Primary Cutaneous Follicle Center Lymphoma in An HTLV-1 Carrier.

Human T-lymphotropic virus type 1 (HTLV-1) is an oncogenic retrovirus associated with adult T-cell leukemia/lymphoma (ATLL), an aggressive neoplasm of mature CD4+ T-lymphocytes which always shows monoclonal integration of HTLV-1 provirus DNA. HTLV is not associated with B-cell non-Hodgkin's lymphoma (B-NHL); however rare cases of B-NHL have been reported in HTLV-1 carriers, leading some to hypothesize a role for HTLV-1 in B-cell lymphogenesis. We report a case of a Jamaican male HTLV-1 carrier with primary cutaneous follicle center lymphoma of B-cell origin and explore the link between HTLV-1 and B-NHL.

A 55 year old Jamaican male was seen in our hematology clinic for evaluation of multiple scalp masses progressive over six months. The lesions were painful, pruritic, but not associated with other constitutional symptoms. He had been in good health prior to the onset of these symptoms, and denied toxic habits or exposures. Physical examination revealed multiple firm, non-tender scalp masses, the largest measuring 3.0 × 2.0 cm; the overlying skin was nodular and erythematous but without breakdown or discharge. His complete blood count, basic metabolic profile, hepatic function and lactate dehydrogenase were all within normal limits. On excisional biopsy, the dermis showed a dense lymphoid infiltrate of medium to large sized cells, with a nodular and trabecular pattern of growth from the superficial dermis to the aponeurosis. Numerous large centroblast-like cells were present. Immunohistochemical stains demonstrated the following phenotype: CD45+, CD20+, CD79a+, BCL2+/-, BCL6+/-, CD10+, and MUM-/+. A stain for CD21 highlighted compact and fused/contiguous follicular dendritic cell meshworks in association with the neoplastic B-cell infiltrate. Staining with Ki-67 highlighted a variable but high proliferation rate (80%). A moderate infiltrate of small-sized T-cells (CD3+, CD5+) was also present. These features were diagnostic of a primary cutaneous follicle center lymphoma. Evaluation with the MYC breakapart probe showed no evidence of rearrangement; RT in-situ PCR for HTLV-1 showed a signal in many of the infiltrating T-cells. He was seropositive for positive HTLV-1 and negative for HIV and EBV infection. Bone marrow biopsy and aspiration and additional staging CTs were unremarkable. The patient received 4 cycles of R-CHOP chemotherapy and has been in a complete remission for 2 years.

We report a case of a Jamaican male HTLV-1 carrier with cutaneous lymphoma of B-cell origin with detection of HTLV-1 proviral DNA in the neoplastic cells by RT in-situ PCR. Our findings lead us to speculate that HTLV-1 infected T-cells and/or an immunodeficient state in certain HTLV-1 carriers might allow for the development of B-cell lymphoma. Further research on the pathogenesis of HTLV-1 in B cell lymphomagenesis needs to be explored.

No relevant conflicts of interest to declare.