A 58-year-old woman presents with a firm 2 cm lump in the left breast with mild overlying skin dimpling. Six months ago she sustained a seatbelt injury across the same area. Mammography shows an ill-defined density with coarse calcifications. Cytology shows foamy macrophages and fat globules. What is the most likely diagnosis?

• A Invasive ductal carcinoma
• B Breast cyst with haemorrhage
• C Radial scar
• D Fat necrosis ✓

Explanation

Trauma followed by a firm lump with skin tethering and coarse calcifications is classic for fat necrosis, confirmed cytologically by lipid-laden foamy macrophages and necrotic fat. It matters because it clinically and radiologically mimics carcinoma, so tissue diagnosis is mandatory before dismissing it. Invasive ductal carcinoma would show malignant cells on cytology, a radial scar is an architectural distortion without trauma history, and a haemorrhagic cyst aspirates fluid rather than yielding foamy macrophages.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.