Approach to Bone Tumor Diagnosis

7/27/2019 Approach to Bone Tumor Diagnosis

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Diagnostic Approach to Musculoskeletal Tumors

Nur Fatini bt Chok

11 2011 142

Department of Surgry

RSUD Ciawi

JulyAugust 2013

Acknowledgments


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Alhamdulillah, thanks to God because allowed me to submit this manuscript within

the time given. Although there were a lot of things to settle down within this seven weeks, He

had help me to sFpent some time to finish this manuscript.

Second, I would like to thank to my consulant, dr. Dhevariza, the Orthopedist who

sincere and faithfully guide and help me to write this manuscript.

Not forgotten, thank you to my team-mate, who had help me in order to finish up this

manuscript. Thank you for all your ideas and discussion that we had about this topic.

Sincerely, The consulant,

(Nur Fatini Binti Chok) (dr. , Dhevariza, the Orthopedist )

Introduction

Musculoskeletal tumors are a rare and diverse group. Sarcomas of the bone and cartilage

comprise only 0.5% of all malignancies in humans. Their incidence is considerably higher


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in children than adults. The incidence of soft tissue sarcomas is 3 to 4 times higher, and the

majority of these cases are seen after the fifth decade. Benign bone and soft tissue tumors are

100 times more common than malignant tumors, with an overall incidence of300 per

100,000 population. The incidence per year of breast, prostate, and lung cancers in the

United States of America is nearly 180,000 to 200,000 each, reflecting the low incidence of

primary bone and soft tissue tumors. As the survival of patients with carcinomas is gradually

extending, presentation with bone metastases will also rise.

A general orthopedic surgeon or radiologist in the community may encounter only few cases

of bone tumors per year. Patients with an unknown musculoskeletal tumor should be referred

to a specialist center, because the cases are managed in close interaction between the

orthopedic oncologist, radiologist, and the pathologist, and the outcomes are superior.2

This

approach will often eliminate unnecessary diagnostic studies and inappropriate and

inadequate biopsies, which may delay the diagnosis and adversely affect the outcome.

Approach to Bone Tumor Diagnosis

General Considerations:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3036513/#r27185-2http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3036513/#r27185-2http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3036513/#r27185-2http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3036513/#r27185-2


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Bone Tumors can be divided into primary and secondary. Secondary tumors can be further

subdivided into

Metastatic tumors

Tumors resulting from contiguous spread of adjacent soft tissue neoplasms Tumors representing malignant transformation of the pre-existing benign lesions.

Metastatic cancers are the most frequent malignant tumors found in bone. They are by far

more common than primary bone tumors and are characterized by the following:

Predominant occurrence in two age groups: adults over 40 years of age and childrenin the first decade of life.

Multifocality and predilection for the hematopoietic marrow sites in the axial skeleton(vertebrae, pelvis, ribs and cranium) and proximal long bones. Metastases to long

bones distal to the elbows and knees are unusual. Metastases to the small bones of the

hands and feet are even rarer. Occasionally, metastases may appear as solitary lesions

(particularly true for the lung, kidney and thyroid cancer).

Most common malignancies producing skeletal metastases:

Adults More than 75% of skeletal metastases originate

from carcinomas of the prostate, breast, kidney,

and lung. Also common are metastases from

thyroid and colon cancers. And do not forget

melanoma.

Children Neuroblastoma, rhabdomyosarcoma, and

Retinoblastoma

Radiographic appearance of the metastatic tumors can be :

Purely lytic (kidney, lung, colon, and melanoma) Purely blastic (prostate and breast carcinoma) Mixed lytic and blastic (most common appearance)

Primary bone tumors are characterized by the following:

1. Predominant occurrence in the first 3 decades of life, during the ages of the greatestskeletal growth activity. The commonest sites for many primary tumors, both benign and


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malignant, are in the distal femur and proximal tibia, the bones with the highest growth

rate.

2. Relatively specific radiographic presentations. In some cases, the diagnosis can beconfidently made based on the radiographic features alone.

3. Benign tumors are by far more common than malignant ones. Some of them are not trueneoplasms, but rather represent hamartomas (eg., osteochondroma). The most common

benign tumors are osteochondroma, non-ossifying fibroma, and enchondroma.

