Intraneural Ewing Sarcoma of Fibular Nerve: Case Report, Radiologic Findings and Review of Literature

Intraneural Ewing sarcoma (ES) was first described in 1918 by Stout in a tumor of the ulnar nerve. These tumors are in the category of ES family of tumors, together with ES of bone, extraosseous ES, and primitive neuroectodermal tumor. ES typically occurs in the second decade of life; only 20% of cases affect elder people. The most frequently involved sites are the craniospinal vault and cauda equina, while the peripheral nerve location is extremely rare (only 11 cases mentioned in the literature to date). CASE DESCRIPTION: This case report documents a rare case of a 46-year-old woman with an intraneural extraosseous ES and offers a complete radiologic documentation including contrast magnetic resonance imaging and microbubble contrast-enhanced ultrasonographic data. A review of the literature about diagnostic and treatment management is presented. CONCLUSIONS: The challenge of intraneural extraosseous ES consists of the right balance between the necessity to consider a potential malignant nature of the lesion and perform adequate surgical excision in a relatively brief time from the first clinical examination and the fact that these are extremely rare pathologic entities among most frequent cases of completely benign tumors, which could even have the same clinical and radiologic presentation. For this reason, a multidisciplinary setting with a team of neurosurgeons, orthopedic specialists, radiologists, pathologists, and oncologists should manage these cases as soon as a pathologic diagnosis is available. More attention should be focused on other therapies that effectively manage microscopic pathologic involvement, without increasing the risk of postoperative morbidity.