).

A 6 year prospective study on orofacial tumors in Ghana recorded benign tumors to be common

in men aged 40-70 years and 11-20 years in female patients. Results showed 15% as

odontogenic, 26 as non-odontogenic in relation to the total number of tumors and tumor like

lesions (29).

The annual incidence rates per million for ameloblastomas are 1.96, 1.20, 0.18 and 0.44 for black

males, black females, white males and white females respectively (30). Ameloblastomas account

for about one percent of all oral tumors (31) and about 18% of odontogenic tumors (32). Men

and women tend to be equally affected, although women tend to be 4 years younger than men

when tumors first occur and tumors appear to be larger in females (33).

2.3: MANAGEMENT AND TREATMENT MODALITIES;

Most BOT are managed by enucleation/excision and they tend to respond to treatment without

recurrence. Some of the tumors such as giant cell granulomas are treated by curettage and

requires second operation at times.

ENUCLEATION:

It is a general surgical technique that is done by surgical removal of a mass without cutting into

or dissecting it (34).

8

CURETTAGE:

It is a medical procedure that uses a curette to remove tissue by scraping or scooping (35).

There is scanty information on benign orofacial tumours in Kenya and hence this study.

9

CHAPTER 3: STATEMENT OF THE PROBLEM,

JUSTIFICATION AND OBJECTIVES

3.1: Statement of the problem:

Benign tumors contribute considerably to the disease burden in the orofacial region. Patients

tend to present late, with complications. They cause a mass effect that can compress tissue and

may cause nerve damage, reduction in blood supply to an area of the body and organ damage. It

also affects the aesthetic of a person, causes bone deposition and resorption at the tumor site and

lastly the benign tumor could metastasize to a malignant tumor. Thus this study on BOT is

important.

3.2: Study justification:

Benign orofacial tumors are a poorly studied are in Kenya. There is therefore the need to audit

and determine the clinicopathological and sociodemographic features of it, so as to facilitate the

development of management protocols and create awareness for early detection and treatment.

3.3: Objectives:

3.3.1: General:

To describe the sociodemographic and clinicopathological features of BOT in patients who

visited UONDH from 2008 to 2012

3.3.2: Specific:

1. To determine the percentage of benign oral tumors relative to all tumors diagnosed.

2. To determine the frequency of each type of benign oral tumor in relation to all benign tumors.

3. To describe the age and gender distribution of BOT

4. To determine the site of occurrence

5. To determine the time taken before patient seeks treatment.

3.4: Variables:

Dependant variables:

Benign oral tumors

10

Site of occurrence

Independent variables:

Age

Gender

Duration since the tumor was first observed

11

CHAPTER 4: STUDY METHODOLOGY

4.1: Study area:

The study will be carried out at the UONDH histopathology laboratory. The hospital is located

about 3 kilometers from the central business district of the capital city of Nairobi opposite

Nairobi hospital. UONDH is a university teaching hospital offering training to students taking

courses in the dental school of dental sciences and includes both under- and post- graduate

students. It has major and minor operating theatres and one surgical ward capable of hosting 9

patients at a time. It’s a major referral centre and it is currently the leading referral and training

dental hospital in Kenya. It therefore provides comprehensive dental services to the population

within Nairobi and its environs as well as serving as a referral hospital for many patients from

other parts of the country.

4.2: Study population:

The study will include all patients diagnosed with any type of benign oral tumor at UONDH

histopathology lab between 2008-2012.

4.3: Study design:

This is going to be a descriptive cross-sectional, done by reviewing of records of patients

samples examined at UONDH between 2008-2012.

4.4: Sample size determination:

Based on previous reports, it is estimated that around 184 records of patients with BOT will be

available for this study covering the 5 year period.

4.5: Sampling:

All the clinical records of patients seen at the oral pathology lab at the UONDH from 2008-2012,

will be included in the study.

