Pathologic quiz case: a 62-year-old woman with a 4.5-cm nodule in the right breast. Lipid-rich breast carcinoma.

A woman presented with a hard lump in the right breast and palpable nodes in the right axilla. Mammography and ultrasound disclosed a 4.5-cm, irregular, dense mass with lobulated borders in the upper outer quadrant of the right breast. Results of staging investigation, including chest radiographs and bone scans, were normal. The patient underwent a right modified radical mastectomy with axillary dissection. Gross examination revealed a 4.5-cm, well-circumscribed, lobulated, firm, white-to-yellow tumor. Microscopic examination disclosed a tumor with pushing borders surrounded by and admixed with a massive lymphoplasmacytic and eosinophilic infiltrate (Figure 1). The tumor was characterized by sheets and anastomosing cords of large polyhedral cells with ill-defined borders, fine granular, eosinophilic cytoplasm, and large nuclei with coarse chromatin and prominent nucleoli. These cells were located in the central aspects of the neoplasm (Figure 2), merging imperceptibly with large, clear cells with univacuolated, multivacuolat-