Low-grade fibromyxoid sarcoma, a deceptively benign tumor in a 5-year-old child.

Low-grade fibromyxoid sarcoma (LGFMS) is very uncommon in the pediatric population with only 20% of reported cases under the age of 18. The youngest reported case to date has been in a 4-year-old child. Lesions are usually slow growing and asymptomatic, and locations described in children have included paravertebral, thigh and intrathoracic. Although benign in appearance, these lesions can behave aggressively, with local recurrence and distant metastases primarily to lungs. These lesions can be resistant to the usual chemotherapy and radiotherapy with surgical resection being the treatment of choice. We report a case of a 5-year-old boy who presented with a mass in the left buttock.