Primary diffuse large B-cell lymphoma of the skin.

B-cell lymphomas of the skin represent a wide spectrum of disorders. We present the microscopic and immunohistochemical features of a primary cutaneous B-cell lymphoma and classify it either as a diffuse large B-cell lymphoma or an indolent follicle-center-cell lymphoma according to the updated REAL/WHO system and the EORTC classification respectively. The former system is widely recommended; nevertheless, the EORTC system is also worth considering when planning management, because most data on long-term outcomes are based on it and it is considered to offer remarkable prognostic information.