Search

Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) of bone is a rare childhood tumor most commonly located in the metadiaphysis. In skeletally immature patients, lesions of the epiphysis are rarely malignant, with the most common diagnosis being chondroblastoma. This article presents a case of ES/PNET of the proximal humeral epiphysis in a 12-year-old boy. To the authors' knowledge, this is the first reported case of epiphyseal ES/PNET confirmed with molecular testing. Radiographs of the patient's painful shoulder showed a well-defined lytic lesion within the humeral epiphysis. Magnetic resonance imaging suggested a chondroid tumor with surrounding edema. Based on the imaging characteristics, the patient's age, and the lesion's location, a preliminary diagnosis of chondroblastoma was made. A trochar biopsy of the lesion demonstrated a small, round, blue cell tumor on frozen section. Subsequently, immunohistochemical staining was uniformly positive in a membrane pattern for CD99, and molecular diagnostic testing demonstrated a EWSR1/FLI1 fusion transcript, confirming the pathologic diagnosis of ES/PNET. Although metadiaphyseal locations for ES/PNET are most common, this case adds to previously reported cases of epiphyseal ES/PNET, suggesting that the diagnosis be considered for pediatric epiphyseal tumors. This case also demonstrates why following rigorous oncologic treatment algorithms by obtaining a limited trochar biopsy, even in the case of a confident radiographic diagnosis, is critically important; the biopsy results can lead to a major change in treatment and avoid contamination of a larger area of soft tissue and bone., (Copyright 2013, SLACK Incorporated.)

Epithelioid hemangioma is a rare tumor that can have bone involvement. Its clinically and radiographically aggressive appearance mimics a malignant neoplasm. Although epitheliod hemangioma has been described as having an aggressive appearance on magnetic resonance imaging (MRI) and plain radiographs, this is the first reported case of pathologic fracture associated with this lesion to our knowledge. This article describes a case of epithelioid hemangioma involving the distal humerus, which initially presented with progressive pain and fracture of the lateral condyle. The aggressive appearance on plain radiographs and MRI suggested a malignant bone tumor. This preliminary diagnosis was confirmed due to the presence of local lymph node spread on positron emission tomography/computed tomography. After a core needle biopsy revealed nondiagnostic tissue, rather than performing a wide resection based on a presumptive malignant diagnosis, we followed the standard diagnostic algorithm and performed an open biopsy with temporary internal stabilization. The tissue sample was adequate and revealed a diagnosis of epithelioid hemangioma. Based on this finding, we were able to proceed with surgical management, including curettage of the lesion, placement of a bone graft, and internal fixation, rather than a wide resection with elbow joint replacement. This article emphasizes the need for careful adherence to the diagnostic algorithm for musculoskeletal tumors. In doing so, a definitive diagnosis was reached, and our patient was able to resume his occupation as a laborer without the restrictions that would have accompanied elbow arthroplasty., (Copyright 2012, SLACK Incorporated.)