Carcinoma in a solitary intraductal papilloma of the breast

Herein is reported a rare case of carcinoma arising from papilloma of the breast. A 63‐year‐old postmenopausal woman noticed a nodule approximately 1 cm in diameter in her left breast. Ultrasonography indicated a mass with a solid pattern within an intracystic tumor measuring 1.5 × 1.5 × 1.4 cm in diameter located near the left nipple. On total image analysis malignancy could not be denied, therefore lumpectomy with resection of the surrounding tissue was performed. Histologically the tumor consisted of cancerous and papilloma components. The cancer cells had high‐grade nuclear atypia, were irregular, and contained abundant eosinophilic cytoplasm with a thin vascular stalk. In contrast, the tumor cells had no atypia, and had a thick stroma in the papilloma components. Both lesions could be distinguished clearly from each other. In addition, a transition from papillary to cancerous elements in some areas was seen. An additional partial mastectomy was performed after the lumpectomy but no carcinoma foci were noted in the excised tissue. Possible occurrence of cancerous change in solitary intraductal papilloma of the breast was suspected.