Histopathology Report: Sections show predominantly lobules and sheet of mature adipocytes with intervening expansile areas composed of spindle shaped cells with ovoid nucleus with fine chromatin, inconspicuous nucleoli and admixed collagen fibers. There are areas of stromal hemorrhage, myxoid change, dispersed chronic inflammatory cells and fat necrosis. No mammary ductulolobular units or malignancy. Immunohistochemistry ( blocks 2 and 5): The spindle cells are positive for CD34 (Clone: QBEnd10) and negative for Desmin (Clone: D33), SMA (Clone: IA4) and Melan A (Clone: A103).
Final diagnosis: Spindle cell Lipoma with fat necrosis.
Spindle cell lipomas are rare, benign, slow growing tumors. It is a rare variant of breast lipoma.. The common clinical presentation for spindle cell lipomas is painless mobile palpable mass.