A case series of adult T-cell leukemia-lymphoma, associated with human T-cell leukemia virus type-1, at a single center in a non-viral-endemic metropolitan area

We examined 13 patients with adult T-cell leukemia-lymphoma (ATL) diagnosed between 2007 and 2018 at a single center in a metropolitan area non-endemic for human T-cell leukemia virus type I (HTLV-1). The median age of the patients (eight male, five female) was 65 years (range, 48-83). The time from onset of symptoms to referral to our center was relatively short (median, 2 months; range, 1-9 months). Upon referral, all patients were suspected to have lymphoma, five were examined for soluble IL-2 receptor and two were examined for anti-HTLV-1 antibody. In ten of the 13 (77%), the patient themselves or their relatives were born in Kyushu. The birth places of the remaining three patients were unknown. Three patients (23%) had family histories of lymphoma. They all exhibited aggressive ATL (five acute, eight lymphoma type); however, the disease status was generally stable, with relatively stable performance status and low scores for prognostic indices. After combination chemotherapy, eight (62%) achieved remission. However, long-term remission was achieved in only one patient with localized lymphoma-type ATL and one young patient after allogeneic hematopoietic stem cell transplantation. In conclusion, at a center in a metropolitan and HTLV-1 non-endemic area in Japan, patients with ATL were relatively young and mainly presented with aggressive subtypes. At initial referral to our center, all 13 patients were suspected of having lymphoma but only two of having ATL. For centers in similar areas of Japan, prompt diagnosis and appropriate treatment of ATL patients will become increasingly necessary following the recent migration of HTLV-1 carriers to non-endemic areas.