Breast AMEs are rare neoplasms. They have been described in patients ranging in age from 22 to 93 years [
6], although most of them were elderly women, male cases were also reported [
7]. AMEs are generally benign neoplasms, although a small number of malignant lesions have been reported in the literature, either the epithelial or myoepithelial component may undergo malignant transformation [
8]. Some papers have concluded that AMEs over 2 cm should be treated as malignant [
9]. Most of AMEs were solid, prominent cystic features of this tumor was extremely rare, in spite of rare minute cysts were described in a few cases of AMEs. A review of the literature indicates that only one case of cystic AME has been reported [
10]. In our case, the patient had a large lesion with persistent breast pain. Although the lesions had prominent cystic changes, the boundary of some lesions was unclear, and she did not receive any further treatment after the surgery. It is important for the surgeon to achieve a clear margin when removing the tumor, because local recurrence or even malignant transformation can happen. So the patient still needed to be followed up to observe if malignant transformation occur after local lesion resection. Up to now, the patient has been followed up for half a year without recurrence or discomfort, and re-examination of ultrasound showed no abnormality. The radiological findings of breast AME are nonspecific. On ultrasound, AME typically presents as a solid, hypoechoic, small, irregular, or oval mass, often accompanied by posterior acoustic enhancement. Peripheral vascular enlargement has some features, and the mass may have catheter dilation [
11,
12]. Mammography is usually characterized by a noncalcified ovoid or lobulated mass with smooth margins [
13,
14]. MRI can provide additional information on the morphological and haemodynamic characteristics. On MRI, benign AMEs manifest as homogeneous signal on different sequences with Type I or II enhancement curves, while malignant AMEs presented as irregular and coarse-edged masses with type III enhanced curve [
12,
15]. In our case, ultrasonography showed a lobulated mass with prominent cystic changes in the right breast, which was significantly different from the stereotypical AME images. Mammography shows a noncalcified lobulated mass, which is not significantly different from the common AME imaging findings due to the poor performance of the cystic changes on mammography. The prominent cystic features of the present tumor was easily misdiagnosed, so it’s needed to be distinguished from ductal carcinoma of breast, adenoid cystic carcinoma, lobulated tumor, cyst of galactostasia, metaplasia carcinoma, etc. The imaging findings of these tumors did not differ significantly.
AME of breast is a rare and mostly benign tumor. AME has no-specific imaging features, but the benign or malignant nature of the lesion might be suspected on imaging.