High endothelial venules in extranodal lymphomas with emphasis on their prognostic significance.

In the present study, the frequency of occurrence of high endothelial venules (HEVs) in extranodal lymphomas at various sites was examined, and its prognostic implication subsequently estimated. The presence of HEVs was tested for by an immunohistochemical method using the monoclonal antibody, HECA-452, known to be specific for HEVs. The number of cases at each extranodal site were 13 in the thyroid, three in the salivary gland, 15 in the gastrointestinal(GI) tract, 20 in the brain, six in the lung, 12 in the pleura, nine in the testis, 10 in the bone, 19 in the skin and seven in the breast. Histologically, 26 of the 114 cases (23%) were of high grade malignancy according to the Working Formulation. Immunohistochemistry revealed 89 cases (78%) to be of B-cell type, eight (7%) T-cell type and 17 (15%) others. HEVs were observed frequently among the cases of lymphoma of the salivary gland (100%), thyroid (77%), GI tract (53%), lung (50%) and breast (43%). Evident were a preponderance of female patients (P less than 0.02) and those with histologically favorable lymphoma types (P less than 0.001), and a more favorable prognosis (P less than 0.001) for cases with HEVs over those without. There were no significant differences in age and immunologic type distributions between cases with and without HEVs. The findings suggest that the presence of HEVs could be used as an indicator for a favorable prognosis in cases of extranodal lymphoma.