Meaning of fat necrosis: Fat necrosis is a benign condition in which damaged fat tissue can form a firm lump that closely mimics cancer on examination and imaging.

Definition of fat necrosis

Fat necrosis is a benign condition in which fat tissue, most often in the breast but occasionally elsewhere in the body, is damaged by injury, surgery, or radiation therapy and subsequently dies. The area of dead fat tissue is often replaced over time by a fluid filled cyst or by scar tissue rather than by normal fat.

Fat necrosis can produce a round, firm lump that is sometimes accompanied by skin changes such as redness, bruising, or dimpling over the affected area, findings that can closely resemble those of breast cancer on physical examination.

Because fat necrosis can also appear similar to cancer on mammography or other breast imaging, distinguishing between the two conditions generally requires a tissue biopsy, particularly when imaging findings are not clearly characteristic of a benign process, since fat necrosis and breast cancer are managed in very different ways despite their overlapping appearance.

Used in a sentence

A biopsy confirmed fat necrosis in the firm lump identified after the patient's prior breast surgery.

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Good to know

Fat necrosis can closely resemble breast cancer on both physical examination and imaging, so a biopsy is often needed to distinguish between the two despite their very different management.

Word origin

Where “fat necrosis” comes from

Necrosis is formed from Greek nekros, meaning dead body, combined with the suffix -osis, meaning condition; fat is an ordinary English word describing the adipose tissue involved.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.