A malignant eccrine poroma responds to isotretinoin (13-cis-retinoic acid).

In treating a patient with a malignant eccrine poroma, in-vitro studies suggested resistance to dactinomycin and doxorubicin. A trial of weekly 5-fluorouracil produced no response. Likewise, a cycle of cisplatinum and cytarabine was associated with continued progression of the disease. Use of 13-cis retinoic acid induced a partial remission that lasted for 8 weeks with minimal toxicity. The mechanism of action is not known, but local tumor necrosis with sparing of the adjacent normal tissue suggests high specificity.