Imaging Manifestation of Adenoid Cystic Carcinoma of the Breast.

Objective: This study aimed to describe the imaging features of adenoid cystic carcinoma (ACC) of the breast using multimode imaging.

Materials And Methods: The findings from mammography, sonography, magnetic resonance imaging, or digital breast tomosynthesis in 11 patients with histopathologically confirmed ACC of the breast were reviewed. The imaging criteria included location, shape, size, number, margin, calcification, attenuation, echo and/or signal intensity, internal mass enhancement pattern, and dynamic-enhancement characteristics.

Results: On mammography (n = 9), ACC demonstrated as an irregular or lobulated mass with indistinct or spiculated margins. Sonographically (n = 11), ACCs appeared as a hypoechoic solid or heterogeneous mass with minimum vascularity on color Doppler examination. With regard to magnetic resonance imaging (n = 9), 2 of the largest masses had an extensive high T2-weighted imaging (T2WI) signal and hypointense internal septations, which demonstrated delayed enhancement. Dynamic enhancement illustrated washout kinetics. The 7 smaller masses appeared isointense on T2WI, and their internal septations were unenhanced. Among them, 5 demonstrated plateau kinetics and 2 demonstrated persistent kinetics.

Conclusions: Although ACC is a rare event in the breast, we believe that the following signs may suggest the diagnosis of this entity: a well-defined border, extensive high T2WI signals, and internal septations that demonstrate delayed enhancement in larger lesions.