4.6: Inclusion and exclusion criteria:

4.6.1: Inclusion criteria:

Patients diagnosed with benign orofacial tumors and treated at the UONDH between 2008-2012

4.6.2: Exclusion criteria:

12

Incomplete records

Unclear records

Records of cases not seen within specific time frame

4.7: Data collection instruments and technique:

The records were retrieved with the assistance of the laboratory technologist in charge of

histopathology laboratory. The investigator examined the records for the variables of interest of

the study and recorded them in a record form (appendix 1). The data collected included the age,

gender, type of tumor (whether benign or malignant), type of benign tumor, site of tumor and the

time taken before patient sought treatment.

4.8: Problems anticipated

Some patients who are diagnosed at the UONDH had their treatment at other hospitals.

The specimens received were from different doctors and different cities thus there was improper

history written in the records.

Lack of important information due to improper record keeping i.e. incomplete clinical notes and

missing files.

4.9: Data analyses and presentation:

The data collected was analyzed using computer aided using SPSS version 17. The data is

described in terms of percentages and frequencies and presented in the form of bar graphs and

pie charts.

4.10: Ethical consideration:

Permission will be sought from University of Nairobi dental hospital administration to carry out

the study. Research proposal will be submitted to the University of Nairobi/Kenyatta national

hospital research ethics and standard committee for approval. All information collected will be

treated with confidentiality and will be used for research purposes only.

13

4.11: Study benefits:

The study gave out information on BOT amongst the Kenyan population. The information on the

prevalence, age and gender distribution.

The findings of the study will be used as baseline data in any subsequent research on the same

topic in future on the etiology, genes involved etc.

The results of the study will be submitted as part of the fulfillment of a Bachelor of Dental

Surgery (BDS) degree of the University of Nairobi.

14

CHAPTER 5: RESULTS

Records were retrieved from the histopathology lab between the year 2008-2012.These records

were from many centers in Kenya, including Machakos, Nakuru, Nyeri, Meru, Kenyatta National

hospital, Voi, Kericho and Homa Bay.

The patients presented with pain, swelling, mobile teeth, tongue fixation, asymmetry, loss of

hearing, enlargement of tongue, altered speech, dysphagia, parasthesia and lymphadenopathy.

TYPE OF TUMOR:

The total number of tumours reported between 2008 and 2012 were 755.

Out of the 755: 382 (50.5%) were females and 373 (49.5%) were males.

The total number of benign tumours were 325(43.1%) while malignant were 430 (56.9%).

AGE AND GENDER DISTRIBUTION OF BENIGN OROFACIAL TUMOURS:

Benign tumours were common in the 3rd

to 4th decade of life.(figure 1)

Figure 1: Age and gender distribution of benign tumours.

15

The oldest patient being 95years old while the youngest was 10 days old. (Figure 1)

Mean age 31.99±17.67

GENDER DISTRIBUTION OF BENIGN OROFACIAL TUMOURS:

Of the 325 benign tumours 157(48.4%) were males while 168 (51.6%) were female giving a male to

female ratio of 1:1.1 (figure 2).

Figure 2 : Pie chart showing the gender distribution of benign tumors

51.6%

48.4%

16

DISTRIBUTION OF BENIGN TUMOURS BY YEAR REPORTED:

Table 1:gender and tumour distribution

The highest numbers of the benign tumours were seen in 2011. This was due an increased number of

specimens received to the laboratory in that year and it was not so clear on why the increased number of

specimens.

DISTRIBUTION OF BENIGN TUMOURS BY HISTOLOGIC TYPE:

The total number of benign tumors was 325.

