CD5 positive follicular lymphoma: prognostic significance of this aberrant marker?

Abstract

Follicular lymphoma is a heterogeneous entity that includes tumours derived from germinal centre B cells, and is the most common of the clinically indolent non-Hodgkin lymphomas. The immunophenotypic pattern of follicular lymphoma classically demonstrates the B-cell markers CD19, CD20, CD22, surface immunoglobulin and CD10. The tumour cells are usually negative for CD5. Two cases of CD5 positive follicular lymphoma have been diagnosed in the last 6 months at Wol-longong Hospital, which was demonstrated on immunopheno-typing of involved bone marrow. This has not previously been described. <h3>Aim</h3> To discuss the two cases of CD5 positive follicular lymphoma. <h3>Methods</h3> Case histories, laboratory results and personal correspondence were used to summarise each case. Review of bone marrow biopsies showing involvement with follicular lymphoma was performed spanning the last 24 months at Wollongong Hospital. The flow cytometry results of each was studied for the presence of CD5 positivity, and compared to the result of CD5 positive im-munohistochemistry on the trephine. <h3>Results</h3> Two cases of 8 (25%) of follicular lymphomas with marrow involvement were found to be CD5 positive. <h3>Discussion</h3> CD5 positive follicular lymphoma has not previously been described. The clinical and therapeutic significance of this remains uncertain, and more research into such cases would be helpful to establish whether the presence of this aberrant marker bears any prognostic significance for the patient.