[Hematoma and fat necrosis of the breast: mammographic and echographic features]

The mammary gland is a common site for traumas which often lead to the formation of intraglandular hematomas. The abundance of fat tissue in this gland accounts for the relatively high frequency of fat necrosis and self-digestion of fat by lipases after traumas, i.e., fat necrosis, cystosteatonecrosis, lipophagic granuloma. Broadly speaking, hematomas are easily diagnosed by both mammography and US. However, scarring and the formation of lipophagic granulomas due to hemorrhage result in the diagnostic features which are difficult to distinguish from malignant breast nodules. In our study, we examined 40 patients with a clinically detected nodule and/or hematoma with skin retraction or thickening related to trauma. In 26 women, the trauma dated to 7-60 days before our observation, in 4 women to a year before and in 4 other women to more than two years before; 6 women had undergone breast surgery in the last two years. Mammography and US were performed at first observation; later, every six months, the patients were followed-up with US and a single targeted radiograph. The mammographic features at first observation were classified as follows: a single nodule (9 patients, 22.5%), a patchy nodule (7 patients, 17.5%), diffusely increased gland density (8 patients, 20%), radiolucent nodules (10 patients, 25%), nodules with calcifications (6 patients, 15%), no findings (2 patients, 5%). US demonstrated a fluid collection in 12 patients (30%), a solid nodule in 6 patients (15%), a cystic nodule in 10 patients (25%), diffuse parenchymal abnormalities in 4 patients (10%), calcified nodules in 6 patients (15%) and no findings in 2 patients (5%). US-guided needle biopsy was performed in 10 patients. Five patients underwent surgical biopsy: 4 had a lipophagic granuloma and the other one a chronic inflammation. Follow-up at two years allowed hematoma evolution to a scar or cystosteatonecrosis to be monitored. To conclude, the authors analyze the diagnostic problems related to the different mammographic and US patterns trying to suggest, on the basis of their own experience, the best imaging follow-up for breast trauma patients.