From the Guidelines
A1 and A2 fat necrosis is a classification system for fat necrosis based on the presence of calcifications, with A1 representing non-calcified fat necrosis and A2 indicating calcified fat necrosis, and management is generally conservative unless there are concerning features requiring biopsy to exclude malignancy. Fat necrosis is a benign inflammatory process that occurs when fatty tissue is damaged, often due to trauma, surgery, or radiation therapy. In A1 fat necrosis, the damaged adipose tissue undergoes necrosis but has not yet developed calcifications, typically appearing as an ill-defined mass or area of increased density on imaging 1. A2 fat necrosis has progressed to develop calcifications within the necrotic fat, which may appear as coarse, irregular, or dystrophic calcifications on mammography. These calcifications develop as calcium salts deposit in the damaged tissue during the healing process.
Some key points to consider in the management of A1 and A2 fat necrosis include:
- The importance of clinical judgment in diagnosis, as imaging studies may not always be diagnostic 1
- The use of imaging modalities such as CT or MRI to evaluate the extent of fat necrosis and to exclude other conditions 1
- The need for biopsy to exclude malignancy in cases with concerning features 1
- The generally conservative management approach, with surgical intervention reserved for cases with significant symptoms or complications 1
It is also important to note that fat necrosis can be associated with other conditions, such as alpha-1 antitrypsin deficiency, which can increase the risk of developing necrotizing panniculitis 1. However, the management of A1 and A2 fat necrosis is generally focused on relieving symptoms and preventing complications, rather than treating an underlying condition. Overall, the key to managing A1 and A2 fat necrosis is a conservative approach, with careful monitoring and prompt intervention if necessary to prevent complications and improve outcomes.
From the Research
Fat Necrosis Overview
- Fat necrosis is a benign non-suppurative inflammation of the adipose tissue, which can mimic breast cancers and pose a diagnostic challenge for clinicians and radiologists 2.
- It has various appearances on different imaging techniques, including oil cysts, benign dystrophic calcifications, indeterminate focal asymmetries, architectural distortions, and masses 2.
Causes of Fat Necrosis
- Fat necrosis can be caused by trauma, including intramuscular injections 3.
- It may also be associated with other conditions, such as pancreatic disease 3.
- Nonsteroidal anti-inflammatory drugs (NSAIDs) have been linked to necrotising fasciitis, but a causal relationship between NSAIDs and fat necrosis cannot be established 4.
Management of Fat Necrosis
- Asymptomatic or small lesions can be treated conservatively 5.
- Oil cysts and moderately sized areas of symptomatic fat necrosis can be effectively treated by aspiration, ultrasound-assisted liposuction, or needle aeration 5.
- Calcified and large areas of fat necrosis require excision and debridement of necrotic fat tissue 5.
- A step-up approach, including percutaneous drainage, endoscopic transmural drainage, and surgical debridement, may be used to manage pancreatic necrosis, but its application to fat necrosis is unclear 6.