■ Parathyroid Carcinoma Parathyroid carcinoma is a malignant neoplasm arising from the parathyroid parenchymal cells, comprising approximately 1% of all primary hyperparathyroidism (HPT) cases (no malignant adipose tumors are recognized in the parathyroid). Secondary parathyroid hyperplasia and neck irradiation are…
■ Parathyroid Adenoma A parathyroid gland adenoma is an encapsulated benign neoplasm of the parathyroid parenchymal cells (either chief or oncocytic cells). Parathyroid disease is separated into primary, secondary, or tertiary, based on whether the parathyroid gland is primarily the…
■ General Considerations There are a variable number of glands (2 to 10), but usually four are present, symmetrically arranged within the upper and lower poles of the bilateral thyroid gland. Approximately 5% of people have more than four glands.…
Thyroid gland malignancies account for about 3% of all cancers (13.5/100,000 population), while representing the most common malignancy of the endocrine system. In general, thyroid cancer afflicts young to middle-aged adults with environmental, genetic, and hormonal factors often playing an…
▪ Follicular Adenoma Follicular adenoma (FA) is a benign encapsulated neoplasm of follicular epithelial origin and is the most common neoplasm of the thyroid gland. Autopsy studies show that 3% to 5% of adult thyroid glands harbor an FA. A…
■ Thyroglossal Duct Cyst The thyroglossal duct represents the tract in the midline neck through which the thyroid anlage descends during embryonic development. It begins at the foramen cecum at the base of the tongue, continues around the hyoid bone,…
■ Squamous Cell Carcinoma (External Auditory Canal and Middle Ear) Squamous cell carcinoma (SCC) is a malignant tumor of squamous keratinocytes. Ultraviolet (UV) radiation is considered etiologic for external ear lesions, whereas chronic inflammation (otitis media) may be associated with…
▪ Ceruminous Adenoma Ceruminous adenoma is a benign glandular neoplasm of ceruminous glands (modified apocrine sweat glands) that arises solely from the external auditory canal (EAC). Clinical Features Ceruminous Adenoma—Disease Fact Sheet Definition ▪ Benign ceruminous gland neoplasm Incidence and…
▪ First Branchial Cleft Anomalies First branchial cleft anomalies include a spectrum of benign congenital fistulas, sinuses, and cysts and result from incomplete fusion of the first and second branchial arches, with persistence of the ventral component of the first…
■ Osteomyelitis Osteomyelitis (osteitis) is an inflammatory or infectious process in the marrow cavities of the bone. It may be either acute or chronic. There are many classification schemes, including composition of the infiltrate (acute, subacute, chronic, granulomatous), infectious agent…