[Porokeratosis palmaris et plantaris disseminata with squamous cell carcinoma].

A 53-year-old man presented porokeratosis palmaris, plantaris et disseminata with some features (exacerbation of lesions, in the sun light, zosteriform fashion of them on the trunk and extremities) distinctive of other variants of porokeratosis. Lately, four squamous cell carcinomas had arisen on the areas involved by disease. Histologic study of porokeratosis lesions showed epidermal changes typical of the disease ("cornoid lamella"), but also a mild disorder of malpighian stratification. Neoplasms were removed surgically and the patient was given etretinate orally (75 mg/day for a week, 50 mg/day for a month, 25 mg/day for six months, i.e. up to now), which proved to be effective in improving porokeratosis lesions and preventing the occurrence of other squamous cell carcinomas.