Bone marrow precursor of extranodal T-cell lymphoma

The development of extranodal lymphomas is thought to be initiated by the transformation event in peripheral organs. Lymphomatold papulosis (LyP) is a low-grade cutaneous lymphoma and may progress into the cutaneous anaplastic lymphoma. We identified 2 patients who 3 and 4 years before the development of LyP were treated for an unrelated malignancy (Burkitt lymphoma and small-cell B-cell lymphoma). We analyzed the T-cell receptor (TCR) gene rearrangement pattern in their skin, blood, and bone marrow, including the archival bone marrow sampled years before the development of clinically evident LyR In all samples we detected the unique monoclonal TCR rearrangements. This observation suggests that the initial malignant transformation in LyP occurred in bone marrow and not, as could be supposed, in the skin. (C) 2003 by The American Society of Hematology.