Imaging Findings in Patients With Benign Adenomyoepithelioma: A Retrospective Analysis

Adenomyoepithelioma (AME) is a rare breast tumor characterized by the biphasic proliferation of epithelial and myoepithelial cells. Due to its rarity, data on its imaging characteristics-particularly magnetic resonance imaging (MRI) findings-remain limited. This study aimed to evaluate the radiological features of AME and assess the diagnostic contribution of multiparametric imaging.

This retrospective study included 11 patients pathologically diagnosed with AME between 2013 and 2024 who underwent mammography, ultrasound (US), and MRI prior to diagnosis. Lesions were evaluated according to BI-RADS criteria: mammography (shape, margin, density, and calcifications); US (shape, margin, orientation, echogenicity, posterior features, vascularity, and elastography); and MRI (morphology, T2 signal intensity, ADC values, and enhancement kinetics).

The most common mammographic finding was an isodense oval or round mass with partially obscured margins (36.4%). No lesions demonstrated irregular shape or suspicious microcalcifications. On US, 90.9% of lesions were oval/round with circumscribed (45.5%) or indistinct (54.5%) margins. All lesions were hypoechoic and vascular; 71.4% exhibited soft elasticity on strain elastography. On MRI, 54.5% were hyperintense on T2 weighted images (T2WI) with circumscribed margins. ADC values ranged from 1.00 to 1.434 × 10^-3 mm²/s (mean 1.273 × 10^-3 mm²/s). Enhancement kinetics demonstrated Type I in 3/11, Type II in 3/11, and Type III in 5/11 lesions.

Although AME often demonstrates benign morphological features, it is frequently categorized as BI-RADS 4 due to vascular and kinetic characteristics that raise suspicion for malignancy. Our findings suggest that relatively low ADC values further contribute to this suspicious imaging profile. However, the absence of suspicious microcalcifications, an oval or round shape, and hyperintensity on T2WI may aid in the differential diagnosis. Given the malignant potential of these lesions, wide local excision with negative margins is essential, and radiological findings play a crucial role in guiding the need for pathological confirmation.