Cutaneous-type adult T-cell leukemia/lymphoma. A unique clinical feature with monoclonal T-cell proliferation detected by Southern blot analysis.

A 60-year-old woman suffered from multiple subcutaneous nodules with a self-limited clinical course. High titer of the antibody against the adult T-cell leukemia/lymphoma (ATL)-associated cell antigen was detected and atypical lymphocytes were present in less than 1% of the peripheral leukocytes. Tumor cells were identified by the molecular biology technique Southern blot analysis, which showed monoclonal cell expansion of the helper/inducer T cells integrated with human T-cell lymphotropic virus type I/adult T-cell leukemia virus. This patient was diagnosed as having the cutaneous type of smoldering ATL in a very early stage. In this case, only gene analysis of the skin lesion could facilitate making an early differential diagnosis of ATL from other lymphoproliferative diseases, including nonviral cutaneous T-cell lymphoma and benign lymphoid hyperplasia.