Breast plasmacytoma

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.