A case of mutiple myeloma of the breast mimicking an inflammatory carcinoma

We report af case of breast lesion, with clinical and radiological features of inflammatory carcinoma. It turns out to be the first symptom of Multiple Myeloma.
A 92-year-old woman presented with a swelling on her left breast. Clinical examination revealed an erythematous and edematous breast. Mammography showed a large tumour with 16cm. An ultrasound-guided core needle biopsy was performed.
Histological examination shows extensive infiltration of biopsies by tigthly packed immature cells with round cells with wide eosinophilic cytoplasm and prominent nucleoli. Immunohistochemistry revealed positivity for CD138, Kappa light chain, and negativity for Lamda light chain, CD56, Bcl-2, CD3, CD20, CD30, A1/A3 and Gata3. Ki-67 was positive in 100%. These findings corroborated the diagnosis of plasmacytoma of the breast. An extensive search for multiple myeloma was performed and radiology revealed multiple masses throughout the skeletal system.
The involvement of breast by multiple myeloma has been rarely reported. Until now 21 cases have been described.
Most frequent symptom is a palpable mass. When there is orange peel like texture of the skin, suggests inflammatory carcinoma. The differential diagnosis includes plasma cell mastitis, primary epithelial neoplasms of the breast, non-Hodgkin's lymphoma with plasmacytic features and epithelioid malignant melanoma.