An Aggressive Course of Transformed Splenic Diffuse Red Pulp Small B-Cell Lymphoma With Novel Somatic Loss-of-Function Mutation in .

Splenic diffuse red pulp small B-cell lymphoma (SDRPL) is an extremely rare B-cell lymphoma. The disease is typically indolent and treatment with splenectomy usually results in durable remissions. Here, we present a case of an extremely aggressive course of SDRPL with transformation to diffuse large B-cell lymphoma and multiple relapses immediately following cessation of immunochemotherapy.