Syringoacanthoma: an acrosyringeal tumour.

Syringoacanthoma is a rare benign appendage tumour derived from the intraepidermal portion of the acrosyringium. We report its occurrence in 3 women. In each case the tumour clinically most resembled a seborrhoeic keratosis. Its importance histopathologically lies in the need to differentiate it from conditions such as malignant melanoma, squamous cell carcinoma, intraepidermal carcinoma, Paget's disease and metastasis, which may all show intraepidermal spread.