Cytological diagnosis of Paget's disease of the nipple by scrape smears: a report of five cases.

Five cases of mammary Paget's disease were diagnosed by nipple scrape cytology. The neoplastic material obtained was abundant in two cases, moderate in one, but in two, only a few cell aggregates feature in three cases and this, together with dense tumour cell cytoplasm and the background of keratinous debris, may impart a squamous-like appearance; however, three-dimensional cell aggregates, papillary-like groups, acinar-like collections, and some cells with vacuolated cytoplasm and eccentric nuclei allowed glandular differentiation to be inferred in three cases. In four cases a combination of clinical evaluation, and cytological findings of malignant cells compatible with Paget's disease was used so that mastectomy could proceed, and in one case there was frozen section confirmation of an underlying invasive carcinoma. In the single case in which it was performed, there was positive immunoperoxidase staining for c-erb B2 oncoprotein. Demonstration of this protein, CEA, or mucin, helps distinguish Paget's disease from melanoma or squamous cell carcinoma in-situ.