Primary cutaneous marginal zone B-cell lymphoma: clinical and histological aspects.

According to the WHO-EORTC classification of cutaneous lymphomas, primary cutaneous marginal zone B-cell lymphoma are now well characterized. We report here a case of primary cutaneous marginal zone B-cell lymphoma in a 51 year-old man in which the diagnosis was made using both histology and immunopathology. The patient had no remarkable medical history, no history of either acute inflammation or insect bite, and presented with a 5 cm solitary asymptomatic erythematous firm, multinodular and infiltrated plaque on the back for 12 months. Histological examination and immunohistochemical study of a cutaneous biopsy provided a differential diagnosis between B cell lymphoma and lymphocytoma cutis. Full body work up revealed no signs of extracutaneous dissemination. The patient underwent surgical excision of the nodule. Histological examination showed a histological and immunophenotyping profile typical of primary cutaneous marginal zone B-cell lymphoma. The lesion was completely excised with clear margins and no recurrence occurred after a 12 month-follow-up period. Primary cutaneous marginal zone B-cell lymphoma are low-grade lymphomas that have an indolent course and a high tendency to recur. They should be differentiated from lymphocytoma cutis and from the other types of cutaneous B cell lymphomas that have a different course and prognosis.