PSEUDOANGIOMATOUS HYPERPLASIA OF MAMMARY STROMA ASSOCIATED WITH GYNECOMASTIA

Aims-To evaluate the prevalence of pseudoangiomatous hyperplasia of ma mmary stroma in gynaecomastia and its immunohistochemical profile in t his setting. Methods-Eighty eight cases of gynaecomastia recovered fro m the files of the department of pathology, Botucatu School of Medicin e from 1976 to 1996 were studied. In the cases associated with pseudoa ngiomatous hyperplasia of mammary stroma, immunoreactivity for cytoker atins (CAM 5.2), vimentin, CD34, factor VIII related antigen, and the oestrogen and progesterone receptors were studied. Results-Pseudoangio matous hyperplasia of mammary stroma was found in 21 of 88 cases of gy naecomastia (23.8%). In all cases, the cells lining the spaces were po sitive for vimentin, whereas CAM 5.2 and factor VIII related antigen w ere consistently negative. Nineteen of the 21 cases showed immunoreact ivity for CD34. Ductal epithelial cells were positive for both the oes trogen receptor and the progesterone receptor, whereas stromal cells w ere negative. Conclusions-Pseudoangiomatous hyperplasia of mammary str oma was present in approximately one quarter of the cases of gynaecoma stia. This immunohistochemical study confirms the mesenchymal origin o f the stromal cells that line the pseudovascular spaces, as has been f ound in female cases of pseudoangiomatous hyperplasia of mammary strom a.