E1017. Osteochondroma: A Radiographic Review of the Diagnosis and its Complications
  1. MeNore Lake; Mount Auburn Hospital
  2. Edward Marianacci; Mount Auburn Hospital
Osteochondromas represent the most common benign primary bone tumors in the adult and pediatric population. This prevalence makes understanding the pathophysiology of osteochondromas and their distinguishing characteristics across multiple imaging modalities critical to appropriate management. Although most osteochondromas are found in asymptomatic patients, these lesions may produce symptoms in a variety of ways secondary to complications, varying from benign causes to malignant degeneration. This educational exhibit explores the underlying pathophysiology and multimodality assessment of osteochondromas and Multiple Hereditary Exostosis. This exhibit also establishes a systematic approach to identify the wide range of osteochondroma complications through a case-based review including pediatric and adult patients.

Educational Goals / Teaching Points
Educational Goals: 1) Describe the pathophysiology and presentation of osteochondromas, the most common benign primary bone tumor, including Multiple Hereditary Exostosis. 2)Distinguish hallmark imaging features on multiple modalities -Plain Film, CT, MRI. 3)Apply a systematic approach to identify osteochondroma complications.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Key Imaging Findings on Plain Film, CT: -Lesion morphology: sessile or pedunculated - Continuity with the central medullary cavity -Cartilage component characteristics including thickness and matrix characteristics Key Imaging Findings on MRI: -Lesion morphology: sessile or pedunculated -Homogeneous T1 marrow signal with continuity with the central medullary cavity -T2 hyperintense signal as an indicator of associated bony or soft tissue edema -Cartilage component characteristics including thickness, matrix characteristics, and enhancement features Key Imaging Findings in Complications of osteochondromas: Extrinsic Complications: -Mass effect on adjacent muscle, bone, or neurovascular tissues -Mechanical changes of adjacent bone -Joint malalignment and limb length discrepancy -Reactive myositis -Bursal formation Intrinsic Complications: -Fracture -Malignant transformation

Osteochondromas are the most common primary bone tumor and present with a spectrum of appearances across multiple imaging modalities. An awareness of its complications, which include symptoms due to benign etiologies and signs suspicious for malignant transformation, is important for the radiologist in performing an accurate assessment.