What is your diagnosis?

Ewing sarcoma, which in this case is presenting with periosteal reaction and cortical bone destruction. X-ray findings include sunburst reaction (blue in Image 2) and Codman triangle (arrow)

• Pearl: Presentation of Ewing sarcoma is highly variable but will usually have a permeative, or “moth-eaten,” appearance and a lamellated, or “onion-skin,” periosteal reaction (Image 3). They most commonly occur in the lower limbs with the femur being the most common, followed by the pelvis and upper limbs. Most cases present in children between the age of 10 and 20 years old.

Image 2. Case with annotations courtesy of Dr S Benoudina, Radiopaedia.org,  rID: 84751

Image 3. Case courtesy of Dr MA Munir, Radiopaedia.org,  rID: 80151

What other etiologies can cause this finding? How can you rule it out?

Osteosarcomas and acute osteomyelitis and can also present with periosteal reactions and as a permeative process on plain films. The definite diagnosis of Ewing sarcoma is made via a combination of clinical history, morphological features on plain films and MRI, as well as biopsy. [3] 

• Pearl: Although they can be seen in either, lamellated (onion skin) periosteal reactions are more frequently seen with Ewing sarcoma, while sunburst periosteal reaction (Image 4) or presence of a Codman triangle (Image 5) are more common in osteosarcoma. 

Image 4. Case courtesy of H Hamidi, Radiopaedia.org, rID: 80616

Image 5. Case with annotations courtesy of Assoc Prof Frank Gaillard, Radiopaedia.org, rID: 7527

What are patients with this finding predisposed to?

Patients with Ewing sarcoma are susceptible to metastases, pathological fractures, secondary malignancies, local recurrence, and radiation-associated and chemotherapy associated morbidities. [2]

What is your disposition and management?

Urgent referral to orthopedic and pediatric oncology for evaluation for chemotherapy and/or local therapeutic options such as radiation therapy or surgical resection. [2]

• Pearl: The 5 year survival rate is 50-75% for a patient with localized disease only at time of initial presentation. [3]