Epidermotropic presentation by splenic B-cell lymphoma: The importance of clinical-pathologic correlation.

There are exceedingly rare reports of patients with epidermotropic B-cell lymphomas. A subset presented with intermittent, variably pruritic papular eruptions and involvement of their spleens, peripheral blood and bone marrow at the time of diagnosis. Furthermore, some experienced an indolent course despite dissemination of their lymphomas. We report a 66-year-old woman with a 12-year history of intermittent eruptions of non-pruritic, salmon-colored papules on her torso and proximal extremities that occurred in winter and resolved with outdoor activity in spring. Skin biopsy revealed an epidermotropic B-cell lymphoma with a non-specific B-cell phenotype and heavy chain class switching with IgG expression. On workup, our patient exhibited mild splenomegaly and low-level involvement of her peripheral blood and bone marrow by a kappa-restricted B-cell population. A splenic B-cell lymphoma was diagnosed. Considering her longstanding history and absences of cytopenias, our patient has been followed without splenectomy or systemic therapy. Furthermore, the papules have responded dramatically to narrowband UVB. Our case and a review of similar rare reports aim to raise awareness among dermatopathologists and dermatologists of a clinically distinct and indolent subset of epidermotropic splenic lymphomas with characteristic clinical and histologic findings.