T-cell receptor gene rearrangement in regressing atypical histiocytosis

A case of regressing atypical histiocytosis having characteristic clinical and light microscopic findings was studied immunologically for immunoglobulin and T-cell receptor gene rearrangement and for DNA ploidy analysis. Immunologic phenotyping and rearrangement of T-cell receptor Beta- and gamma-chain genes indicated that this primary cutaneous neoplasm, previously considered "histiocytic" in origin, is most probably of T-cell lineage.