4. Some primary bone tumors are difficult to classify as benign or malignant. For example,giant cell tumor of bone is very aggressive locally but only rarely metastasizes.

5. Among primary malignant neoplasms, osteosarcoma and multiple myeloma have thehighest incidence, followed by chondrosarcoma and Ewing's sarcoma.

Two important features of bone tumors:

1. The ability of some to dedifferentiate (eg., enchondroma or a low-grade chondrosarcomatransforming into a high-grade sarcoma)

2. Tendency of high-grade sarcomas to arise in damaged bone, at the sites of bone infarcts,radiation osteitis and Paget's disease.

Relevant clinical information

1. Age (probably the most important clinical clue).

Age group Most common benign

Lesions

Most common

malignant tumors

010 simple bone cyst

eosinophilic granuloma

Ewing's sarcoma

leukemic involvement

metastatic

neuroblastoma

1020 non-ossifying fibroma

fibrous dysplasia

simple bone cyst

aneurysmal bone cyst

osteochondroma (exostosis)

osteoid osteoma

osteosarcoma,

Ewing's sarcoma,

Adamantinoma


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osteoblastoma

chondroblastoma

chondromyxoid fibroma

2040 Enchondroma

giant cell tumor

chondrosarcoma

40 and above Osteoma metastatic tumors

myeloma

leukemic involvement

chondrosarcoma

osteosarcoma (Paget's

associated)

MFH

Chordoma

Summary:

Primary osteosarcoma and Ewing's sarcoma are tumors of children and young

adults. Occurrence of chondrosarcomas in children or Ewing's sarcoma in middle-aged

patients is extremely unusual. In individuals older than 40 years, the commonest form of

skeletal malignancy is metastatic cancer. Of the primary bone tumors in this age group,

multiple myeloma and chondrosarcoma are most commonly encountered. Osteosarcomas in

this age group are often secondary malignancies, which develop at the the sites of bone

damage. Giant cell tumor, a locally aggressive lesion, almost exclusively occurs in skeletally

mature patients, 20 to 50 years of age, with closed epiphyses. It is practically never seen in

children or patients older than 60 years.

2. Pain (although a non-specific symptom, it may help in differential diagnosis)Generally, benign non-growing lesions tend to be asymptomatic and represent incidental

findings. Pain may be a symptom of:

Growing lesions. This category includes locally aggressive lesions (eg., aggressiveosteoblastoma and GCT), and malignant tumors

Pathologic fracture complicating either benign or malignant tumor Significant local tissue reaction to the tumor.


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The following clinical symptoms are worth remembering since they may help in the

differential diagnosis:

Osteoid osteoma - small lesion, but highly irritative to adjacent tissues andtypically causes intense night pain relieved by non-steroidal antiinflammatory

drugs. Osteoid osteomas may also occur close to the articular surface of a joint,

causing severe inflammatory synovitis, which often obscures the presence of the

tumor.

Enchondroma vs. chondrosarcoma, grade 1 - histologically, the distinctionbetween a grade 1 chondrosarcoma and an enchondroma is extremely difficult, as

histologic features overlap considerably. The distinction is based on the behavior

of the lesion. One of the clues to clinical behavior is the presence of pain. Low-

grade chondrosarcoma is a growing tumor and, therefore, presents with pain.

Enchondromas tend to be asymptomatic, unless associated with a pathologic

fracture.

3. Multiple lesionsAlthough both benign and malignant tumors may be multifocal, benign lesions tend to

show symmetrical distribution.

Radiological correlation

The following imaging studies are commonly used in evaluation of bone tumors:

1.Plain radiographusually the first imaging technique for a suspected bone lesion since it is inexpensive and

easily obtainable. It is also the best for assessment of general radiological features of the

tumor.

2. Computer tomographyis a method of choice when plain film assessment is difficult owing to the nature of the

lesion (eg., permeative pattern of destruction) or anatomic site (eg., sacrum). In addition,

CT is the best technique in assessment of matrix mineralization, cortical detail, and

detection of the cystic and fatty lesions.

3. MRI( method of choice for local staging. )It is superior to CT in the definition of medullary and extracortical spread and of the

relationship of the tumor to critical neurovascular structures. However, remember that the


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MRI appearances of the majority of bone tumors are totally non-specific. You need to

examine plain films or CT films to define a neoplasm.

