| Fat necrosis | |
|---|---|
| Other names | also known as Balser's necrosis |
 | |
| Micrograph of breast tissue showing fat necrosis.H&E stain | |
| Specialty | Pathology |
Fat necrosis isnecrosis affectingfat tissue (adipose tissue).[1] The term is well-established in medical terminology despite not denoting a specific pattern of necrosis.[2] Fat necrosis may result from various injuries to adipose tissue, including: physical trauma, enzymatic digestion ofadipocytes bylipases,[3]radiation therapy,[4]hypoxia, orinflammation of subcutaneous fat (panniculitis).
The gross appearance of fat necrosis is as an irregular, chalky white area within otherwise normal adipose tissue.[1]
Traumatic injury of adipose tissue liberates stored fat[1][3] as well as lipases[1] fromadipocytes. The extracellular fat then elicits a swift inflammatory response, attractingmacrophages andpolymorphonuclear leukocytes which proceed to phagocytose the freed fat. The process eventually leads tofibrosis. 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).[1]
Pancreatic conditions like acute pancreatitis,[3]pancreatic carcinoma, andpancreatic trauma[5] result in liberation ofpancreatic lipase which proceeds to digest fat to form free fatty acids which subsequently combine with calcium to formsoapy precipitates.[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 insubcutaneous tissue, hand and foot joints, and bone marrow. These extrapancreatic complications are known aspancreatic panniculitis.[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 beingbenign. However, 0.8% of fat necrosis occurs from tumors of the breast, 1–9% occurs inbreast reduction surgery. Individuals that are high risk include women around the age of 50yrs along with pendulous breasts.[8]