Mammography and Digital Breast Tomosynthesis in Granulomatous and Nongranulomatous Mastitis

Digital Mammography (DM) is extensively used for breast imaging however, lesion visibility is often limited by overlapping tissues, which affects lesion characterization. Digital breast tomosynthesis (DBT) reduces the effect of overlapping tissues and helps in revealing obscured findings. We aimed to describe the mammographic findings in granulomatous and non-granulomatous mastitis and assess the utility of adjunctive DBT in lesion characterization.

DM and DBT images of histo-pathologically diagnosed cases of granulomatous (GM) and non-granulomatous mastitis (NGM) were reviewed according to the BI-RADS lexicon. Presence of contiguous/ interconnected lesions, tubular densities, interspersed hypodensities/fat densities within the involved areas were also assessed. The perceived utility of adjunct DBT was scored from 0-2.

Of 33 reviewed patients (24 GM, 9 NGM; median age 39 years, range 24-78); 13/33 (39.4%) were under 35 years of age. DBT detected masses in 24/33 (72.7%), whereas only 15/33 (45.4%) were visible on DM alone. Contiguous or inter-connected lesions were found in 10/33 (30.3%) cases. Tubular extensions were seen in 14 cases and interspersed hypodensities in 15. None of the enlarged lymph nodes had irregular shape or indistinct margins or loss of fatty hilum. DBT was able to categorize more lesions as BIRADS 4a or below, as compared to DM alone.

Mammographic presence of multiple contiguous iso-dense masses, reniform contour of axillary lymph nodes with preserved fatty hilum despite a large area of breast involvement favour a benign etiology; especially if DBT reveals tubular extensions or lesions with inhomogenous low density areas within.