4.Bone scintigraphis a highly sensitive but relatively non-specific technique. Its main role is in detection of

suspected metastases in the whole skeleton. It may also be helpful in the detection of

osteoid osteomas ("double density sign" is present in about 50% of cases and is highly

suggestive of this tumor).

Tabel 1 : Morphology of a bone lesion is combined with the age of the patient.

Radiographic examination should answer the following questions:


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What is the precise location of the lesion (type of bone and, if the long bone isaffected, where exactly the lesion is centered - cortex or medulla; epiphysis,

metaphysis or diaphysis)? Some tumors almost exclusively occur at specific sites;

many oth ers favor certain locations.

Is there any evidence of underlying bone abnormality (eg., bone infarct, Paget'sdisease)? High-grade sarcomas tend to arise in damaged bone.

Is the lesion multifocal? Does the tumor have a well-defined margin? Is there a rim of sclerotic bone? The

presence of a well-defined margin and a sclerotic rim strongly suggests a benign non-

growing lesion.

Is there evidence of significant cortical expansion or destruction? These findings areseen with locally aggressive or malignant tumors.

Is there an associated periosteal reaction and, if so, of what type? Does the lesion produce mineralized matrix (osteoid or cartilage)? Is there a soft tissue mass?

In many cases, the radiographic appearance of the lesion provides clues to its clinical

behavior. It allows estimation of tumor growth rate and discloses expansive or infiltrative

growth patterns characteristic of locally aggressive and malignant tumors.

Skeletal location


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While many lesions favor certain bones, some tumors almost exclusively occur at specific

sites :

Lesions Most common skeletal sites

Ewing's sarcoma

Multiple myeloma

Leukemia/lymphomaMetastatic cancers

Hematopoietic marrow sites in

the axial skeleton (vertebrae,

ribs, sternum, pelvis, cranium)and proximal long bones

(femur, humerus)

Non-ossifying fibroma Metadiaphyseal regions of the

tibia and distal femur (80%)

Does not occur in the flat bones, craniofacial

bones, the spine, or the small bones of the

hands/feet.


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Simple bone cyst The vast majority of SBCs is

found in the proximal humerus

(55%) and proximal femur (20%).

Chordoma Base of the skull or sacrum(90%)

Adamantioma Mid-shaft of tibia (90%), jaw bones

Chondroblastoma Long bones (knee area,

proximal humerus)-70%

Giant cell tumor Knee area, distal radius (65%)

Enchondroma Small bones of the hands and

feet (60%). This is in fact the

commonest tumor at these sites.

Chondrosarcoma (primary, and to

the less extent secondary)

Tends to develop in the axial

skeleton with 25% to 30%

occurring in the pelvic bones

Fibrous dysplasia Femur, tibia, skull and ribs

Ostochondroma Knee area, proximal humerus,

Pelvis

Osteoblastoma Spine (30%), mandible, long bones

Aneurysmal bone cyst Any bone; common in the

Spine

Chondromyxoid fibroma Knee area (30%), pelvis, small

bones of the feet

Hemangioma Spine, craniofacial bones

Site of Long Bone Involvement

(most primary bone tumors have favored sites within long bones; this may provide a clue to

diagnosis).


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Epiphyseal lesions:

1. Chondroblastoma (Ch) and Giant Cell Tumor (GCT) arealmost invariably centered in the epiphysis.

2. Chondroblastoma is a rare tumor seen in children andadolescents with open growth plates. GCT is the most

common tumor of epiphyses in skeletally mature

individuals with closed growth plates. GCT often shows

metaphyseal extension.

Metaphyseal intramedullary lesions:

1. Osteosarcoma is usually centered in the metaphysis.2. Chondrosarcoma and fibrosarcoma often present as

metaphyseal lesions. Osteoblastoma, enchondroma,

fibrous dysplasia, simple bone cyst, and aneurysmal bone

cyst are common in this location.

Metaphyseal lesions centered in the cortex:

Classic location for a non-ossifying fibroma (NOF).

Also, a common site for osteoid osteoma.

Metaphyseal exostosis:

Osteochondroma

Diaphyseal intramedullary lesions:

Favored location for Ewing's sarcoma, lymphoma,

myeloma. Common for fibrous dysplasia and

enchondroma.

