[Midline peripheral T-cell lymphoma--an immunohistochemical and electron microscopy study].

Twenty-six cases of nasal/nasopharyngeal midline peripheral T-cell lymphomas were studied clinically and pathologically with immunohistochemical markers and electronmicroscopy. A clearer understanding of the nature of midline malignant reticulosis has obtained. Immunohistochemical markers confirmed that except 5 small specimens which failed to show the monoclonal growth, 18 cases had peripheral T-cell lymphomas, 15 had TH, 3 Ts and 2 B-Cell lambda light chain and 1 HC. Morphological observations showed that 24 cases out of 26 exhibited middle and small polymorphic T-cells. This tumor had distinctive clinical features and was characterized by midfacial progressive necrosis, slow growth, local invasion and rarely metastasis, often with prominent granulomatous and vascular proliferation. Therefore, a discrimination of this disease from midline malignant reticulosis and midfacial destructive lesions is absolutely necessary.