Lichenoid Granulomatous Mycosis Fungoides.

The presence of a granulomatous reaction in cutaneous lymphomas has been described in the past, especially in mycosis fungoides (MF), where a "granulomatous" variant of the disease is well known. We describe a patient with granulomatous MF (GMF) who has been followed for 13 years presenting with erythematosquamous plaques on his fingers and toes, ankles, heels, and abdomen, which on microscopic examination showed a lichenoid granulomatous reaction admixed with a neoplastic proliferation of small-sized, atypical CD4 lymphocytes. GMF is characterized by a granulomatous reaction intermingled with the dermal infiltrate of MF which may even reach the subcutaneous tissue. Only 7 cases of GMF in which the granulomas were located within the papillary or superficial dermis have been described to date. We report for the first time a unique case of lichenoid GMF where the granulomatous reaction obscures the interface between the epidermis and dermis. Sequential biopsies and complete phenotypic studies were necessary to get an accurate diagnosis.