[Flutamide-induced late cutaneous pseudoporphyria]

Pseudoporphyria is a condition characterized by clinical and histological changes resembling porphyria cutanea tarda, in the absence of any demonstrable abnormality in porphyrin metabolism. Etiologies of pseudoporphyria are hemodialysis for chronic renal failure, chronic UV irradiation, and several drugs, particularly naproxen. We report a case of flutamide induced pseudoporphyria.

A 75-year-old man had prostatic carcinoma and was treated with flutamide for 1-1/2 years. He presented with a several months history of blisters on the back of the hands and fingers, occurring after sun exposures. The bullae were associated with skin fragility and atrophic scarring. Histopathological examination and direct immunofluorescence showed ultrastructural features close to those described in porphyria cutanea tarda. Quantitative analysis of porphyrins in urine and laboratory blood tests were normal. Flutamide was stopped, leading to healing of the lesions, with no relapse after 11 months.

Flutamide is an antiandrogen used for the treatment of prostatic carcinoma. Its principal side-effect is represented by liver toxicity. Cutaneous side-effects of flutamide are uncommon; three cases of photo-allergic dermatitis have been described, and we report with our observation, the third case of cutaneous pseudoporphyria induced by flutamide.