Basaloid and lobulated: Sebaceous adenoma.

Abstract

Sebaceous adenoma is a benign epithelial neoplasm with hyperplasia of sebaceous lobules associated with expansive aggregates of basaloid germinative cells. Sebaceous adenomas usually demonstrate solitary or multiple lesions, particularly in the head and neck. Sebaceous adenomas can be associated with Muir-Torre syndrome which is a familial disorder with concomitant emergence of sebaceous neoplasm and a visceral malignancy or a concurrence of multiple keratoacanthomas and a visceral malignancy. Few to hundreds of gradually evolving, painless, yellow coloured papules or nodules with or without ulceration of the superficial epithelium are seen. Sebaceous adenomas commonly display distinct zones of clustered sebaceous lobules which are comprised of equivalent quantities of differentiated sebaceous cells and undifferentiated basaloid cells, accumulated within the papillary dermis. Mature sebaceous cells are immune reactive for Epithelial membrane antigen (EMA) and non-reactive for Carcino-embryonic antigen (CEA). Basaloid cells of sebaceous neoplasm are immune reactive for cytokeratin 7. Sebaceous adenoma requires distinction from sebaceous hyperplasia, sebaceous carcinoma, disorders with sebaceous differentiation, clear cell variations of eccrine, melanocytic, keratinocytic and xanthomatous conditions. Sebaceous adenoma is adequately managed by a comprehensive surgical excision with consequent minimal tumour reoccurrence.