Childhood T-cell malignancy resembling adult T-cell leukemia/lymphoma.

We describe two childhood cases of a T-cell malignancy indistinguishable from nonendemic, idiopathic adult T-cell leukemia/lymphoma. The cases illustrate the heterogeneity of nonendemic, idiopathic ATLL, including the presence of mediastinal masses and more heterogeneous immunologic markers than endemic cases, and represent the two youngest cases of ATLL yet described. The differential diagnosis of nonendemic, idiopathic ATLL is discussed.