Fat necrosis is a form of

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated diges ...

characterized by the action upon fat by digestive

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

s. In fat necrosis the enzyme

lipase Lipase ( ) is a family of enzymes that catalyzes the hydrolysis of fats. Some lipases display broad substrate scope including esters of cholesterol, phospholipids, and of lipid-soluble vitamins and sphingomyelinases; however, these are usually ...

releases

fatty acids In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated and unsaturated compounds#Organic chemistry, saturated or unsaturated. Most naturally occurring fatty acids have an B ...

from

triglycerides A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester derived from glycerol and three fatty acids (from ''tri-'' and ''glyceride''). Triglycerides are the main constituents of body fat in humans and other vertebrates, as we ...

. The fatty acids then complex with

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar ...

to form

soaps Soap is a surfactant cleaning compound used for personal or other cleaning. Soap may also refer to: Education * Supplemental Offer and Acceptance Program, for medical students who were not initially matched with U.S. residencies by the National ...

. These soaps appear as white chalky deposits.Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; & Mitchell, Richard N. (2007). ''Robbins Basic Pathology'' (8th ed.). Saunders Elsevier. pp. 10-11 It is usually associated with

trauma Trauma most often refers to: *Major trauma, in physical medicine, severe physical injury caused by an external source *Psychological trauma, a type of damage to the psyche that occurs as a result of a severely distressing event *Traumatic inju ...

of the

pancreas The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e. it has both an ...

acute pancreatitis Acute pancreatitis (AP) is a sudden inflammation of the pancreas. Causes in order of frequency include: 1) a gallstone impacted in the common bile duct beyond the point where the pancreatic duct joins it; 2) heavy alcohol use; 3) systemic disea ...

. It can also occur in the breast, the salivary glands and neonates after a traumatic delivery.

Signs and symptoms

Signs and symptoms of fat necrosis are presented below: * masses that seem to be irregular beneath the skin, by touch these should feel smooth and rounded. * tenderness in areas with masses * skin tethering * dimpling * nipple retraction

Causes

Fat necrosis occurs primarily in the

breast The breast is one of two prominences located on the upper ventral region of a primate's torso. Both females and males develop breasts from the same embryological tissues. In females, it serves as the mammary gland, which produces and sec ...

and

. Breast lesions are mostly caused by adipose tissue trauma or post-surgical complications (e.g. hypoxia). Pancreatic lesions arise as a result of the pathological release of pancreatic enzymes which digest surrounding adipose tissue. Fat necrosis is also a feature of some diseases that cause inflammation of subcutaneous fat (panniculitis). Examples of causes include but are not limited to: * Breast trauma (e.g. seat belt injury from a car accident) * Breast surgery ** Fine needle aspiration biopsy and cytology (FNAB, FNAC) **

Radiotherapy Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Rad ...

Lumpectomy Lumpectomy (sometimes known as a tylectomy, partial mastectomy, breast segmental resection or breast wide local excision) is a surgical removal of a discrete portion or "lump" of breast tissue, usually in the treatment of a malignant tumor or brea ...

** Reduction mammoplasty **

Breast reconstruction Breast reconstruction is the surgical process of rebuilding the shape and look of a breast, most commonly in women who have had surgery to treat breast cancer. It involves using autologous tissue, prosthetic implants, or a combination of both wi ...

* Pancreatic disease **

Acute pancreatitis Acute pancreatitis (AP) is a sudden inflammation of the pancreas. Causes in order of frequency include: 1) a gallstone impacted in the common bile duct beyond the point where the pancreatic duct joins it; 2) heavy alcohol use; 3) systemic disea ...

Pancreatic cancer Pancreatic cancer arises when cells in the pancreas, a glandular organ behind the stomach, begin to multiply out of control and form a mass. These cancerous cells have the ability to invade other parts of the body. A number of types of pancr ...

Pancreatic injury A pancreatic injury is some form of trauma sustained by the pancreas. The injury can be sustained through either blunt forces, such as a motor vehicle accident, or penetrative forces, such as that of a gunshot wound. The pancreas is one of the l ...

* Some forms of

panniculitis Panniculitis is a group of diseases whose hallmark is inflammation of subcutaneous adipose tissue (the fatty layer under the skin – panniculus adiposus). Symptoms include tender skin nodules, and systemic signs such as weight loss and fatig ...

** Subcutaneous fat necrosis of the newborn **

Weber–Christian disease Weber–Christian disease, is a cutaneous condition characterized by recurrent subcutaneous nodules that heal with depression of the overlying skin. It is a type of panniculitis. It is a rare disease seen in females 30–60 years of age. It is a r ...

Polyarteritis nodosa Polyarteritis nodosa (PAN) is a systemic necrotizing inflammation of blood vessels (vasculitis) affecting medium-sized muscular arteries, typically involving the arteries of the kidneys and other internal organs but generally sparing the lungs' c ...

