Cutaneous pheomorphic T cell lymphoma. Immunologic, virologic, and T-cell receptor gene rearrangement studies in one European case with initial pseudolymphoma presentation.

An unusual case of cutaneous nodular T cell lymphoma evolving for 4 years with massive eosinophilia and greatly increased IgE levels is discussed. Repeated histologic and immunohistologic examinations could not ascertain malignancy because tumors were composed of a granuloma-like, highly polymorphic cellular infiltrate with mature immunotype and no significant nuclear abnormalities nor epidermotropism. T cell lymphoma was evidenced by the T cell receptor beta-chain gene study, which showed a clonal rearrangement. Final histologic classification was "pleomorphic T cell lymphoma" because further biopsy samples displayed numerous lymphoid cells with pleomorphic convoluted nuclei. The T-cell receptor gene probe is a major tool for the early diagnosis of some T cell lymphomas. The case we report shares many features with the smoldering type of human T cell lymphotropic virus type I-associated Japanese endemic pleomorphic T cell lymphoma. Our virologic study confirms that in nonendemic Western countries, pleomorphic T cell lymphomas do not show evidence of a retrovirus association.