Fat Necrosis

Fat necrosis is the type of necrosis in which adipose tissue or fat is broken down into fatty acids and glycerol. Then fatty acids react with metallic ions, e.g., Na, K, Ca and produce soap-like compounds. These compounds are not dissolved in fat solvent and remain in adipose tissue. 

Fat necrosis occurs in-

•      Udder,

•      Subcutaneous tissue.

Causes:

Two mechanisms are involved in causation of fat necrosis-

1.      Pancreatic fat necrosis and

2.      Traumatic fat necrosis.

1. Pancreatic fat necrosis:

Pancreatic fat necrosis occurs in abdominal cavity. Here, pancreatic lipase enzyme escaping from pancreatic duct acts over the adipose tissue causing fat necrosis. The duct is usually broken down due to either tumor or severe inflammation in the duct.

2. Traumatic fat necrosis:

Traumatic fat necrosis occurs in subcutaneous adipose tissue due to trauma.

Gross lesions:

•      The fat becomes solid, opaque, whitish in colour and loses shiny appearance.

Microscopic lesions:

•      Fat in lipocyte is replaced by soap. So, there is presence of homogenous either bluish or pink or purple mass within the fat cells.

           If it is Na soap, colour is bluish.

            If it is K soap, colour is pink.

            If it is Ca soap, colour is purple.

•      The nuclei of the cells are pyknotic

Significance:

•      Pancreatic fat necrosis has the significance in meat inspection indicating severe inflammation or presence of tumor.

•      Traumatic fat necrosis has the significance in forensic pathology.