Differential survival of systemic B-cell lymphomas initially diagnosed in the skin: a population-based study of 883 patients.

Although the majority of lymphomas are diagnosed in lymph nodes, bone marrow, or other viscera, initial diagnosis of systemic lymphomas in the skin is a rare but important occurrence in dermatology. This study seeks to quantify the incidence of initial skin presentation in patients with systemic B-cell lymphomas (BCL) via examination of data in the Surveillance, Epidemiology, and End Results (SEER)-18 database; cases of primary cutaneous B-cell lymphoma were excluded. We found that an initial diagnosis of lymphoma in the skin is a very rare occurrence for systemic B-cell lymphomas, comprising < 0.3% of cases overall. Follicular lymphoma was the most likely to be diagnosed in the skin (1.47%), followed by marginal zone lymphoma (MZL, 0.5%), mantle cell lymphoma (0.4%), diffuse large B-cell lymphoma (DLBCL, 0.23%), Burkitt lymphoma (0.23%), Hodgkin lymphoma (0.04%), and chronic lymphocytic leukemia (0.006%). While indolent systemic lymphomas (MZL and FL) presenting initially in the skin have a better prognosis than those presenting at other sites, the more aggressive systemic DLBCL presenting in the skin does not demonstrate improved prognosis.