Figure 3: histologic distribution of benign tumours

YEAR BENIGN TUMOURS

Number of benign

tumours

Percentage of benign

tumours

2008 55 16.9%

2009 53 16.3%

2010 56 17.3%

2011 110 33.8%

2012 51 15.7%

Total 325 100%

17

Of the 325 benign tumours reviewed 184 (56.6%) were odontogenic, 141 (43.4%) were non-

odontogenic.(figure 3)

DISTRIBUTION OF ODONTOGENIC TUMORS BY HISTOLOGIC TYPE:

The total number of odontogenic tumours was 184. Majority of these were epithelial odontogenic tumours

159 (86.4%) while the least common were mixed odontogenic tumours 12 (6.1%). (Figure 4)

Figure 4: Distribution of odontogenic tumours by histologic types

HISTOLOGIC SUBTYPES OF EPITHELIAL ODONTOGENIC TUMOURS:

Amongst the epithelial odontogenic tumours, ameloblastoma was the most common (72.2%) while the

least common was the squamous odontogenic tumour (0.6%) as shown in table 2.

86.4%

7.1%

6.1%

18

Table 2: Distribution of epithelial odontogenic tumours by histologic subtypes

EPITHELIAL ODONTOGENIC

TUMOURS Frequency Percent

AMELOBLASTOMA 117 72.2

ADENOMATOID ODONTOGENIC

TUMOUR

5 3.1

CALCIFIED EPITHELIAL ODONTOGENIC

TUMOUR

4 2.5

KERATOCYSTIC

ODONTOGENICTUMOUR

35 21.6

SQUAMOUS ODONTOGENIC TUMOUR 1 .6

Total 162 100.0

Figure 5 shows specimen of a large ameloblastoma affecting almost the entire mandible. This may

indicate late reporting by the affected patient.

Figure 5: gross specimen of an ameloblastoma

19

HISTOLOGIC SUBTYPES OF MESENCHYMAL ODONTOGENIC TUMOURS

The most common histologic subtype was the ameloblastic fibroma (40%) and complex odontome (40%).

(Table 3)

Table 3: Distribution of mesenchymal odontogenic tumours by histologic subtype.

Frequency Percent

AMELOBLASTIC FIBROMA 4 40.0

COMPLEX ODONTOME 4 40.0

COMPOUND ODONTOME 2 20.0

Total 10 100.0

HISTOLOGIC SUBTYPES OF MIXED ODONTOGENIC TUMOURS

The most common histologic subtype of mixed odontogenic tumor was the odontogenic myxoma (62.5%)

as shown in table 4

Table 4: Distribution of mixed odontogenic tumours by histologic subtypes

Frequency Percent

ODONTOGENIC FIBROMA 2 25.0

ODONTOGENIC MYXOMA 5 62.5

ODONTOMA 1 12.5

Total 8 100.0

DISTRIBUTION OF NON-ODONTOGENIC TUMORS BY PRIMARY SITE:

The total number of non odontogenic tumours was 141. (table 5)

20

Table 5: Distribution of non-odontogenic tumours by primary site

Frequency Percent

INTRABONY 24 17.0

SOFT TISSUE:EPITHELIAL 62 44.0

SOFT TISSUE:MESENCHYMAL 55 39.0

Total 141 100.0

The most common primary site for non-odontogenic tumours was epithelial soft tissue site. (Table 5)

HISTOLOGIC SUBTYPES OF NON-ODONTOGENIC TUMOURS:

Amongst the non-odontogenic tumours, the pleomorphic salivary gland tumours are the most

common tumours (28.9%) as shown in table 6.

Table 6:Distribution of non-odontogenic tumours by histologic subtypes.

Subtype of non-odontogenic tumours Frequency Percent

PLEOMORPHIC SALIVARY ADENOMA 41 28.9

CEMENTO-OSSIFYING FIBROMA 12 8.5

FIBROLIPOMA 6 4.2

FIBROMA 12 8.5

FIBROUS HISTIOCYTOMA 4 2.8

HEMANGIOMA 3 2.1

LIPOMA 12 8.5

LYMPHANGIOMA 5 3.5

MYXOMA 5 3.5

NEUROFIBROMA 6 4.2

OSTEOMA 3 2.1

SQUAMOUS PAPILOMA 17 12.0

OTHERS 16 11.3

Total 142 100.0

21

SITE DISTRIBUTION OF BENIGN TUMORS: The most common site where the benign tumours occurred was the mandible (44.3%) as shown in table

7.

