Categorization of fibroepithelial breast tumors according to ultrasound BI-RADS classification

Abstract

Among breast masses, the most common are fibroadenomas (FA), which belongs to the group of a fibroepithelial tumors. Simple pericanalicular FA ordinarily shows the ultrasound signs of a benign mass. Long-standing pericanalicular FA and intracanalicular FA as they grow acquire some ultrasound features uncommon for benign lesions, which requires differential diagnosis with malignant breast masses. The group of fibroepithelial breast tumors also includes phyllodes tumors with frequency of malignant variants of 20–30%. Differential diagnosis of phyllodes tumor and fibroadenomas is difficult, due to the lack of the clear radiologic diagnostic criteria (incl. ultrasound). All breast masses that shows suspicious or atypical features should be selected for biopsy, with the use of BI-RADS classification for the biopsy need indication.Objective: to reveal the rules for fibroepithelial breast tumors categorization according to BI-RADS depending on the ultrasound features.Material and methods. A total of 86 breast masses in 79 women were assessed by ultrasound in B-mode and Color Doppler (CDI). Of these, 22 masses in 15 women showed the typical ultrasound pattern of FA up to 2.0 cm in size with no necessary of morphological evaluation (the average age of the patients was 24.2 ± 5.1 years). Surgery performed for 64 lesions ≥2.0 cm in size, postsurgery morphological examination revealed pericanalicular FA – 38, intracanalicular FA –19 and phyllodes tumors (benign) – 7.Results. The majority of atypical pericanalicular FA (84.2%) were categorized as BI-RADS 4а (a low risk of cancer), 94.7% of intracanalicular fibroadenomas and all phyllodes tumors – as BI-RADS 4b and BI-RADS 4c (а high risk of cancer). The identification of suspicious ultrasound signs led to an increase in the BI-RADS category with indications to the morphological evaluation of the mass.Conclusion. As the suspicious ultrasound signs in B-mode should be considered the irregular shape and borders, vertical orientation and inhomogeneous acoustic shadowing in the absence of macrocalcifications, in Color Doppler – diffuse or focal mass hypervascularity or abnormal vascular pattern. The atypical ultrasound pattern commonly presents in large breast fibroadenomas (>3.0 cm in size), requires differential diagnosis with phyllodes tumors and breast cancer and indicates the need of morphological evaluation and categorizing them as not lower than BI-RADS4.