E1404. Pediatric Osteosarcoma: Pearls and Pitfalls
  1. Nelson Menendez; University of Central Florida College of Medicine
  2. Monica Epelman; Nemours Children's Hospital
  3. Lei Shao; Nemours Children's Hospital
  4. Dorothea Douglas; Nemours Children's Hospital
  5. Arthur Meyers; Cincinnati Children's Hospital Medical Center
Osteosarcoma is a malignant bone tumor most commonly presenting in children. It has a bimodal distribution with a peak incidence occurring during the ages of 10-14 years old and in adults greater than age 65. The first peak of osteosarcoma correlates with the increased proliferation of bone during the pubertal growth period. Osteosarcoma most frequently presents with localized bone pain, swelling, and an antalgic gait. The patient may attribute symptoms to trauma or strenuous exercise, causing the patient to be managed conservatively, but in these cases, the pain will persist and eventually result in further evaluation. The most common type of osteosarcoma is the conventional high-grade osteosarcoma. For conventional osteosarcoma, the diagnosis is typically made or strongly suggested based upon the initial radiographic appearance. Other types of osteosarcomas include low grade central, telangiectatic, small cell, and surface osteosarcomas. The purpose of this exhibit is to demonstrate the imaging findings seen in various types of osteosarcomas as well as imaging pearls and pitfalls unique to the different osteosarcoma subtypes and those occurring in unusual locations.

Educational Goals / Teaching Points
The goals of this review are to (1) review the imaging features of conventional high-grade osteosarcoma, (2) detail the imaging workup of conventional osteosarcoma, and (3) describe other less common subtypes of osteosarcoma with illustrative examples showing how they differ from conventional osteosarcomas.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Conventional radiographs remain the initial imaging modality typically performed for osteosarcoma and often establish or strongly suggest the diagnosis for conventional osteosarcomas. Other imaging modalities including magnetic resonance imaging (MRI), nuclear medicine scans, and computed tomography (CT) play key roles in further characterization and/or staging.

There are many subtypes of osteosarcoma with distinct histologic and radiologic findings. The imaging findings of the most common subtype, high-grade conventional osteosarcoma, are well recognized and the diagnosis is often strongly suggested on radiographs. Rarer types of osteosarcoma pose a greater challenge to radiologists as their appearance can overlap with benign etiologies. It is important for radiologists to be aware of these subtypes and the imaging features that differentiate them from other etiologies to prevent a delay in treatment.