[Primary cutaneous CD4+ small- to medium-sized pleomorphic T-cell lymphoma: report of a case with spontaneous resolution].

Primary cutaneous CD4+ smallto medium-sized pleomorphic T-cell lymphoma is included as a provisional entity in the group of primary cutaneous peripheral T-cell lymphomas, both in the latest WHO classification of tumors of hematopoietic and lymphoid tissues and in the WHO-EORTC classification for cutaneous lymphomas. This lymphoma is defined by a predominance of CD4+ smallto mediumsized pleomorphic T cells, with no prior history of macules or plaques that would suggest mycosis fungoides. A 35-year-old man visited our department with an asymptomatic lesion on his left cheek; the lesion had appeared 4 weeks earlier and had grown rapidly. The only relevant information in the patient’s past history was that he had taken allopurinol for 3 months to treat asymptomatic hyperuricemia. He had interrupted this medication 3 days before visiting our department. Physical examination revealed an oval, dome-shaped erythematous tumor measuring 3 x 4 cm on the left cheek. The tumor had well-defined borders and a shiny surface and was indurated on palpation (Fig. 1A). A biopsy of the lesion was taken for histopathology study. The low-magnification view showed that the epidermis was not involved and revealed a dense cellular infiltrate occupying the entire thickness of the dermis and reaching the subcutaneous tissue. The neoplastic infiltrate consisted predominantly of smallto medium-sized lymphocytes with moderate pleomorphism and mild atypia. Numerous histiocytes were also found among the lymphocytes (Fig. 2). Immunohistochemistry showed the cells to be strongly