Nonendemic adult T-cell leukemia/lymphoma in the United States: report of two cases and review of the literature.

Adult T-cell leukemia/lymphoma (ATLL) is a recently described distinct clinicopathologic entity characterized by a leukemic or lymphomatous proliferation of hyperlobulated peripheral T-cells, which is usually widespread at presentation and is associated with infection by a type C retrovirus. ATLL rarely is described outside of endemic regions, which include southwestern Japan, the Caribbean region, and the southeastern United States. The authors report the clinical, pathologic, and immunologic features of two cases of nonendemic ATLL that occurred in patients from the midwest United States. One patient was a 16-year-old white girl from rural Iowa, and the other was a 46-year-old white man from rural Minnesota. The features of 13 other probable nonendemic ATLL cases from the United States were compiled and reviewed. In the United States, nonendemic ATLL occurred in widespread geographic locations, affected mostly white people, and was characterized by an aggressive course with generalized adenopathy, blood and bone marrow involvement, and hepatosplenomegaly at presentation. Skin involvement was present in one-fourth of the patients. Hypercalcemia was rare. Although antibodies to type C retrovirus were detected in three of the five patients tested, the available data is not sufficient to establish a conclusive association between nonendemic ATLL and type C retrovirus infection.