Echogenic Rind as an Independent Diagnostic and Prognostic Marker of Malignancy

Echogenic rind has been incorporated into the BI-RADS v2025 ultrasound lexicon as an associated feature of masses; however, its utility as an independent diagnostic and prognostic marker of malignancy has not been well established. This retrospective study compares the imaging and phenotypic features of biopsy-proven malignant masses with and without an echogenic rind to assess its utility as an imaging marker.

Consecutive patients with biopsy-proven malignant masses were placed into separate cohorts based on the presence/absence of an echogenic rind. An echogenic rind was defined as an ≥1 mm echogenic band that surrounded at least 25% of the mass circumference and disrupted adjacent tissue. Imaging characteristics (size, shape, margins, orientation), tumor type (ductal carcinoma in situ [DCIS], invasive ductal carcinoma, and invasive lobular carcinoma), receptor status, and Nottingham grades of masses in both cohorts were compared using Fisher's exact test and multivariate analysis. A separate cohort of consecutive patients with biopsy-proven DCIS presenting as masses was then reviewed to assess the proportion of masses with an echogenic rind and upgrade to invasive malignancy on surgical pathology.

Masses with an echogenic rind were associated with invasive breast cancer (P = 0.001) and had higher upgrade rates when core biopsy revealed DCIS (P = 0.04). Masses in both cohorts did not vary by size (P = 0.41), shape (P = 0.44), or margin (P = 0.62), or demonstrate significant differences in receptor status (P = 0.98) or Nottingham grade (P = 0.85).

Presence of an echogenic rind surrounding a mass is associated with invasive malignancy and correlates with upgrade of DCIS to invasive cancer on surgical pathology but otherwise offers minimal additional diagnostic or prognostic utility to radiologists.