Solitary infantile myofibromatosis in the upper extremities: Case report.

Infantile myofibromatosis (IM) is a mesenchymal tumor that may present in infants in a couple of major forms: solitary (myofibroma) and multicentric (myofibromatosis) which can be more subdivided into IM without or with visceral involvement. The tumors present as nodular lesions in the soft tissues, bones, and/or internal organs. Although the success of imaging in suggesting the correct diagnosis can't be denied, histopathology and Immunohistochemical examinations are necessary to confirm the diagnosis of IM as it might be misdiagnosed as a malignant tumor. We report a case of solitary infantile myofibromatosis in the upper extremities discovered in a 9-year-old girl. She had swelling and an enlargement on the posterior forearm on the ulnar side. The X-ray showed a lytic lesion with swollen soft tissue. The patient underwent an MRI which suggested the diagnosis of myofibroma. Then, solitary myofibroma was confirmed histologically. Infancy's most prevalent fibrous tumor is IM. Its prognosis depends on the visceral involvement. Imaging, especially MRI is the ideal tool to diagnose it.