Mycosis fungoides with mucinosis follicularis in childhood.
Mycosis fungoides is a cutaneous T-cell lymphoma (CTCL) usually observed in mid to late adulthood. It occurs only rarely during childhood. Follicular mucinosis is a chronic dermatosis involving the sebaceous glands and outer root sheaths. It is normally differentiated into a juvenile benign form and an adult form possibly associated with mycosis fungoides. We report a 12-year-old boy who presented with an 8-month history of erythematous mucinous plaques on the scalp. Three months later, he developed erythematous patches and plaques on his whole body, accompanied by cervical lymphadenopathy. A biopsy showed follicular mucinosis and epidermotropism of the lymphocytic infiltrate. Immunophenotyping and a PCR clonality test were consistent with CTCL. The patient received PUVA treatment and local steroids, resulting in partial remission. Mycosis fungoides should be considered in the differential diagnosis of chronic, scaling dermatoses in childhood. Moreover, follicular mucinosis in childhood can be associated with mycosis fungoides.