Management of adipose tumors in the limbs

Adipose tumors of the limbs are the most common soft tissue lesions and are essentially benign (lipomas). However, in some cases, they can be considered as tumors with intermediate malignancy (atypical lipomatous tumor [ALT]) or sarcoma lineage (liposarcoma [LS]). The essential work-up for a potential adipose tumor consists of a clinical examination and initial ultrasound imaging to determine the size (more or less than 5 cm), the location (over or under the fascia) and any potential atypical vascularization. As needed, MRI will complete the assessment and validate the ultrasound results and confirm the fatty nature of the lesion. Percutaneous biopsy will be done when a deep fatty lesion is larger than 5 cm (long axis), with detection by amplification of the MDM2 gene that guides the diagnosis towards ALT or dedifferentiated LS. Superficial lesions without atypia are not challenging from a surgical point of view. However, large ALT can be more difficult to manage. Their local malignancy does not justify sacrificing any critical structures. As for true LS, their treatment is well defined, with tumor excision addressed at a center belonging to the Network of Sarcomas Reference Centers in France (NETSARC+) and for potential (neo)adjuvant treatment if needed. Inappropriate treatment of a malignant tumor can have serious consequences (loss of chance to survive or to be cured) for the patient. Furthermore, treatment at a specialized cancer center has been proven to be effective as it improves overall survival and reduces local recurrences.