Smoldering HTLV-1-induced T-cell lymphoma localized within the skin; a radiation-resistant tumor

Human T-cell lymphotrophic virus type 1 (HTLV-1)-induced lymphoproliferative disease occurs in approximately 3-5% of people in endemic areas who have been HTLV-1 positive for decades. Lymphoproliferative disease may present as four subtypes, including an acute adult T-cell leukemia/lymphoma (ATLL), an aggressive HTLV-1 lymphoma, chronic ATLL, and smoldering ATLL.

A 72-year-old HTLV-1+ Haitian woman presented with a 2-year history of a cutaneous eruption localized to the right arm. The eruption had evolved into multinodular lesions over the past 6-7 months. Peripheral blood and cutaneous biopsy specimens were evaluated. Immunohistochemical studies for lymphoid markers were performed on the cutaneous biopsy material, and polymerase chain reaction (PCR) and Southern blot assay were evaluated for the presence and integration of HTLV-1 within the genome.

The biopsy specimen showed a pleomorphic T-cell infiltrate with epidermotrophism, and an immunohistochemical phenotype showing CD3+, CD4+, CD8-, CD25, CD30-, HLDA-DR+ cells. PCR and Southern blot assay evaluation showed a single clonal integration of HTLV-1 provirus within a monoclonal tumor cell population. The patient had no abnormal lymphoid forms on peripheral smear at presentation, and no evidence of other organ involvement.

Smoldering HTLV-1-induced lymphoma is uncommon even in endemic areas. In previously reported cases, the smoldering variant was accompanied by abnormal forms in the peripheral blood and/or by other signs of systemic disease. This case illustrates that smoldering disease may be localized to the skin with no detected morphologic abnormalities on peripheral smear.