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Abstract
Ewing's sarcoma is one of the most common primary bone tumors of childhood. The tumor is almost always metaphyseal or diaphyseal, within long bones. In children, lesions of the epiphysis are often benign, with the most common diagnosis being chondroblastoma. Rarely, 1 %-2% of Ewing sarcomas may involve epiphysis. We present a case of Ewing's sarcoma of the proximal humeral epiphysis in a 13- yearold boy. This case adds to previously reported cases of epiphyseal Ewing sarcoma and suggests that the diagnosis should be considered for pediatric epiphyseal lesions.
Keywords: Epiphysis, Ewing's sarcoma, primary malignant bone tumor
Introduction
E piphyseal bone lesions are often benign in skeletally immature patients. A study on a large series of 2758 tumor cases 1996 confinned chondroblastoma as the most frequent epiphyseal bone tumor, especially in the second decade of life. There were no cases of primary malignant bone tumor of the epiphysis in that study.1
Ewing sarcoma is the second most common primary bone tumor of childhood after osteosarcoma, and typically occurs in children and adolescents between 10 and 20 years of age, and has a slight male predilection.2-3
Ewing's sarcoma is a small-blue-round-cell tumor and closely related to the soft tissue tumors pPNET, Askin tumor and neuroepithelioma, which collectively are referred to as Ewing's sarcoma family of tumors (ESFT).2
Ewing's sarcoma is more commonly seen in the appendicular skeleton and typically involves the femur, tibia, humerus, or fibula. As for location within long bones, the tumor is almost always metaphyseal or diaphyseal (mid-diaphysis: 33%, metadiaphysis: 44%, metaphysis: 15%). Rarely, 1%-2% of Ewing sarcomas may involve epiphysis.3-4 This article presents a case of primary Ewing's sarcoma of the proximal humeral epiphysis in...