Perineural And Intraneural Involvement In Ductal Carcinoma In-situ Of Breast: Case Report

Abstract Invasion of peripheral nerves by epithelial cells has been traditionally regarded as a feature diagnostic of malignancy, its presence therefore being often sought to document a diagnosis of carcinoma, particularly in the breast. Perineural involvement (PNI) by benign breast disease is not often seen and the etiology is uncertain. The first reported case of nerve invasion in a benign breast lesion was by Ackerman in 1957. Subsequent reports have further confirmed this finding in the breast. The most challenging observation is when the glands involving nerves show cytologic and architectural features of the adjacent atypical duct hyperplasia (ADH) or ductal carcinoma in situ (DCIS). Here, we describe a case of ductal carcinoma in situ grade 2 with nerve involvement in a lumpectomy specimen in a 59-year-old woman. To the best of our knowledge, only five cases of atypical duct hyperplasia by Gobbi et al. and four cases of ductal carcinoma in situ, 3 by Gobi et al. and 1 by Tsang and Chan, associated with nerve involvement, have been reported in English medical literature. Two layers of epithelial cells with the immunohistochemical demonstration of the preservation of a continuous myoepithelial layer in the mammary ducts within the nearby small nerves, is the main clue to confirm the in-situ nature of the inclusions. It is necessary to be aware of this phenomenon in breast lesions to avoid over-diagnosis and inappropriate surgery.