Intramuscular myxoma is a distinct benign tumor confined to muscles. This tumor usually favors the thigh and shoulder. We are reporting a case of intramuscular myxoma of the forearm in an elderly female, a very rare site for this tumor. The magnetic resonance features of intramuscular myxoma are described. The differential diagnosis that included acute hematoma, acute abscess, intramuscular synovial cyst, schwannoma and malignant soft tissue tumors with myxomatous degeneration is discussed. The association between intramuscular myxomas and fibrous dysplasia has been emphasized.