The gross appearance of fat necrosis is as an irregular, chalky white area within otherwise normal adipose tissue.

The necrotic tissue may eventually form a palpable mass (especially if situated at a superficial site like the breast).

[3] Traumatic fat necrosis commonly affects the breast and may resemble a tumour (especially in case of calcification of the necrotic mass).

[3][2] Although the peripancreatic region is the most commonly affected (due to direct contact with enzymes), associated fat necrosis may occur throughout the body in subcutaneous tissue, hand and foot joints, and bone marrow.

[5] Examples of causes include but are not limited to:[citation needed] Fat necrosis in the breast occurs around 0.6%, this represents 2.75% of lesions that end up being benign.