Patient-Level Mass Findings on Mammography and Ultrasonography in Ductal Carcinoma In Situ: Association with Invasive Carcinoma

Background: Preoperative identification of invasive carcinoma in patients with ductal carcinoma in situ (DCIS) remains challenging. While individual imaging findings have been widely investigated, the significance of mass findings identified on both mammography and ultrasonography remains less clearly defined. Methods: This retrospective study included 125 patients with DCIS who underwent both mammography and ultrasonography (US). Imaging findings were categorized as no mass on either modality, mass detected on a single modality, or mass findings identified on both mammography and ultrasonography. Associations between imaging patterns and invasive carcinoma were evaluated using descriptive analyses. Results: The proportion of invasive carcinoma was highest among patients with mass findings identified on both mammography and ultrasonography. Invasive carcinoma was observed in 6 of 71 patients (8.5%) with no mass on either modality, 5 of 37 patients (13.5%) with a mass detected on a single modality, and 8 of 17 patients (47.1%) with mass findings identified on both mammography and ultrasonography. However, substantial overlap between imaging categories remained present. Conclusions: Mass findings identified on both mammography and ultrasonography were more frequently observed in DCIS cases with invasive carcinoma. However, substantial overlap between imaging categories remained present, limiting reliable distinction at the individual patient level.