Thyroid tumors Dr. Gehan Mohamed
Jan 03, 2016
Thyroid tumors
Dr. Gehan Mohamed
Classification of thyroid tumors
• A- benign tumors: more common than malignant thyroid neoplasm.
e.g follicular thyroid adenoma
B- Malignant thyroid tumors.
Criteria for diagnosis of follicular adenoma
• 1- solitary nodule
• 2- encapsulated
• 3- presence of compressed thyroid tissue outside capsule of thyroid adenoma.
Classification of Malignant Thyroid Neoplasms
• Papillary carcinoma• Follicular variant• Tall cell• Diffuse sclerosing• Encapsulated
• Follicular carcinoma• Overtly invasive• Minimally invasive
• Hurthle cell carcinoma• Anaplastic carcinoma
• Giant cell• Small cell
• Medullary Carcinoma• Miscellaneous
• Sarcoma• Lymphoma• Squamous cell carcinoma• Mucoepidermoid
carcinoma• Clear cell tumors• Plasma cell tumors• Metastatic
– Direct extention
– Kidney
– Colon
– Melanoma
Normal Thyroid
colloid
Thyroid epithelial cells
T4 90%
T3 10%
TSH
Types of Thyroid Cancer
• Papillary (80%-85%): develops from thyroid follicle cells in 1 or both lobes; grows slowly but can spread
• Follicular (5%-10%): common in countries with insufficient iodine consumption; lymph node metastases are uncommon
• Medullary: develops from C-cells, can spread quickly; sporadic .
• Anaplastic: develops from existing papillary or follicular cancers; aggressive, usually fatal
• Lymphoma: develops from lymphocytes; uncommon
Risk Factors for development of thyroid carcinoma
• Radiation• High dose x-rays of the neck or face during
infancy or teenage years is a risk factor specially for papillary carcinoma
• Family History• Goiters and prolonged TSH stimulation is a risk for
follicular carcinoma.• Mutated RET oncogene
• Gender• males
When suspect malignancy in thyroid mass
• 1-Male sex
• 2- Solitary thyroid nodules in patients >60 or <30 years of age
• 3-Large Nodules (>3 or 4 cm) with rapid Growth
• 4-Symptoms especially a change in voice,Pain,dysphagia,Stridor,hemoptysis
Molecular Level
• Medullary Carcinoma• Mutation in RET gene
• Papillary Carcinoma• Mutated RET, RAS, or BRAF gene
Typical Presentation of Thyroid Cancer
• Painless lump• Normal thyroid function tests• Found on routine examination or by the patient
Papillary Carcinoma
•Most common type
•Females outnumber males 3:1– Highest incidence in women in midlife.
•Lymph node involvement is common Major route of metastasis is lymphatic
Papillary Thyroid CancerCharacteristics
• Unencapsulated tumor nodule with ill-defined margins
• Tumor typically firm and solid
• First presentation of the patient may be lymph node
enlargment.
• Commonly metastasizes to neck and mediastinal lymph
nodes
– 40% to 60% in adults and 90% in children
• <5% of patients have distant metastases at time of
diagnosis
– Lung is most common site
Thyroid carcinoma
Micropapillary thyroid carcinomas
Definition - papillary carcinoma smaller
than 1.0 cm
Most are found incidentally at autopsy
Usually clinically silent
Papillary Carcinoma(continued…)
• Pathology Gross - vary considerably in size
- often multi-focal
- unencapsulated but often have a pseudocapsule which is
normal thyroid tissue compressed by the tumor mass.
Histopathology - closely packed papillae which have
fibrovascular core.
- psammoma bodies which is a laminated calcification
- nuclei are oval or elongated, pale staining
with ground glass appearance .
Papillary carcinoma of thyroid
Papillary Thyroid Cancer: nuclei are oval or elongated, pale staining with ground glass
appearance
Follicular variant of papillary carcinoma
2- Follicular Thyroid Carcinoma
• Second most common type of thyroid cancer
• Solid invasive tumors, usually solitary and
encapsulated
• Usually stays in the thyroid gland, but can spread to
the bones, lungs, and central nervous system.
• Usually does not spread to the lymph nodes
Follicular Carcinoma
• Pathology Gross - encapsulated, solitary
Histology - very well-differentiated.
(distinction between follicular adenoma and
follicular carcinoma is so difficult so we
depend on presence of vascular and
capsular invasion to diagnose follicular
carcinoma.
Invasive follicular carcinoma:malignant follicles invade pink fibrous capsule
Follicular thyroid carcinoma
Hürthle Cell Carcinoma
• A variant of follicular cancer that
tends to be aggressive
• Microscope : there are Large,
polygonal, eosinophilic thyroid
follicular cells with abundant
granular cytoplasm and
numerous mitochondria High power magnification
Hürthle Cell Tumor
Hürthle Cell tumor
• May be benign or malignant, based on
demonstration of vascular or capsular
invasion
• Malignancies tend to have a worse
prognosis than other follicular tumors
• Tend to be locally invasive
3- Anaplastic Thyroid Cancer
• Often occurs in the elderly population (mean
age: 65 years)
• Three fold greater risk in iodine-deficient
areas
• Tumor is typically hard, poorly circumscribed,
and fixed to surrounding structures.
• Extremely aggressive and exceptionally
virulent
Anaplastic Carcinoma of the Thyroid
• Pathology Classified as
Composed wholly or in part of undifferentiated cells
which may be large cell or small cell
Large cell is more common and has a worse prognosis
Histology - sheets of very poorly differentiated cells
little cytoplasm
numerous mitoses
necrosis
extrathyroidal invasion
Medullary Thyroid Carcinoma
Tumor arising from the calcitonin-secreting C-cells of
the thyroid gland.
• Developes in 3 clinical settings: Sporadic MTC (SMTC)
Familial MTC (FMTC)
Multiple endocrine neoplasia.
Medullary Thyroid Carcinoma characterized by presence of pink amyloid in between malignant cells.
Medullary Thyroid CancerMetastases
• Cervical lymph node metastases occur early
• Tumors >1.5 cm are likely to metastasize,
often to bone, lungs, liver, and the central
nervous system
• Metastases usually contain calcitonin and
stain for amyloid
Evaluation of any thyroid Nodule(Physical Exam)
• Examination of the thyroid nodule:
consistency - hard vs. soft
size – more than 4.0 cm
Multinodular vs. solitary nodule– multi nodular : 3% chance of malignancy
– solitary nodule : 5%-12% chance of malignancy
Physical Exam (continued…)
• Examine for ectopic thyroid tissue
• Indirect or fiberoptic laryngoscopy
vocal cord mobility
evaluate airway
Evaluation of the Thyroid Nodule
Advantages of Ultrasonography•Noninvasive and inexpensive
•Most sensitive procedure or identifying lesions in the
thyroid (can detect smaller lesions even 2-3mm size)
•90% accuracy in categorizing nodules as solid, cystic, or
mixed
•Best method of determining the volume of a nodule
•Can detect the presence of lymph node enlargement and
calcifications
Ultrasonography (Continued…)
• Disadvantages Cannot accurately distinguish benign
from malignant nodules