Diaphyseal lesions centered in the cortex:

Adamantinoma, osteoid osteoma

Pattern of Growth and Bone Destruction


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Benign and non-growing (or extremely

slowly growing) lesions are well

circumscribed and show geographic pattern

of bone destruction with a sclerotic rim.

1. Geographic pattern refers to awelldefined area of lysis.

2. The sclerotic rim is more commonlyseen in the weight-bearing bones and

represents bone reaction to the lesion.

Its presence means that the bone has

been given sufficient time to react.

Some authors say that the sclerotic rim

signifies benignancy to about 95%.

If the lesion is growing more rapidly,it may

still show a well-demarcated zone of bone

destruction (geographic pattern), but it will

lack a sclerotic rim. With continued growth,

such lesions may show cortical expansion.

Expansile growth pattern is defined as visible

widening of the affected portion of bone. In

many cases, an interrupted periosteal rim will

surround the expanded portion of bone. This

pattern may be seen in locally aggressive

tumors and in lowgrade malignancies.


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Rapidly growing lesions are poorly defined

and may show aggressive, infiltrative

patterns of bone destruction (permeative or

"motheaten").

"Moth-eaten" pattern is defined as an ill-

defined zone of multiple small radiolucencies

that may coalesce.

Permeative pattern is characterized by

numerous tiny radiolucencies in between the

residual bone trabeculae. Due to the minute

size of radiolucencies the lesion may be

difficult to see and to delineate on the plain

film. Generally, the more rapidly growing a

lesion, the more difficult it is to see on plain

film. "Moth-eaten" and permeative patterns

are indicative of destruction involving both

medullary and

cortical bone. They are seen in highgrade

malignant neoplasms and in

osteomyelitis.

Types of Periosteal Reaction

The periosteum responds to traumatic stimuli or pressure from an underlying growing tumor

by depositing new bone. The radiographic appearances of this response reflect the degree of

aggressiveness of the tumor.


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Slow-growing tumors provoke focal cortical

thickening (solid periosteal

reaction, or "buttress")

Rapidly growing lesions penetrate

through the cortex causing separation

of the periosteum and formation of

lamellated new bone. If the

periosteum elevates to a significant

degree, it can break forming an acute

angle (Codman's triangle). This is

seen in malignant bone tumors and in

some other rapidly growing lesions

such as aneurysmal bone cyst, or in

reactive processes (osteomyelitis,

and subperiosteal hematoma).

Codman's triangle is usually free of

tumor unless infiltrated through its

open end or by transcortical growth.

Other types of periosteal reaction in

response to a rapidly growing lesioninclude "onion-skinning" and

spiculated "hair-on-end" types.

Note that bone metastases usually do not provoke a periosteal reaction.


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Pattern of matrix Mineralization

Mineralization patterns (calcification or ossification) are helpful in identification of bone

producing and cartilage producing tumors.

Osteoid. Malignant osteoid can be recognized

radiologically as cloudlike or ill-defined

amorphous densities with haphazard

mineralization. This pattern is seen in

osteosarcoma. Mature osteoid, or organized

bone, shows more orderly, trabecular pattern

of ossification.

This is characteristic of the benign bone-

forming lesions such as osteoblastoma.

Chondroid. Radiologically, it is usually

easier to recognize cartilage as opposed to

osteoid by the presence of focal stippled or

flocculent densities, or in lobulated areas as

rings or arcs of calcifications. They are best

demonstrated by CT. Whatever the pattern, it

only suggests the histologic nature of the

tissue (cartilage) but does not reliably

differentiate between benign and malignant

processes.

General Histologic Assessment of the Lesion

The following are the most important histologic features to consider:

Pattern of growth (eg., sheets of cells vs. lobular architecture) Cytologic characteristics of the cells Presence of necrosis and/or hemorrhage and/or cystic change Matrix production Relationship between the lesional tissue and the surrounding bone (eg., sharp border

vs. infiltrative growth)


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You should never try to make a diagnosis of bone tumor without integrating clinical,

radiological, and histologic appearances. Biologically different types of tumors may have

overlapping histologic features. Always obtain a list of differential diagnoses from a

radiologist, make a habit of reviewing the films, and develop a good working relationship

with an orthopedic surgeon. You are a part of a team.