The least common site was the floor of the mouth (0.9%).

Table 7: Distribution of the benign tumours by site.

Frequency Percent

LIP 13 3.8

TONGUE 22 6.4

GINGIVA/ALVEOLAR 7 2.0

FLOOR OF MOUTH 3 .9

PALATE 36 10.5

BUCCAL MUCOSA 20 5.8

MAJOR SALIVARY

GLANDS

14 4.1

CHEEK 4 1.2

MANDIBLE 152 44.3

MAXILLA 43 12.5

ILLDEFINED ORAL SITES 12 3.5

OTHERS 10 2.9

Total 336 98.0

Incomplete information 7 2.0

Total 343 100.0

Ill defined sites were due to lack of information in the records.

Others include rare sites such as the temporal bone, eye, eye lid, nasal space, peri-auricular and

supraorbital areas.

22

DURATION OF TIME BEFORE PATIENTS SOUGHT TREATMENT:

Figure 6 shows the duration (in months) before patients seek treatment.

44.3% patients sought treatment in less than 2yrs since the symptoms appearance while the rest

(55.7%) sought treatment after 2 yrs.

Figure 6: Duration before patient sought treatment.

For those who sought treatment after 2years, 69% got treatment within 6months, 47% within a

year, 7% within 13-18 months and 21% within 19-24 months (2 years).

Pre-treatment duration

23

CHAPTER 6: DISCUSSION, CONCLUSIONS AND

RECOMMENDATION

6.1: DISCUSSIONS The number of benign tumours to the total number seen between the year 2008-2012 was 325

(43.1%). Benign tumors are most common in the 2nd to the 4th decade of life with a peak in the

3rd

decade at a mean age of 31.99±17.67. These findings are similar to those of a study done by

Dimba et al (2000-2004) on an audit of oral diseases at Nairobi center, which found benign

tumours occurring at a mean age of 29.9-18.27 that peaked in the 3rd

decade (27).

The highest number of patients with benign tumors was seen in the year 2011 as shown in table 1

with a total of 110 (33.8%) cases due to increase number of biopsies brought to the laboratory

though the reason as to why the increased number was not clear.

Amongst the benign tumours the commonest were the odontogenic tumours as shown in figure

2.It contraindicates the results found in Ghana that recorded non-odontogenic to be more

common (29).

Epithelial odontogenic tumours were the most common odontogenic tumors. These included:

ameloblastoma, calcified epithelial odontogenic tumour, squamous odontogenic tumours,

keratocystic odontogenic tumour and adenomatoid odontogenic tumour. Ameloblastoma being

the most common compared to the study done in Libya which reported keratocystic odontogenic

tumour to be the most common (28).

Non–odonotogenic tumors constitute 34% of total benign orofacial tumours of which intrabony

19.6%, fibrous and adipose tissue 53.6% and vascular 26.8% while in Libya they reported 20%

intrabony, 32% fibrous and adipose and 14% vascular (28).

Benign tumours affected the women more than the man as shown in figure 1. This is different to

a study done in Ghana that recorded the benign tumours commonly occur in males (29).

The odontogenic tumours were the most common (56.6%). Amongst the odontogenic the

epithelial tumours were the most common accounting for 86.4%. The most common epithelial

tumour was ameloblastoma (72.2%) and the least was squamous odontogenic tumour

(0.6%).Amongst the mesenchymal odontogenic tumours ameloblastic fibroma(40%) and

complex odontome(40%) were the most common while for the mixed odontogenic tumours

odontogenic myxoma (62.5%) was the most common. Amongst the non-odontogenic the soft

tissue epithelial tumours are the most common (44.0%), of which pleomorphic salivary adenoma

was the most common accounting for 28.9%. However there is scanty information on these.

