Primary hepatosplenic CD5-positive diffuse large B-cell lymphoma: a case report with literature review.

De novo CD5-positive diffuse large B-cell lymphoma (CD5(+) DLBCL) accounts for approximately 10% of DLBCL, and is usually associated with aggressive clinical course. We report a case of CD5(+) DLBCL with primary involvement of the spleen and liver, and no distinct mass lesions or lymphadenopathy. The patient had stage IV disease with bone marrow involvement by lymphoma. The lymphoma cells showed characteristic portal and intrasinusoidal pattern of infiltrate in the liver. The literature was reviewed and the clinicopathologic features of 7 similar reported cases were summarized. All cases share the common features of hepatosplenomegaly without mass lesions, exclusive red pulp infiltrate with a diffuse and cordal pattern in the spleen, portal and intrasinusoidal pattern of infiltrate in the liver, and stage IV disease with poor response to conventional chemotherapy. This may represent a distinct subgroup of CD5(+) DLBCL and the diagnosis is important for prompt clinical treatment.