A large and predominantly cystic breast adenomyoepithelioma in a 35-year-old female: A rare case report and mini review of literature

• Adenomyoepithelioma of the breast is a rare biphasic tumor characterized by epithelial and myoepithelial proliferation. • AMEs usually present as a circumscribed solid mass with rare occurrence of minor cystic changes. • AME with a notable cystic component is extremely rare. • AME usually has a benign course, even though malignant transformation can happen. Adenomyoepithelioma (AME) of the breast is a very rare biphasic tumor composed of epithelial and myoepithelial cells in varying proportions. Usually present as a circumscribed solid nodule, with rare occurrences of cystic or papillary areas. AME with a prominent cystic feature is extremely rare. This case report is aimed at emphasizing that AMEs can entirely be cystic, so that radiologists and pathologists should consider it as a possibility whenever they encounter a cystic breast lesion. A 35-year-old woman presented with a painful breast lump of six months’ duration. A breast ultrasound scan revealed a 9 cm multilocular cystic mass with a focal area of solid masses arising from the cyst wall projecting into the cyst cavity. Initial fine needle aspiration cytology (FNAC) was non-diagnostic since the aspirate was only cyst content. Later the ultrasound-guided FNAC suggested AME. Complete excision of the mass with a wide margin was done, and subsequent histopathologic examination and immunohistochemistry confirmed the diagnosis of benign AME with free margins. Even though it is extremely rare, AME may appear predominantly cystic with a focal solid area. Preoperative FNAC should be done with ultrasound guidance to make sure the solid area is sampled. AME should be considered in the list of differential diagnoses for cystic breast lesions.