Mucinous carcinomas of the breast: imaging features and potential for misdiagnosis.

Introduction: Pure mucinous breast carcinomas (PMBC) are commonly lobulated, therefore appear relatively benign compared with the imaging features of invasive ductal carcinoma. The aim of this study was to determine mammographic and sonographic patterns of PMBC, in particular features that may result in misdiagnosis.

Methods: Retrospective review of available mammography and sonography in 90 patients diagnosed with PMBC within the Monash BreastScreen service, 1993-2011 inclusive.

Results: PMBC commonly have indistinct or lobulated mammographic and sonographic margins. Mammographic calcifications are absent in the majority (82%). On ultrasound, these neoplasms are commonly isoechoic (51%) with normal posterior acoustic appearances (80%). However, most (77%) of these lesions have suspicious or definite imaging features of malignancy.

Conclusion: PMBC are commonly lobulated with homogeneous, isoechoic and normal posterior acoustic sonographic appearances but rarely have benign imaging features.