A sporadic case of myositis ossificans of the forearm presenting clinically as mesenchimal tumor

摘要

Saxc5xbeetakAim: Myositis ossificans is a benign, solitary, self-limiting lesion characterized by extraskeletal formation of focal heterotopic bone and cartilage in soft-tissue. It generally affects the muscles, ligaments, and fascia. Myositis ossificans usually occurs in young adults mostly after localized trauma, with predilection in the anterior muscle groups of the thighs and arms. The aim of this case report was to present a rare case of myositis ossificans in the forearm, which presented as a bump on the forearm and weakness of the hand. The clinical signs and imaging appearance can be easily confused with malignant lesions, as was the case in our patient. Case report: A 48-year old woman was presented with a palpable formation in the distal and volar part of the right forearm. She had suffered from weakness of the forearm for a while, and had no history of acute injury or trauma of the forearm. Preoperative magnetic resonance imaging demonstrated malignant fibrous histiocytoma-like tumor, but final pathohistological examination revealed rare disease, myositis ossificans. Postoperatively, the patient had some minor neurological deficits, such as paresthesia, and less flexible fingers. After six months, the patient showed a major improvement in physical therapy, and the MRI findings were unremarkable. Conclusion: Myositis ossificans should be considered as a possible diagnosis for a soft-tissue mass in the forearm shown on the imaging findings. Due to the rare location of the lesion, the postoperative histopathological examination is necessary for making an ultimate diagnosis.