Mycosis fungoides mimicking perioral dermatitis.

A 71-year-old woman under PUVA-treatment for mycosis fungoides developed erythematous patches around the nasolabial folds and papules on the chin with clinical features of perioral dermatitis. Histology showed a specific infiltrate of mycosis fungoides with predominance of medium to large-sized pleomorphic lymphocytes and immunoblasts. Immunohistochemical analysis revealed the T-phenotype of the neoplastic cells. Small clusters of B-lymphocytes could also be observed within the infiltrate. Perioral dermatitis-like lesions can be added to the spectrum of rare and unusual clinical manifestations of mycosis fungoides.