A Rare Breast Tumor Presenting As Adenomyoepithelioma With Suspicious Imaging Features: A Case Report

Adenomyoepitheliomas (AMEs) are rare breast neoplasms often detected incidentally during routine screening mammograms in asymptomatic females. Clinically, AMEs usually present as a palpable, solitary mass, though they may also be discovered during routine imaging. Radiologically, AMEs exhibit variable features. Mammography findings may include round or lobulated masses with circumscribed or indistinct margins, occasionally accompanied by microcalcifications. On ultrasound, they typically appear as solid, hypoechoic, irregular, or oval masses with microlobulated margins, while color Doppler may demonstrate internal hypervascularity. However, these imaging characteristics are nonspecific and can mimic other breast lesions, including malignancies. Histologically, AMEs are defined by a biphasic proliferation of epithelial and myoepithelial cells, with patterns such as spindle cell, tubular, and lobular variants. Immunohistochemical staining plays a crucial role in diagnosis, with markers such as p63, calponin, and smooth muscle myosin heavy chain being positive. Atypical features, including nuclear pleomorphism, mitotic activity, and necrosis, should prompt suspicion for malignancy. The primary treatment for AMEs is complete surgical excision with clear margins to reduce the risk of recurrence. Incomplete tumor removal is associated with a higher likelihood of local recurrence. Malignant transformation of either cellular component is rare but has been reported, with metastases to the lungs, brain, and thyroid. Malignant AMEs are characterized by significant cytologic atypia and high mitotic rates. Studies suggest that larger tumors with infiltrative margins carry an elevated risk of recurrence and metastasis. In this case report, we present a case of a 42-year-old female who presented for a routine screening mammography with a subsequent breast ultrasound and was found to have a suspicious mass that was pathologically proven as benign AME.