Ultrasound Findings in Three Complex Cystic Breast Carcinomas: Correlation with Intrinsic Tumor Subtype

In ultrasound examinations, mixed mammary gland masses are divided into either intracystic masses that contain a solid component in the cyst or solid masses that contain a fluid component in the mass. The histological types and subtypes of three complex cystic masses that showed different internal compositions in ultrasound were determined using the ultrasound findings of three patients. Case 1: The mass showed a large cystic component (bleeding) inside and a broad-based solid lesion at the margin in the ultrasound finding. The histological type was encapsulated papillary carcinoma and the subtype was luminal A. Case 2: The mass was lobulated with a small cystic component at the margin. The histological type was solid papillary carcinoma and the subtype was luminal A. Case 3: The mass was lobulated with a circumscribed margin. Cystic components suspected of being hemorrhagic necrosis were observed at the margin and within the solid component. The histological type was squamous cell carcinoma and the subtype was triple negative. Case 2 was a solid mass in appearance, but a cystic component noted at the margin was possibly an intracystic mass. For Case 3, findings suggestive of necrosis were observed both at the margin and in the solid component and this suggested a mass with fluid degeneration. Complex cystic masses are usually examined with a focus on the solid component seen on ultrasound images; however, it is also important to observe the cystic composition. This can help determine the subtypes in addition to the histological types.