Breast Fat Necrosis

Excerpt

Breast fat necrosis is nonviable adipose cells from injured or ischemic breast tissue that is replaced with scar tissue and presents as a palpable nodule. Breast fat necrosis has various etiologies and implications; therefore, a careful patient history is imperative to properly evaluate the patient. The most common etiology of fat necrosis is recent breast surgery; however, in non-operative patients, cancer or mechanical trauma to the breast tissue is often the culprit. Breast fat necrosis can be confusing on breast imaging with malignancy (it can mimic malignancy on radiologic studies, as well as clinical presentation). It can also be cosmetically undesirable. In this article, we will focus on breast fat necrosis in the surgical patient.

Anatomy

Three structures comprise the breast: skin, subcutaneous tissue, and breast tissue. The breast tissue contains both epithelial and stromal elements, the latter being both adipose and fibrous connective tissue. Stromal elements are responsible for the majority of breast volume during the non-lactating state.

The majority of the blood supply to the breast comes from the internal mammary artery perforators and the minority from the lateral thoracic artery perforators. This factor is essential, especially during breast reduction and/or reconstruction, where transection of vessels and subsequent relative ischemia can lead to breast fat necrosis.

Lymphatic drainage follows a unidirectional flow, from deep subcutaneous and intramammary vessels, towards axillary and internal mammary lymph nodes. Although the majority of the blood supply comes from the internal mammary artery, only 4% lymph flows go to internal mammary nodes, with the majority (97 percent) of the lymph flows to the axillary nodes.

Presentation

Fat necrosis can be diagnosed clinically or radiographically in the majority of cases, without the need for biopsy. In surgical patients who have recently undergone a breast surgical procedure such as breast reduction, reconstruction, implant removal, or fat grafting after primary reconstruction, the most common presentation is the finding of a palpable mass or lump under the breast skin. There is a predilection for the subareolar and periareolar regions, but it can occur anywhere. Detection through imaging without an obvious source, such as recent surgery or trauma, or when associated with findings such as lymphadenopathy or skin change, requires exclusion of malignancy.