Breast cysts with masses versus breast masses with cysts: Sonographic sub-types of complex breast cysts with pathologic correlations

Abstract

Background: Cystic lesions of the breast are generally classified as simple, complicated or complex. A complex breast cyst is however defined as a lesion which contains both cystic (anechoic) and solid (echogenic) components. There is a need to understand the sonographic criteria and differential diagnoses of complex cysts which have varying risks of malignancy, as against simple or complicated cysts which are typically benign. Objectives: To examine the sonographic subdivisions of complex breast cysts, correlating with histopathological diagnosis as seen in Ahmadu Bello University Teaching Hospital, Zaria. Materials and Methods: A 5-year retrospective review of 106 women who had complex breast cysts diagnosed on high resolution ultrasound (Mindray DC- 8, 2013; transducer frequency 7.5–12 MHz). The lesions were categorized as: Type 1 (cysts with thick wall or septa), Type 2 (cysts with a small mural nodule), Type 3 (cystic and solid lesion with >50% cystic component), Type 4 (cystic and solid lesion with >50% solid component). The final diagnosis was either by short term ultrasound follow-up, Ultrasound-guided fine needle aspiration cytology/core biopsy or excision biopsy. Results: Out of a total of 248 patients with breast cysts, 106 women had complex cysts. 27 (25.4%) patients had cysts with either thick wall or septa or both; 11 (10.4%) had a small intra-mural nodule; 14 (13.2%) had solid-cystic mass with >50% cystic component and 54 (50.9%) had solid-cystic mass with >50% solid component. Overall 66% were benign while 34% were malignant. The commonest pathology to present as a complex breast cyst was invasive ductal carcinoma not otherwise specified. Conclusion: Complex cysts are associated with varying risks of malignancy. Also, a certain pathology could exhibit sonographic features of any of the subdivisions (Type 1-4). Therefore, meticulous attention should be paid to other associated imaging findings as well as detailed history and thorough clinical examination.