Gynecomastia in type-1 neurofibromatosis with features of pseudoangiomatous stromal hyperplasia with giant cells. Report of two cases.

We describe the histological finding in two cases of gynecomastia in patients with von Recklinghausen's disease. The histological and immunohistochemical features of the two cases were reviewed and compared with those of five cases of gynecomastia in men without clinical evidence of neurofibromatosis. In both patients bearing von Recklinghausen's disease, the breast stroma showed features consistent with pseudoangiomatous stromal hyperplasia (PASH). It was characterised by anastomosing empty spaces lined by spindle and multinucleated giant cells which were positive with CD34 and anti-vimentin antisera and negative with anti-FVIII and CD31 antisera. In two of five of the control cases without neurofibromatosis, the mammary stroma showed focal areas with features of PASH, but no multinucleated giant cells were present in any case. PASH with giant cells should be recognised as a feature of gynecomastia in von Recklinghausen's disease. The presence of multinucleated giant cells is very unusual and, although more cases have to be studied, these cells seem to be a feature of PASH occurring in patients with von Recklinghausen's disease.