Infantile Fibrosarcoma Presenting as Neck Mass: A Case Report

A one year old boy presented with a mass in the posterior triangle of left side of neck for ten months with rapid increase in size since one month. Radio-imaging was done. He underwent surgery, the mass was excised and the histopathological examination was done. Clinically, it was thought to be as schwannoma. Tumor measured 10 x 8 x 6 cm approximately, fixed with underlying tissue, venous prominence seen on bosselated surface and was non-tender. Microscopically, showed a cellular neoplasm composed of spindle cells arranged in herringbone pattern, also as fascicles and bundles, with focal area showing slit like thin-walled vessels simulating hemangiopericytoma like vasculature. Focally, shows infiltration of muscle and fat. Immunohistochemistry study was performed. Correlating histology with clinical, radiology and immunohistochemistry findings, the patient was diagnosed as a case of Infantile Fibrosarcoma of neck region, a relatively rare malignant fibroblastic tumor, occurring mostly in infancy, often misdiagnosed with benign tumor.