Working Diagnosis:
Ewing Sarcoma

Treatment:
The patient was referred to orthopedic oncology for further management. He subsequently underwent surgical resection of the distal fibular diaphysis. His post-operative x-rays show the remainder of his fibula Case Photo #4 . He then underwent several months of chemotherapy.

Outcome:
Following surgery and chemotherapy, the patient developed a foot drop and deficits in sensation of his left foot. Weight-bearing activities, recreational sports, and ambulation were limited due to pain. He used an ankle brace for support. He was referred to physical therapy for functional rehabilitation.

The patient returned a year later with a return of left ankle pain. He developed severe back pain one month later and continued to follow up with his oncologist. He underwent further MRI and PET scans showing metastatic lesions in his thoracic spine. Unfortunately, he had a progressive downhill course and died from metastatic disease.

Author's Comments:
Ewing Sarcoma is a rare bone malignancy that occurs in the diaphysis of long bones such as the femur, tibia, and humerus. Incidence is reported to be 3 per 1,000,000. It is primarily found in young adults under the age of 25 and is the second most common primary malignant bone tumor in children. The most common presenting symptom is pain. It may be caused by a de novo genetic translocation of t(11;22), which creates an oncogenic fusion protein. Biopsy is required for diagnosis, and metastasis frequently occurs to lungs, bone, and bone marrow. It is typically responsive to chemotherapy. Ewing Sarcoma in a patient in their fifties is extremely rare, but this case did fit the typical presentation with a prolonged course of symptoms before diagnosis. This case also highlights the importance of careful review of x-rays, as the subtle cortical irregularity of the fibula prompted advanced imaging and ultimately led to diagnosis(References 1-3).

Editor's Comments:
While pain is the most common primary presenting symptom, up to one-third of patients with Ewing sarcoma or other osteosarcoma also present with a palpable mass, demonstrating the importance of a thorough and careful physical exam in these cases(4).

Studies show that both CT and MRI imaging are effective in local staging of Ewing sarcoma, however MRI is frequently preferred given the superior visualization of surrounding soft-tissue structures and for delineation of the local extent of the tumor(5). On MRI, Ewing sarcoma will have a low signal intensity on T1-weighted images and high signal intensity on T2 weighted images which will highlight the edema frequently associated with the tumor. Additionally, gadolinium enhancement is noted with Ewing sarcoma(6).

Treatment recommendations for adult patients with Ewing sarcoma are based on pediatric protocols and the optimal approach for a particular patient depends on a multitude of factors. Typically, patients are treated with neoadjuvant chemotherapy followed by surgery in an effort to gain control over localized disease(6).

References:
1 Ginsberg JP, Woo SY, Hicks MJ, Horowitz ME. Ewing's sarcoma family of tumors: Ewing's sarcoma of bone and soft tissue and the peripheral primitive neuroectodermal tumors. In: Principles and Practice of Pediatric Oncology, 4th, 2 Pizzo PA, Poplack DG (Eds), Lippincott, Williams and Wilkins, Philadelphia 2002.
3 Widhe B, Widhe T. Initial symptoms and clinical features in osteosarcoma and Ewing sarcoma. J Bone Joint Surg Am. 2000 May;82(5):667-74. doi: 10.2106/00004623-200005000-00007. PMID: 10819277.
4 Verrill MW, Judson IR, Harmer CL, Fisher C, Thomas JM, Wiltshaw E. Ewing's sarcoma and primitive neuroectodermal tumor in adults: are they different from Ewing's sarcoma and primitive neuroectodermal tumor in children? J Clin Oncol. 1997 Jul;15(7):2611-21. doi: 10.1200/JCO.1997.15.7.2611. PMID: 9215832.
5 Widhe B, Widhe T. Initial symptoms and clinical features in osteosarcoma and Ewing sarcoma. J Bone Joint Surg Am. 2000 May;82(5):667-74. doi: 10.2106/00004623-200005000-00007. PMID: 10819277.
6 Panicek DM, Gatsonis C, Rosenthal DI, Seeger LL, Huvos AG, Moore SG, Caudry DJ, Palmer WE, McNeil BJ. CT and MR imaging in the local staging of primary malignant musculoskeletal neoplasms: Report of the Radiology Diagnostic Oncology Group. Radiology. 1997 Jan;202(1):237-46. doi: 10.1148/radiology.202.1.8988217. PMID: 8988217.
7 Zollner SK, Amatruda JF, Bauer S, Collaud S, de Alava E, DuBois SG, Hardes J, Hartmann W, Kovar H, Metzler M, et al. Ewing Sarcoma-Diagnosis, Treatment, Clinical Challenges and Future Perspectives. Journal of Clinical Medicine. 2021; 10(8):1685. https://doi.org/10.3390/jcm10081685

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