The most common sites at which benign tumours occur are the jaw bones, mandible and the

maxilla, mandible being 44.3% and maxilla 12.5%.

24

Most patients did not seek treatment at an earlier stage. Most got the treatment after 2years when

the sign and symptoms are severe. The tumour tends to have increased in size and the

management becomes more difficult when the tumour involves vital structures and increased

destruction of bone and normal tissue (3).

6.2: CONCLUSION:

From this study, it can be concluded that there is almost equal prevalence of benign tumours in

the orofacial area as the malignant tumours. The benign tumours affected females more than the

male. Benign tumours are more common in young people from the 2nd

to 4th

decade. The

odontogenic tumours were the most common (56.6%). Amongst the odontogenic, the epithelial

tumours were the most common accounting for 86.4%. The most common epithelial tumour was

ameloblastoma (72.2%). Amongst the non-odontogenic the soft tissue epithelial tumours are the

most common (44.0%), of which pleomorphic salivary adenoma was the most common

accounting for 28.9%. Most patients had the treatment done after 2 years and the most affected

site was the mandible and maxillae.

6.3: LIMITATION

It was difficult to access to clinical files. The study was retrospective and was dependant on

laboratory records.

6.4: RECOMMENDATION

1. Primary health workers should be better trained to diagnose and refer tumours.

2. There should be more pathologists trained in the head and neck area and distributed in

many centers in Kenya for faster results and better prognosis.

3. Communities should be educated on these lesions for them to seek treatment as early as

possible, within 6 months so as to improve the prognosis.

4. More studies to be carried out on larger samples for definitive trend among the tumours

and to develop evidence based strategies for treatment of benign orofacial tumours in

Kenya.

5. Widespread of pathology laboratory with specialized personnel would lead to faster

diagnosis and earlier treatment for better prognosis.

6. An investigation on why an increased number of benign tumours in 2011.

25

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27

APPENDIX 1

WHO CLASSIFICATION OF TUMOURS 2005

These are sub classified into:

1. EPITHELIAL TUMOURS : They composed of odontogenic epithelium but without

odontogenic ectomesenchyme

Ameloblastoma

Squamous odontogenic tumor

Calcifying epithelial odontogenic tumor

Adenomatoid odontogenic tumor

Keratocystic odontogenic tumor

2. MESENCHYMAL TUMOURS: These are composed of odontogenic epithelium with

odontogenic ectomesenchyme with r without hard tissue formation)

ameloblastic fibroma

ameloblastic fibro-odontoma

ameloblastic fibro-dentinoma

odontma, complex and compound

odonoameloblastoma

calcifying cystic odontogenic tumor

dentinogenic ghost cell tumor

3. MIXED TUMOURS

They are composed of odontogenic mesenchyme and/ or ectomesenchyme with or

without epithelium.

Odontogenic fibroma

Odontogenic myxoma and myxofibroma

28

NON-ODONTOGENIC TUMOURS

These are sub classified into:

1. Intra-bony/jaw tumors

2. Soft tissue tumors

INTRA-BONY

osteoma

osteochondroma

cement-ossifying fibroma

central giant cell granuloma

hemangioma

melanotic neuroectodermal tumor

SOFT TISSUE

Soft tissue tumors are further classified into:

I. Epithelial:

Pleomorphic adenoma

Myoepithelioma

Basal cell adenoma

Warthin’s tumor

Oncocytoma

Canalicular adenoma

Sebaceous adenoma

Cystaadenoma

Ductal papillomas

Squamous cell papilloma

II. Mesenchymal :

Myxoma

Fibroma

Angiofibroma

Nodular fasciitis

Fibromatosis

29

APPENDIX 2

Data collection form:

Serial

no:

Patient

file no:

Gender Age Type of

tumor(B=benig

n,

M=malignant)

Type of benign

tumor

Site Duration

before

patient seeks

treatment

30