Background: Breast plasmacytoma (BP) is extremely rare. The published data on this manifestation include predominantly case reports and do not provide any statistical information.
Purpose: To identify clinical signs and radiological features of BP.
Material and Methods: Five patients with BP were retrospectively identified in the pathological and radiological databases of the years 1997–2009 at our institution. Additionally, 48 patients were collected from the literature in the period from 1988 to date. Therefore, our study involves 53 patients.
Results: The prevalence of BP in our institution was 1.5% of all identified cases with plasmacytoma and 0.2% of the cases with breast cancer. In 8 of 53 patients (15%), primary BP was diagnosed, and in 45 patients (85%) involvement of the breast was a secondary event of the multiple myeloma (MM). Clinically, 83% of the patients presented with breast lumps. BP was diagnosed incidentally in 9%. In 8% of the cases clinical signs were not reported. On mammography, intramammary round or oval masses were most commonly found (89%). They were solitary in 66% of the cases and multiple in 34%. Median size was 21 mm, ranging from 8 to 90 mm. In 9% of the identified cases BP manifested as diffuse infiltration of the breast. In 2% no abnormalities were identified on mammography. On ultrasound, identified lesions were homogeneously echo-poor or hypoechoic, less frequently mixed hypo- to hyperechoic. Treatment of BP is the same as for other localizations of plasmacytoma and is based on chemotherapy and/or radiotherapy. Primary BP had a better prognosis than breast involvement as a secondary event in MM.
Conclusion: In conclusion, BP does not have specific radiological or clinical features and can be misdiagnosed as primary breast carcinoma or even as a benign process. However, BP should be considered in the differential diagnosis of breast disorders, especially in patients with MM.
