Xanthogranulomatous Breast Mass: An Unusual Presentation.

Xanthogranulomatous inflammatory reactions are benign inflammatory processes characterized by aggregating lipid-laden foamy macrophages. Although cases have been reported in different organ systems, these rare reactions predominantly occur in the kidney and gallbladder. We present a 92-year-old female who noticed a palpable, tender mass in the lower inner quadrant of her right breast with no skin changes. She was referred to surgery by her primary care physician on suspicion of malignancy and further evaluation. Ultrasound-guided biopsy, ordered by the primary care provider, revealed a suspicious high-grade malignant neoplasm of uncertain origin. Pathological findings include the presence of an unusual population of malignant epithelioid cells with a striking xanthogranulomatous reaction, along with numerous Touton-like histiocytes. These findings are comparable in morphology to a recently reported xanthogranulomatous epithelial tumor. Given the lack of history of breast carcinoma in this patient as well as the lack of immunohistochemical studies suggesting breast carcinoma, treatment involved continuing standard of care for an unusual high-grade sarcoma via lumpectomy. A positron emission tomography (PET) scan was ordered to ensure there was no spread or alternate origins of the cancer tissue. This case report brings to light the findings of a probable xanthogranulomatous tumor in breast tissue, an exceptionally rare phenomenon in breast cancer, especially in the elderly population. Due to the rarity of xanthogranulomatous tumors in the breast, prognosis and standardized treatment have yet to be established.