Adult T-cell leukemia/lymphoma (ATL) is is a rare and aggressive T-cell lymphoma that is linked to infection by the human T-cell lymphotropic virus 1 (HTLV-1). The exact mechanism by which HTLV-I infection causes the ATL is unknown. The clinical features of ATL include generalized swelling of the lymph nodes (lymphadenopathy), increased liver and spleen size (hepatosplenomegaly), immunosuppression, high levels of calcium in the blood, lytic bone lesions (spots that appear as “holes” on a standard bone x-ray), and skin lesions.  There are four basic clinical variants of ATL: acute (60% of cases), lymphomatous (20 % of cases), chronic (10% of cases) and smoldering (10% of cases). The best treatment for these patients is unclear and patients should be enrolled in clinical trials whenever possible. Medication may include CHOP chemotherapy (cyclophosphamide, doxorubicin, vincristine and prednisone) or EPOCH (etoposide, vincristine, doxorubicin, cyclophosphamide and prednisone). In some patients, a bone marrow transplant may be recommended.