Intramuscular Lipoma of the Thenar: A Rare Case.

Lipomas are the most common benign mesenchymal tumors. They are located either subcutaneously or under the investing fascia in intramuscular or intermuscular regions. The reported frequency of intramuscular lipomas among all benign adipocytic tumors is 1.0%-5.0% and for intermuscular lipomas is 0.3%-1.9%. The frequency of these lesions is the same in all age groups, but in adults deep seated-lipomas are most commonly discovered between the ages of 30 and 60. The most common sites of involvement of intramuscular lipomas are the large muscles of the extremities, especially those of the thigh, shoulder, and upper arm. Intramuscular lipomas of the hand are extremely rare and only few cases have been reported in the literature. In cases with hand location, they may present with functional deficit or neurovascular compromise due to the effect of the mass. We report an unusual case of a large intramuscular lipoma of the thenar that was treated with surgical excision due to the impairment of hand function.