Pathophysiology

Fat necrosis is the pattern of damage associated with the destruction of adipose tissue by trauma, hypoxia, or lipase digestion (e.g. pancreatitis). In the classic case of fat necrosis in severe acute pancreatitis, the necrosis arises because

adipocytes Adipocytes, also known as lipocytes and fat cells, are the cells that primarily compose adipose tissue, specialized in storing energy as fat. Adipocytes are derived from mesenchymal stem cells which give rise to adipocytes through adipogenesis. I ...

in the

peritoneum The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of mes ...

are broken and digested by inappropriately activated pancreatic enzymes. Stored

in the adipocytes are released and split by pancreatic lipases into

and

glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...

molecules. The resultant fatty acids react with extracellular calcium to make calcium

(i.e. fatty acid salts) that give fat necrosis its characteristic chalky-white appearance. Fat necrosis is an example of dystrophic calcification because the calcification occurs at normal serum calcium levels. Besides pancreatitis, fat necrosis is also associated with conditions such as

pancreatic carcinoma Pancreatic cancer arises when cells in the pancreas, a glandular organ behind the stomach, begin to multiply out of control and form a mass. These cancerous cells have the ability to invade other parts of the body. A number of types of pancr ...

and pancreatic trauma. Although the peripancreatic region is the most commonly affected site in pancreatic disease (due to direct contact with enzymes), associated fat necrosis can occur around the body in

subcutaneous tissue The subcutaneous tissue (), also called the hypodermis, hypoderm (), subcutis, superficial fascia, is the lowermost layer of the integumentary system in vertebrates. The types of cells found in the layer are fibroblasts, adipose cells, and m ...

, hand and foot joints, and bone marrow. These extrapancreatic complications are known as

pancreatic panniculitis Panniculitis is a group of diseases whose hallmark is inflammation of subcutaneous adipose tissue (the fatty layer under the skin – panniculus adiposus). Symptoms include tender skin nodules, and systemic signs such as weight loss and fatigue ...

. Beyond

saponification Saponification is a process of converting esters into soaps and alcohols by the action of aqueous alkali (for example, aqueous sodium hydroxide solutions). Soaps are salts of fatty acids, which in turn are carboxylic acids with long carbon chains. ...

and

calcification Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature M ...

, fat necrosis concludes with

fibrosis Fibrosis, also known as fibrotic scarring, is a pathological wound healing in which connective tissue replaces normal parenchymal tissue to the extent that it goes unchecked, leading to considerable tissue remodelling and the formation of perma ...

and the formation of grey-yellow

scar tissue Scar tissue may refer to: Medicine * Scar, an area of fibrous tissue that replaces normal skin after injury * Granulation tissue, a product of healing in major wounds Film and television * ''Scar Tissue'' (1975 film), or ''Wanted: Babysitter'' ...

. It is also possible for calcification to occur around the edges of a fatty necrotic lesion, enclosing the fat in a cyst. These "oil cysts" may persist for months to years without undergoing fibrosis. This is often the case in breast fat necrosis, where the underlying oil cysts can be visualised using sonography, X-Ray, CT, or MRI.

Diagnosis

Although fat necrosis can be diagnosed through a routine checkup with a physician, called a physical, a patient can also perform a physical checkup on themselves. For additional diagnosis, a physician would request one or more of the following scans or tests. * CT scan * Mammography test *

Sonography Medical ultrasound includes diagnostic techniques (mainly imaging techniques) using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, musc ...

test * MRI test

Management

When fat necrosis is being felt by a physician or patient, it may feel larger, smaller, unchanged, or not felt at all (resolved). Fat necrosis usually does not require surgery, it usually requires a patient to meet with their physician and as long as the pain is not present there is nothing to be concerned about unless the patient is concerned about cosmetic abnormalities. However, if pain is present surgery is a form of treatment a patient can consider. To keep track of benign fat necrosis a yearly mammogram is taken in order to observe it. However, if fat necrosis consists of oily fluid a physician will go in with a needle to remove this liquid, which may be causing discomfort. Excision may be needed if the mass becomes solid or causes a cosmetic abnormality.

Prognosis

Getting diagnosed with fat necrosis of any kind can be a great cause for concern, as most individuals may mistake it for a malignant tumor. Fat necrosis of the breast is a prognosis that is

benign Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not s ...

and does not increase an individual's risk for various cancers. An individual's life expectancy does not decrease with this diagnosis.

Epidemiology

Fat necrosis in the breast occurs around 0.6%, this represents 2.75% of lesions that end up being

. However, 0.8% of fat necrosis occurs from tumors of the breast, 1% - 9% occurs in

breast reduction Reduction mammoplasty (also breast reduction and reduction mammaplasty) is the plastic surgery procedure for reducing the size of large breasts. In a breast reduction surgery for re-establishing a functional bust that is proportionate to the woma ...

surgery. Individuals that are high risk include women around the age of 50yrs along with pendulous breasts.

References

External links

Fat Necrosis of the breast
{{DEFAULTSORT:Fat Necrosis Pathology Necrosis Breast diseases Pancreas disorders