Adenoid Cystic Carcinoma of the Breast Arising in a Lipoma Mimicking Hamartoma: imaging manifestations and review of the literature

Adenoid cystic carcinoma of the breast is a rare neoplasm and only a few articles have described the imaging findings of the disease. We report a 52-year-old woman who presented with a palpable mass beneath the left nipple. Ultrasound revealed a wel l -def ined, lobulated, hypoechoic mass. Mammography demonstrated a radiopaque mass in a well-defined fat-containing lesion, suggestive of hamartoma. The patient underwent surgery due to enlargement of the tumor. The final diagnosis disclosed adenoid cystic carcinoma arising in a lipoma. The unique imaging findings have never been reported in literature. Although adenoid cyst ic carcinoma (ACC) occurs most frequently in the salivary glands and the upper respiratory tract, it is rare in the breasts [1-5]. Mammary ACC accounts for only 0.1-0.4% of all breast carcinomas [3-5]. Its rarity makes it difficult to establish an accurate preoperative diagnosis [4, 6]. The prognosis of mammary ACC is reportedly excellent, with few instances of local recurrence or distant metastasis [3-8]. The medical literature reported only a few cases with imaging and histopathological diagnoses of ACC of the breast [1-7, 9], showing varied radiologic appearance [1-3, 5, 6, 9]. Herein, we report and discuss the imaging and histopathological findings of a patient with ACC of the breast.