Abstract
Lipoma is one of the most frequently seen benign soft tissue tumors. It has been reported to localize mostly in the muscles of the femur and trunk. Lipomas are frequently seen in the subcutaneous tissues. They might be originating from the periphery of a muscle or directly from inside a muscle and are seen as intramuscular or intermuscular. Intramuscular lipomas of the hand are extremely rare. Literature search, we identified 15 cases in 12 articles reported. It is manifested as a painful or painless mass lesion and neurological signs according to its localization. Rapidly growing, deeply located and lipomas larger than 5 cm have a potential for malignancy. It is diagnosed with ultrasonography (USG) and magnetic resonance imaging (MRI). The best imaging method for lipomas is MRI. MRI sometimes may not be enough to understand their relationship with the nerve. Therefore, we recommend that electromyography (EMG) be performed. EMG gives us an idea of nerve involvement in cases with suspicious neurological findings. In case of nerve involvement, marginal excision procedure should be done more carefully. When literature review and our case is evaluated; the 4 cm size can be thought of as "giant" according to the anatomical position at hand. For the hand, however, this requires more case reports and a new definition of "giant lipoma".

Key words: Thenar, intramuscular, lipoma, electromyography, giant, rapidly