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Soft Tissue Mass

Introduction

A soft tissue mass is one of the most common manifestations of a musculoskeletal tumor.

Proper diagnosis and treatment are essential to avoid the potential for loss of limb function

and to maximize the opportunity to cure a soft tissue sarcoma. The large majority of soft

tissue tumours are benign, with a very high cure rate after surgical excision. Malignant

mesenchymal neoplasms amount to less than 1% of the overall human burden of malignant

tumours but they are lifethreatening and may pose a significant diagnostic and therapeutic

challenge since there are more than 50 histological subtypes of STS, which are often

associated with unique clinical, prognostic andtherapeutic features. Over the past decade, our

understanding of these neoplasms has increased significantly, both from a histopathological

and genetic point of view. Careful physical examination and radiographic evaluation to

evaluate the size, depth and location of the mass, along with signs of neurovascular

involvement are essential for designing the best therapeutic approach.

History

When obtaining the patient history, consider:

1. The patient's age.Infants and children may present with benign lesions that can demonstrate local growth,

disfigurement, overgrowth of the extremity or loss of function (lipomas, hemangiomas,

lymphangiomas, neurofibromas, hamartomas, congenital or infantile fibromatosis). Soft

tissue sarcoma is extremely rare in children, but when it occurs, it is most likely to be

rhabdomyosarcoma. In adults, rhabdomyosarcoma is rare in the extremities.

2.The length of time that the lesion has been present.The patient may have had a benign soft tissue lesion for several years that has not grown

during that time. He or she may finally decide to "get this bump looked at," or may be

encouraged to consult a physician by a spouse or a friend. The pattern of growth is

important: A mass that has been present for years and that begins to grow may be

transforming from a benign to a malignant lesions, or it may simply be growth of a

benign soft tissue tumor. Rapid growth may also indicate that the mass may be malignant.

Growth of a soft tissue tumor, therefore, warrants further evaluation.


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3. The presence of pain.Although often tender to direct pressure, a soft tissue tumor itself rarely causes the patient

pain. The exceptions are peripheral nerve sheath tumors and rapidly growing soft tissue

sarcomas, which may cause pressure on surrounding structures and intra-compartmental

compression. If the patient is experiencing pain, also consider other diagnoses, such as

infection.

4. A history of trauma.Chronic repetitive trauma to the soft tissues may cause reactive fibrosis; a more acute,

severe injury may suggest myositis ossificans. It is not unusual for a patient to discover a

soft tissue mass after a major or minor trauma to the anatomical area -- or to mistakenly

believe that the injury caused the lesion. If the mass persists following trauma, a complete

workup is needed to establish whether it is related to the trauma (such as a persistent

hematoma) or is, in fact, a soft tissue tumor. Ask about a past history of penetrating

trauma or infection -- an old soft tissue infection or foreign body reaction may lead to the

late presentation of a calcified soft tissue mass.

5. Possible generalized conditions.Neurofibromatosis is the best example of a generalized disease that may be associated

with one or more soft tissue masses. A patient with this disease may present with benign

growth of a plexiform neurofibroma, or alternatively, a benign nerve sheath tumor may

transform into a neurofibrosarcoma. Multiple soft tissue benign myxomas may develop in

a patient with extensive fibrous dysplasia of the bones and cafe au lait spots (possibly

associated with premature onset of menses in the McCune-Albright syndrome). A patients

with Maffucci's syndrome (multiple bone enchondromas associated with soft tissue

hemangiomas) may present with transformation of a hemangioma to angiosarcoma.

6. Family history of soft tissue masses.This is particularly pertinent to the diagnosis of neurofibromatosis. In some cases of

familial cancer syndromes (Li-Fraumeni syndrome related to the inheritance of a mutant

p53 allele, for example), family members may have a high risk of developing soft tissue

sarcoma as well as other forms of cancer.


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Physical Examination

The physical examination of a patient with a possible soft tissue tumor includes the

following:

1. Depth.One of the most critical aspects of the physical examination is determining whether a

lesion arising deep to dermis is superficial or deep to fascia; most lesions developing

superficial to fascia are benign. In making this determination, attempt to move the lesion

over the fascia, both before and after the patient tenses the underlying muscle. If the

lesion moves with the muscle, it is likely deep to fascia. In some instances, it may be

impossible to tell if the lesion is deep or superficial; the lesion may even arise from the

fascia. As discussed below, the investigation and management of soft tissue lesions

depends on the depth of the mass. Those arising deep to fascia have the greatest risk of

malignancy. If the physical examination indicates that the lesion arises in fascia, deep to

fascia, or is uncertain, obtain imaging of the mass.

