Mucinous breast carcinoma showing as a cluster of suspicious microcalcifications on mammography

We report a case of mucinous breast carcinoma whose mammographic features consisted of a suspicious cluster of microcalcifications as the unique sign of malignancy. The lesion was non-palpable and measured approximately 2 cm at the greatest diameter. The microcalcifications showed several morphologies: round, pleomorphic, and fine shapes were identified. The total number of microcalcifications was > 30 and the number per square centimeter varied from 10 to 20. The histological calcifications showed good correlation with the mammographic ones and were localized predominantly at the periphery of the tumor inside ducts with ductal carcinoma in situ or in the acellular mucin. Two types were observed: psammomatous and gross-irregular calcifications. To our knowledge, only one case with similar findings has been reported previously.