Characterization of Sonographic and Mammographic Features of Granular Cell Tumors of the Breast and Estimation of Their Incidence

Objective. The purpose of this series was to review the spectrum of sonographic and mammographic features of granular cell tumors (GCTs) of the breast and to compare their frequency relative to breast carcinoma. Methods. Ten cases of a breast GCT diagnosed during the last 13 years were analyzed for the imaging characteristics and clinical features. Sonographic images were reviewed for location, size, echogenicity, margins, height‐width ratio, and sound transmission. Mammograms were reviewed for tumor size, location, margin characteristics, spiculations, and calcifications. The frequency of GCTs was compared with that of breast carcinoma during the same study period. Results. Of 10 GCT cases, 9 tumors occurred in female patients, and 1 occurred in a male patient. The mean patient age was 51.8 years, and the mean lesion size was 1.57 cm. All 7 tumors visualized on sonography were hypoechoic masses. Posterior enhancement was noted in 3 of 7 cases, and posterior shadowing was noted in 2 of 7 cases. Two of 7 did not show any posterior enhancement or shadowing. Two of 7 masses were taller than wide. Of 8 tumors visualized on mammography, 5 were spiculated, and 3 were well circumscribed. Calcifications were not visualized in any tumor. During the same period, 1482 cases of breast carcinoma were diagnosed, making the frequency of GCTs of the breast about 6.7 per thousand breast carcinomas. Conclusions. Granular cell tumors of the breast are rare neoplasms with a relative frequency of 6.7 per thousand breast carcinomas in our series, which was higher than reported in literature. Spiculations are a common imaging feature and mimic carcinoma when present.