Intramuscular lipoma of the subscapularis muscle

CONTEXT: Intramuscular lipomas are benign tumors that infiltrate the muscles. CASE REPORT: We describe the case of a 58-year-old female patient with an axillary lump. The lump was a lipoma inside the subscapularis muscle. It is important to differentiate these lesions from liposarcomas and from other diseases that may present as axillary lumps. The most accurate imaging method for differentiating benign lipomatous tumors from liposarcomas is magnetic resonance imaging, but surgical removal of these intramuscular lesions to confirm the diagnosis is recommended. CONCLUSION: Intramuscular lipomas are a rare cause of benign axillary lumps and should be considered in making differential diagnoses on axillary masses.