Low-grade fibromyxoid sarcoma of the abdominal wall in an 8-year-old boy

Low-grade fibromyxoid sarcoma (LGFMS) is an extremely rare neoplasm classified as a fibroblastic soft tissue tumor. It has been described by its characteristic deceptively benign histological appearance with metastatic potential during long-term follow-up. We herein describe an 8-year-old boy with LGFMS located in the internal oblique muscle. Histological findings of the resected specimen included contrasting fibrous and myxoid areas with a swirling, whorled growth pattern; bland, benign-appearing fibroblastic spindle cells; and large collagen rosettes. Immunohistologic examination revealed mucin 4 positivity. The surgical margin of the tumor was obscure; therefore, we performed an additional resection 2 months later with a 1 cm margin from the edge of the tumor. No recurrence or metastasis was identified throughout 1 year of follow-up.