2. Size.After determining the depth, document the clinical size of the lesion in three dimensions.

Evaluate the condition of the overlying tissues, determining whether there is evidence of

inflammation that suggests either soft tissue infection or a rapidly growing tumor.

Tenderness could also indicate a rapidly growing tumor, a peripheral nerve sheath tumor,

or infection. Observe the surrounding skin for evidence of vascular changes that may

suggest multiple vascular malformations. Particularly in children, document evidence of

extremity overgrowth, including measurement of the extremity length and diameter.

3. Distal neurovascular status.Test for a nerve deficit or evidence of venous or arterial obstruction by evaluating distal

neurovascular status. Soft tissue tumors rarely cause a neurological deficit. Instead, nerve

deficit usually indicates that the tumor is arising in the peripheral nerve or is invading the

nerve. Examine the skin should for evidence of cafe au lait spots, dermatofibromas, or

axillary freckling, which may suggest neurofibromatosis or, in the case of cafe au lait

spots, fibrous dysplasia.

4. Regional nodes.Palpate the regional nodes, although soft tissue sarcomas rarely metastasize by

lymphangitic spread. Rhabdomyosarcoma and synovial sarcoma are the most likely

diagnoses if nodal metastases are found. Examine the other extremities and trunk for soft


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tissue masses; lipomas -- and less commonly liposarcoma -- may present in multiple sites.

Advanced metastatic carcinoma or lymphoma may spread to the non-nodal soft tissues;

therefore, evidence of a primary cancer elsewhere must be evaluated on both history and

physical examination.

5. Dermatological lesions.The only dermatological lesion related to musculoskeletal tumors is dermatofibrosarcoma

protuberans. This lesion is elevated above the dermis, purplish in color, and

characteristically develops satellite nodules as it grows. It behaves like a low-grade soft

tissue sarcoma and is generally managed in a similar manner. Subcutaneous malignant

fibrous histiocytomas may also result in invasion of the dermis, but generally malignant

mesenchymal lesions do not develop primarily in the skin.

Investigations

Results of the history and physical examination will guide the next steps:

1. Lesion Less than 5 cm in Diameter Observation is appropriate for this size lesion if it is also soft in consistency,

superficial to fascia, not enlarging, and not cosmetically or functionally troubling.

Measure and record the size of the lesion annually for 2 or 3 years.

If a lesion this size bothers the patient or is firm, painful, or enlarging, it cangenerally be removed by excisional biopsy, taking care to avoid violating the

underlying fascia. Send the specimen for appropriate pathological analysis, and if the

pathologist determines it to be a soft tissue sarcoma, locally curative management

can then be achieved by re-excising the surgical scar and incorporating the fascia as a

deep margin. Avoid excisional biopsy and obtain imaging and a needle or incisional

biopsy prior to excision if the lesion is located in an anatomical region that would

preclude later re-excision (for example, if a small lesion is located directly over the

bone in the subcutaneous tissues overlying the ulna or tibia).

2. Superficial Lesion Larger than 5 cm in Diameter Before attempting excision, evaluate a lesion this size by magnetic resonance

imaging (MRI). MRI is more appropriate for evaluating soft tissue tumors than

computerized tomography (CT) scan because the enhanced soft tissue contrast of

MRI allows for optimal demarcation of the lesion from surrounding normal soft


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tissues and for assessment of possible neurovascular involvement. It is likely that a

superficial lesion greater than 5 cm is lipoma. If this is confirmed by MRI, the

lesion may be observed or treated by excisional biopsy, depending on growth

characteristics and patient preference.

3. Needle or incisiona l, ra ther than ex ci sion al , biopsy should be undertaken if thelesion does not demonstrate a lipoma's typical well-demarcated, homogeneous pattern of

fat on MRI, or if there are any regions of high (bright) T2-weighted signal within the fat

of the tumor. Critically evaluate whether there is any evidence of edema surrounding the

superficial tumor. If the margin with normal surrounding subcutaneous fat is not sharp

and discrete on MRI, a biopsy should be done prior to excision.

