Intramuscular Lipoma of Thigh: A Review of Literature
Lipomatous tumors are the most common among the mesenchymal tumors and constitute a large and complex group arising from adipose tissue. A majority of these are located in the subcutaneous tissue. They include the classic lipoma and its variants (fibrolipoma, angiolipoma, myolipoma, ossifying lipoma, chondrolipoma, spindle cell lipoma, and pleomorphic lipoma), lipoblastoma, hibernoma, and infiltrating lipoma including lipomatosis. Intramuscular lipomas (IMLs) constitute <2% of lipomas. They form an important group of deep-seated lipomas occurring deep to deep fascia. In the recent studies by various authors, better understanding of IMLs has led to identify different subtypes of these lipomas as well circumscribed, infiltrative, and mixed consisting of both infiltrative and well circumscribed. Various studies have described distinctive histopathological and imaging features to differentiate these lipomas from others such as atypical lipomatous tumors and hibernomas. This has helped to a large extent in the formulating treatment plan. IMLs can occur in any muscle but occur more commonly in thigh region of a middle-aged male. They frequently pose a challenge to the treating surgeon as they closely resemble atypical lipomatous tumor well-differentiated liposarcoma. Even with all the available modalities of investigations and histopathological examination, it may be difficult to accurately diagnose these preoperatively.