Linear eccrine poroma.
A 44-year-old woman had multiple papular lesions of 20 years' duration. The lesions were limited to the right lower extremity and were arranged in a linear fashion. They had the histologic appearance of eccrine poroma; however, thin intertwining strands of tumor cells extended down into the dermis in a pattern similar to that of premalignant fibroepithelioma. Also, bud-like proliferations of tumor cells were attached to the epidermis, analogous to those superficial basal cell epithelioma. A dilated cystic duct resembling that found in syringoma was present in the upper part of the dermis. To my knowledge, such a linear distribution of multiple eccrine poromas has not been reported in the dermatologic literature.
D000328:Adult; D005260:Female; D006801:Humans; D013544:Sweat Gland Neoplasms / Q000473:pathology*