Primary cutaneous B cell lymphoma

Cutaneous lymphomas, arising from T or B lymphocytes, constitute an uncommon but nevertheless important entity, with the so-called Skin Associated Lymphoid Tissue (SALT) being either the origin (primary) or the target (secondary) in the neoplastic process.[1] The primary cutaneous lymphomas, by definition, present clinically on the skin with no extracutaneous disease at the time of diagnosis or for 6 months thereafter.[2] Of these, primary cutaneous lymphomas of B cell origin are less common, their incidence being one-third that of their T cell counterpart.[3] Although several classifications like Kiel, Lukes and Collins, Rappaport and Revised European and American Lymphoma (REAL)[4] classification have been used, the one proposed by the European Organisation for Research and Treatment of Cancer (EORTC)[3] is the latest one and is being followed widely. The follicular centre cell type described in the EORTC classification is the commonest type of primary cutaneous B cell lymphoma and shows a characteristic histopathology[5] and expression of cell surface markers like CD 19, CD 20, CD 79a.[1],[6] One such case is described below.

A 54-year-old male, who had been a road layer for 30 years, presented with a one-year history of progressively enlarging swellings over the face, chest and forearm. The lesions were mildly photosensitive.

On examination, multiple tumor masses of firm consistency were found infiltrating the forehead and malar areas to produce a ′leonine′ appearance [Figure - 1]. The overlying skin was hyperpigmented and with a ′peau d′orange′ appearance. Similar lesions were present on the neck, upper back and dorsal aspect of forearms. No significant lymphadenopathy was detected clinically.

Histopathology of the involved skin showed a normal epidermis with absence of epidermotropism. A clear subepidermal cell free Grenz zone was seen in the papillary dermis. The mid and lower dermis were densely infiltrated by small, round lymphocytes in a ′bottom heavy′ pattern [Figure - 2]. Radiological and bone marrow aspiration studies revealed no extracutaneous pathology.

Immunohistochemistry for cell markers was done. A final diagnosis of primary cutaneous B cell lymphoma or follicular centre cell type was made based on immunohistochemistry with Bcl-2 antibodies.

Chemotherapy with cyclophosphamide, adriamycin, vincristine and prednisolone was started. An excellent response with near total resolution of lesions was seen [Figure - 3]. The patient is being followed up at regular intervals.

The follicular centre cell type of primary cutaneous B cell lymphoma with its classical histopathology[5] and cell markers, as seen in this case, has a favorable prognosis with good therapeutic response, a fact well documented.[2],[7] Interestingly, with the patient′s history of lifelong exposure to coal tar and sunlight, and with the lesions being limited to the exposed areas of the body, the possibility of these environmental factors playing a carcinogenic role in primary cutaneous B cell lymphoma, although hitherto unreported, needs to be further explored.