Value of Ultrasonographic Features for Assessing Malignant Potential of Complex Cystic Breast Lesions.

OBJECTIVES: To assess the value of ultrasonography (US) features for determining the malignant potential of complex cystic lesions. METHODS: Seventy-nine complex cystic lesions were reviewed retrospectively. They were classified into four types according to US features in type I, the masses have a thick outer wall, thick internal septa, or both; in type II, the masses are an intracystic type with one or more discrete solid mural lesions within a cyst; in type III, the masses contain mixed cystic and solid components and are at least 50% cystic portion in a mass; in type IV, there are predominantly (at least 50%) solid masses with eccentric or central cystic foci. Positive predictive values were calculated for all types. RESULTS: The frequency of malignancy was higher among type III and IV lesions than among the other two types. Lesions with a diameter greater than or equal to 20 mm, margins not circumscribed, resistance index greater than or equal to 0.7, and axillary abnormal nodes had a high probability of malignancy. CONCLUSIONS: US is an important adjunct to evaluate the malignant potential of complex cystic lesions.