Ceruminous adenoma

A ceruminous adenoma (also known as adenoma of the ceruminous gland and ceruminoma) is a benign glandular neoplasm which arises from the ceruminous glands located within the external auditory canal. These glands are found within the outer one third to one half of the external auditory canal, more common along the posterior surface; therefore, the tumor develops within a very specific location.

Ceruminous adenoma are rare tumors, accounting for less than 1% of all external ear tumors. The patients will present with a mass, perhaps associated pain, and may have changes in hearing (usually a sensorineural or a conductive hearing loss). Some patients have tinnitus. Nerve paralysis is very uncommon.

The tumors are usually small, with a mean size of about 1.2 cm. The tumors are separated into three histologic types based on the dominant findings:

All of the tumors are unencapsulated, but are usually well defined or circumscribed. The overlying surface epithelium is not involved. The tumor shows a dual or biphasic appearance, with glandular or cystic spaces showing inner luminal secretory cells with abundant granular, eosinophilic cytoplasm subtended by basal, myoepithelial cells at the periphery, adjacent to the basement membrane. The luminal cells will often have decapitation (apocrine) secretions and will also have yellow-brown, ceroid, lipofuscin-like (cerumen) pigment granules. There is no pleomorphic, limited mitoses, and no necrosis.

can be performed to confirm the biphasic nature of the tumor. All cells are positive with pancytokeratin and epithelial membrane antigen; only the luminal cells are positive with CK7; only the basal cells are positive with CK5/6, p63, S100 protein. CD117 can be positive in either population. The cells are negative with chromogranin, synaptophysin and CK20.

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