What is lipoma?

Updated: Oct 07, 2019
  • Author: Guy J Petruzzelli, MD, PhD, MBA, FACS; Chief Editor: Gregory Gary Caputy, MD, PhD, FICS  more...
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Answer

Answer

The most common tumor of adipose origin is the lipoma. Lipomas appear as painless, round, mobile masses that are well-circumscribed and often pseudo-encapsulated. [99] These benign lesions are often located in the subcutaneous tissues of the head, neck, shoulders, and back. The average age at presentation is between the fourth and sixth decades of life. Histologic examination reveals mature adipose tissue, often encapsulated by fibrous layers. Focal points of necrosis or calcification can also be seen.

Most lipomas can be managed conservatively. If the lipoma becomes painful or begins to grow rapidly, then surgical excision is definitive treatment. Infiltration of lipomas into muscle has been described. The removal of such infiltration leads to bleeding and postoperative hematomas. Therefore, larger and deeper lipomas should be removed under controlled conditions by a skilled surgeon to ensure proper dissection. 

Variants of lipomas include angiolipomas, spindle cell lipomas, and pleomorphic lipomas. All lipomas must be distinguished from liposarcomas. Therefore, tissue should be sent for histopathologic examination. Angiolipomas tend to be more painful than lipomas. They also tend to occur more often in younger individuals. Consisting of painful, well-circumscribed, subcutaneous nodules with a marked capillary component, these lesions usually affect the upper extremities and trunk.

Spindle cell lipomas [100] and pleomorphic lipomas [101] are two variants of lipomas that are easily confused with liposarcomas upon histologic examination. Both of these benign tumors have well-demarcated margins and usually occur on the back or on the posterior surface of the neck and shoulders. Histologically, these lesions contain mature lipocytes within a mucinous background. In spindle cell lipomas, the lesion also contains fibroblast-like spindle cells that are associated with bundles of collagen. In contrast, pleomorphic lipomas contain multi-nucleated giant cells associated with the bundles of collagen.


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