Aggressive squamous cell carcinoma arising in familial acne conglobata.

Familial acne conglobata is more widespread and severe than "ordinary" acne conglobata and involves unusual areas such as the antecubital fossae and ankles. Of six members in one family with familial acne conglobata, two developed large and aggressive, well-differentiated squamous cell carcinomas within their disease. One had destruction of a large part of the right cranial vault; the other had most of his second cervical vertebra destroyed by metastatic squamous cell carcinoma. Isotretinoin controlled the granulomatous acneiform lesions but had no effect on the cancers.