Membranous basal cell adenoma of the salivary gland: a clinicopathologic study of 12 cases.

Twelve cases with membranous basal cell adenoma of the salivary gland were analysed clinicopathologically. Its histology was characterized by palisading of peripheral cells and an excessive hyaline basal membrane. The differential diagnosis involved the solid variant of basal cell adenoma, basal cell adenocarcinoma, solid subtype of adenoid cystic carcinoma and basaloid squamous cell carcinoma. Four cases had coexisting dermal cylindromas of the scalp. Screening for skin lesions of the scalp or other locations is suggested. In 8 cases, the tumors demonstrated multifocal origin. Total parotidectomy rather than superficial parotidectomy is suggested to avoid the recurrence of the tumor. One case showed malignant transformation and cervical lymph node metastases. A close follow-up after treatment is necessary.