ruptured and discharged contents into the surrounding stroma [1]. Previous reports on the imaging findings of mucocele-like tumors described no specific findings to discriminate mucocele-like tumors associated with and those not associated with ADH or malignancy [5-7, 9, 10]. It has been suggested that on mammograms, mucocele-like tumors associated with malignancy have microcalcifications more frequently and to a greater extent than do benign mucocele-like tumors [7,11]. Two reports [12,13] have described attempts to differentiate benign and malignant cystic lesions in various pathologic conditions.The purpose of our study was to review the mammographic and sonographic findings of mucocele-like tumors and to correlate the imaging findings with the pathologic findings. A secondary purpose was to evaluate the differential radiologic findings of pure mucocelelike tumors and mucocele-like tumors associated with ADH or malignancy of the breast Because mucocele-like tumors may be associated with these other conditions, it is difficult to differentiate a pure mucocele-like tumor from a malignant tumor with fine-needle aspiration or core needle biopsy findings, and complete excision is recommended [5][6][7][8][9].
Wo m e n's I m ag i ng • O r ig i n a l R e s e a rc hDescriptions of sonographic findings of mucocele-like tumor are limited, and fewer than 20 cases have been described [7,9]. A mucocele-like tumor has been described as a cystic mass [7,9], a finding that correlates with the pathologic finding of mucocele-like tumors as multiple cysts of mucinous material that have
W O M E N ' S I M A G I N GOBJECTIVE. The purpose of this study was to evaluate the differential radiologic findings of pure mucocele-like tumor and mucocele-like tumor associated with atypical ductal hyperplasia (ADH) or malignancy of the breast according to BI-RADS and sonographic cystic mass classification.MATERIALS AND METHODS. During a 10-year period, 72 mucocele-like tumors in 68 women were diagnosed histologically at three institutions. We retrospectively reviewed the mammographic (n = 69) and ultrasound (n = 72) findings of the 72 lesions according to the BI-RADS lexicon. The radiologic findings were correlated with the pathologic results.RESULTS. Mammography showed 53 lesions had calcifications without (n = 39) or with (n = 14) a mass. Calcifications of intermediate concern or associated with higher probability of malignancy were found more frequently in mucocele-like tumors associated with ADH or malignancy than in pure mucocele-like tumors (92.3% vs 62.9%, p = 0.019). At ultrasound, 69 of the mucocele-like tumors (95.8%) were seen as a cystic mass. Cysts with thick septations, clustered cysts, and complex masses were more frequently seen in mucocele-like tumors associated with ADH or malignancy (89.7% vs 32.5%, p < 0.001). The positive predictive value for BI-RADS category 4 was 13.3% (95% CI, 6.9-24.2%) and was 50% for BI-RADS category 5 (95% CI, 15-85%).CONCLUSION. Mucocele-like tumors associated with ADH or malignancy were more fre...