Atypical papilloma arising within a benign epithelial inclusion in an axillary sentinel lymph node

Benign epithelial inclusions present in sentinel lymph nodes a diagnostic challenge, particularly at frozen section, and can be mistaken for metastatic malignancy. Heterotopic breast tissue axillary is well documented,1 as its potential proliferative changes including papillomas.2 Also described the concept of iatrogenic cell displacement complication needle procedures contributing to lesions within nodes.3 We describe case report an atypical papilloma arising benign inclusion node. The node was found contain subcapsular circumscribed proliferation comprised acini subtle papillary formations, with focal cribriform architecture mild nuclear atypia. Immunohistochemistry demonstrated myoepithelial cells throughout positive staining epithelium oestrogen receptor. Histopathological examination ipsilateral mastectomy specimen identified extensive papillomatosis foci colonisation by ductal carcinoma situ, single focus invasive mucinous carcinoma. favoured have arisen represent field effect. References 1. Maiorano E, Mazzarol G, Pruneri et al. Ectopic possible cause false-positive biopsies. Am J Surg Pathol 2003; 27: 513–518. 2. Boulos F, Granja N, Simpson J. Intranodal proliferations. 2014; 38: 383–388. 3. Ichihara S, Ikeda T, Kimura K, Coincidence mammary papilloma. 2008; 32: 784–792.