Acanthosis nigricans-like hyperpigmentation secondary to triazinate therapy.

Cutaneous hyperpigmentation resembling acanthosis nigricans developed in two patients with malignant brain tumors following chemotherapy with triazinate (Baker's Antifol), a folic acid antagonist. In both cases, the eruption resolved after the cessation of drug administration and reappeared after the reinstitution of triazinate therapy. A skin biopsy specimen from one patient showed microscopic changes consistent with those found in acanthosis nigricans. The other patient had a decreased serum folate level that returned to normal as the hyperpigmentation resolved. Folate may have a role in triazinate-induced acanthosislike hyperpigmentation.