SYNOPSIS OF THYROID PATHOLOGY
BABATUNDE A. OLATIDOYE, M.D.
The thyroid gland is a unique organ located in the anterior portion of the neck. It has three lobes and weighs 15 to 20gm. The function of the thyroid gland is essential for growth, development and normal metabolism. Malfunction of the thyroid gland can be attributed to one of the following; (I) imbalance of certain thyroid hormones, (II) inflammation of the thyroid gland and (III) development of a benign or malignant tumor.
An imbalance in certain thyroid hormones can lead to hypothyroidism and manifests as myxedema (dry firm waxy swelling of skin and subcutaneous tissue). Severe hypothyroidism shows some of the following clinical manifestations; brittle and dry hair, lethargy, memory impairment, slow cerebration, edema of face and eyelids, slow speech, deep coarse voice, sensation of coldness, diminished perspiration, enlarged heart, hypertension, coarse and dry scaling skin, slow pulse, menorrhagia or amenorrhea late in disease and muscle weakness. Hyperthyroidism (diffuse) known as Graves’ disease shows clinical manifestations including exophthalamus (protruding eyes), goiter, increased perspiration, tachycardia, muscle wasting, shortness of breath, breast enlargement (gynecomastia in male), increased appetite, weight loss, diarrhea, tremor, rapid pulse, warm and moist palms, oligomenorrhea or amenorrhea, relative lymphocytosis and monocytosis.
Another malady of the thyroid gland is caused by inflammation (thyroiditis). The most common type of thyroiditis is chronic lymphocytic thyroiditis (Hashimoto’s thyroiditis). This is an autoimmune disorder that occurs more frequently in female at any age and causes hypothyroidism. Another thyroiditis that is not as common as Hashimoto’s is granulomatous thyroiditis (deQuervain’s thyroiditis). This is a self-limiting disease with an acute onset resulting in painful thyroid gland, fever, chills and symptoms of hyperthyroidism.
Tumors of the thyroid gland can be classified as either benign or malignant. The most common benign tumor is called adenoma and occur more frequently in women. It is usually well demarcated, encapsulated and can reach great size. Malignant tumors of the thyroid gland includes (I) Papillary carcinoma, (II) Follicular carcinoma, (III) Hurthle cell carcinoma, (IV) Medullary carcinoma, (V) Insular carcinoma, (VI) Anaplastic carcinoma, (VII) Metastatic carcinoma and (VIII) Malignant lymphoma. Papillary carcinoma is the most common malignant neoplasm representing over 60% of all thyroid malignant neoplasms with female to male ratio of (8:1). The most aggressive of the thyroid cancer is anaplastic carcinoma. Papillary carcinoma is the least aggressive of the thyroid cancers, however, it frequently metsstases to cervical lymph node and follows an indolent course with favorable prognosis. The most aggressive of the thyroid cancer is anaplastic carcinoma and constitutes less than 3% of thyroid malignancies. The aggressiveness of the other thyroid cancers falls between papillary carcinoma and anaplastic carcinoma. Medullary carcinoma comprises approximately 3%. They are characterized by high serum level of calcitonin. Metastatic malignancies to the thyroid gland occurs rarely. The common sites of primary tumor metastasizing to the thyroid gland include breast, lung, kidney, and gastrointestinal tract. Primary malignant lymphomas of the thyroid constitutes about 6 to 7% of all thyroid malignancies with a female to male ratio of (4:1) and presents in the background of chronic lymphocytic thyroiditis.
Most of this thyroid pathology is amenable to fine needle
aspiration. Among Wilmington Pathology Associates’ six
pathologists, are two board-certified cytopathologists, Babatunde
A. Olatidoye, MD and Debra B. Novotny, MD, who review and
diagnose the most difficult FNA biopsy cases.