A Challenging Case of Atypical Papillary Proliferation of Nipple with Loss of Myoepithelial Layer Cells; a Diagnostic Dilemma

Abstract Introduction/Objective Papillary breast lesions are comprised of a broad spectrum entities ranging from benign conditions like intraductal papilloma to invasive carcinoma. These account for less than 3% percent tumors and 2% malignancies. The wide range overlap in the clinical, imaging, histologic characteristics these can often make them difficult classify. Here we present case challenging neoplastic nipple papillary lesion with differential diagnosis adenoma atypia Methods/Case Report 48-year-old female history left mass 6 months, presented emergency department mild bleeding two hours. Breast ultrasound showed group fine pleomorphic calcifications within arising nipple, highly concerning Paget's disease. Histopathology revealed proliferation well-formed round structures variably fibrous/hemorrhagic stroma. nodules exhibited fronds epithelial hyperplasia monotonous low-grade cells, scattered mitoses, forming relatively rigid/luminal polarization. No desmoplasia or conventional infiltrative pattern was seen. Immunohistochemical staining strong expression estrogen receptor (ER). Cytokeratin 5/6, p63 calponin did not highlight myoepithelial layer elements around structures. A atypical rendered warrant an excision. Subsequently, patient underwent total mastectomy, which ductal carcinoma lymphovascular space invasion. Results (if Case Study enter NA) NA Conclusion Atypical classify limited biopsy material. loss cell makes interpretation even more challenging. Extreme caution should be taken assigning nature eventually guide surgeon making decision preserve not.