Histiocytic cytophagic panniculitis: molecular evidence for a clonal T-cell disorder.

Histiocytic cytophagic panniculitis is a systemic disease of unknown etiopathogenesis that invariably involves the subcutaneous fat and is histologically characterized by phagocytosis of blood elements by histiocytes that appear to be benign. Immunophenotypic and genotypic studies of biopsy specimens of the lesions of a 58-year-old woman showed that the lymphocytic infiltrates accompanying the histiocytes in the subcutis were composed of clonal T-cells with rearrangement of the surface receptor gene. Our findings suggest that the primary abnormality in histiocytic cytophagic panniculitis may be a clonal T-cell proliferation.