Clustered Microcysts on Breast Ultrasound: What Is an Appropriate Management Recommendation?

Objective: The objective of our study was to determine outcomes of lesions identified as clustered microcysts on breast ultrasound to augment the existing literature and help guide appropriate management recommendations.

Materials and methods: We retrospectively identified cases at our institution, from January 2003 through December 2013, of all lesions classified as clustered microcysts at breast ultrasound. Breast ultrasound examinations were performed by the interpreting physician. If ultrasound-guided sampling was performed, results were obtained from the pathology or cytology reports. If sampling was not performed, only lesions with at least 24 months of imaging follow-up or any imaging follow-up with interval resolution or decrease in size were included in the study. Outcomes and frequency of malignancy were determined by reviewing the electronic medical records and our PACS.

Results: Of 144 patients with 148 lesions classified as clustered microcysts on ultrasound, 93 patients with 95 lesions had adequate follow-up and were included in our study population. The mean patient age was 50 years (range, 32-72 years). Of the 16 lesions that underwent percutaneous sampling, none (0% [95% CI, 0-21%]) yielded malignancy. Fourteen (88%) sampled lesions were benign, and two (12%) of the sampled lesions revealed atypical ductal hyperplasia at percutaneous sampling but no atypia or upgrade at subsequent surgical excision. In total, 0 of 95 lesions (0% [95% CI, 0-3.8%]) showed malignancy at sampling or imaging follow-up.

Conclusion: Our results support that lesions sonographically characterized as clustered microcysts carry an extremely low risk of malignancy, and biopsy should be avoided.