HTLV-I-associated leukemia/lymphoma in south Florida.
 We report here 10 cases of adult T-cell leukemia/lymphoma (ATL) seen in South Florida between February 1988 and July 1989.
 All were seropositive for human T-lymphotropic virus type I (HTLV-I) and seronegative for human immunodeficiency virus type 1 (HIV-1).
 DNA extracted from tumor biopsies/peripheral blood lymphocytes of nine patients was shown by the polymerase chain reaction (PCR) to contain HTLV-I proviral DNA.
 Blot hybridization of DNA extracted from seven patients with an HTLV-I cDNA probe revealed a monoclonal pattern of proviral integration consistent with a diagnosis of ATL.
 Eight of the 10 patients were women.
 Six patients were from Haiti, three from Jamaica, and one from the Bahamas.
 All patients had very aggressive non-Hodgkin's lymphoma.
 Two patients presented with sinus and retro-orbital involvement; another had gastric lymphoma that perforated.
 Nine patients developed hypercalcemia.
 Eight patients died within 1 year of diagnosis.
 Two were lost to follow-up.
 During the course of this study, 66 new cases of non-Hodgkin's lymphoma were diagnosed at this hospital.
 Ten of these cases were ATL.
 The prevalence of HTLV-I-related lymphoma in this sample was 15%.
 Since tissue from all patients was not available for HTLV-I screening, however, it is possible that other cases of ATL went undetected.
 We conclude from this initial survey that a retroviral etiology should be considered in patients from populations known to be at risk for HTLV-I infection who present with non-Hodgkin's lymphoma.