4. Lesion Attached to Fascia, Deep to Fascia, or Depth UnknownMRIshould be undertaken to diagnose the lesion. The potential diagnoses for deep

lesions include benign conditions (intramuscular lipoma, hemangioma, myxoma, benign

peripheral nerve sheath tumor), benign aggressive tumors likely to recur locally after

simple excision (fibromatosis, hemangiopericytoma), and soft tissue sarcoma. Effective

treatment of many of these lesions will include wide surgical excision, and the likelihood

of achieving adequate surgical removal with minimal functional deficit is enhanced if the

patient is initially evaluated with MRI and carefully planned biopsy. Conversely, it may

be very difficult to perform adequate surgical excision with conservation of function if

the initial treating physician performed an excisional biopsy of a subfascial sarcoma,

which would cancer cells throughout the extremity. If the depth of the lesion is not

apparent on physical examination, the clinician should err on the side of ordering imaging

before attempting a biopsy.

Suspected or Confirmed Diagnosis of Soft Tissue Sarcoma

In these cases, metastatic staging with chest CTis necessary. Lymphatic spread to nodal

groups may be assessed clinically and, if suspected, assessed by CT scan.

If there is a history of trauma in a patient with a soft tissue mass, plain radiographs may

demonstrate the typical peripheral ossification pattern seen in myositis ossificans. In most

cases of soft tissue masses however, plain radiographs are of little value, although they may

demonstrate increased soft tissue lucency caused by a large fatty lesion or the calcification

occasionally observed in lipomas, liposarcomas, or synovial sarcomas. Bone scans are not

useful in most cases either, since soft tissue tumors rarely invade the bone cortex. If the bone

cortex is invaded, a CT scan may be more useful than either a bone scan or an MRI because a


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CT scan usually gives the best anatomical definition of the extent of bony destruction. In

general, though, MRI is the most effective imaging modality for soft tissue masses.

Blood work is not usually helpful in the diagnosis of soft tissue masses, although a complete

blood count, ESR and C-reactive protein may be helpful if infection is suspected. Patients

with myositis ossificans or soft tissue osteosarcoma may have an elevated serum alkaline

phosphatase.

Conclusion

In summarizing the investigation of patients with soft tissue masses, the following guidelines

are suggested:

If the lesion originates in or deep to fascia, or if the depth is uncertain, cross-sectionalimaging should be ordered.

1. If the lesion is superficial to fascia and larger than 5 cm, imaging should be undertaken. Inour experience, MRI is preferred to CT. However, if MRI is not available, CT is often

sufficient for initial investigation.

After localizing the lesion anatomically, it is necessary to obtain a biopsy of most deeplesions. An initial biopsy for superficial lesions that are greater than 5 cm is also suggested.

Deep soft tissue lesions should never be treated with an excisional biopsy. Doing so makes

definitive management much more difficult and therefore should be avoided.


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WHO classification of soft tissue tumours


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Reference:

1. Onder Ofluoglu, Stefano Boriani, Rakesh Donthineni ( 2010 ). Diagnosis and Planning inthe Management of Musculoskeletal Tumors: Surgical Perspective. Retrieved from

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3036513/

2. Violetta Barbashina, Joseph Benevenia, Meera Hameed ( 2004 ). Bone Tumors Tutorialfor Residents. Retrieved from http://www.umdnj.edu/tutorweb/

3. Woulde HJ, Robih Smithuis ( 2010 ). Bone Tumors Systemic Approach andDifferential Diagnosis. Retrieved from http://www.radiologyassistant.nl/ en/

p494e15cbf0d8d

4. Soft tissue mass. Retrieved from http://www.orthopaedicsone.com /display/ Main/Soft+tissue+mass
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3036513/http://www.umdnj.edu/tutorweb/http://www.radiologyassistant.nl/en/p494e15cbf0d8dhttp://www.radiologyassistant.nl/en/p494e15cbf0d8dhttp://www.radiologyassistant.nl/en/p494e15cbf0d8dhttp://www.radiologyassistant.nl/en/p494e15cbf0d8dhttp://www.umdnj.edu/tutorweb/http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3036513/

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