Clinical-radiologic-pathologic characterization of diabetic mastopathy: an analysis of 21 cases.

Objective: To characterize the clinic-radiologic features of diabetic mastopathy (DMP), with a focus on distinctive ultrasound findings that may aid in differential diagnosis and reduce unnecessary interventions. Methods: A retrospective multicenter analysis was performed on 21 pathologically confirmed DMP lesions from 17 patients (2014-2024). Mammographic and ultrasonographic features were independently assessed by two radiologists according to the Breast Imaging Reporting and Data System (BI-RADS, 5th edition). Clinical data including diabetes history were reviewed. Results: The median patient age was 58 years, with a median diabetes duration of 23.3 years. Most patients presented with a palpable mass (94.1%). Mammography showed probably benign findings (BI-RADS 3) in 73.7% of lesions, with an additional 10.5% assessed as benign (BI-RADS 2). In contrast, ultrasound revealed suspicious features: all mass-forming lesions had irregular margins (100%), 89.5% showed posterior shadowing, and critically, 78.9% demonstrated an infiltrative growth pattern with an absence of space-occupying effect. One atypical case presented with bilateral ductal dilation. Core needle biopsy yielded a specific DMP diagnosis in only 68.4% of lesions. Surgical excision was performed in 76.2% of lesions, with recurrence in 23.1% during a median follow-up of 33.5 months. Conclusion: DMP presents a diagnostic paradox of benign mammographic but suspicious sonographic appearances. The characteristic "absence of space-occupying effect" on ultrasound is a key differentiating feature from breast carcinoma. Recognizing this sign, along with atypical patterns like ductal dilation, can increase pre-biopsy diagnostic suspicion in patients with long-standing diabetes, potentially guiding more conservative management. Histopathological confirmation remains essential.