Musculoskeletal MRI Unknown Cases Texas Radiologic Society 93rd Annual Scientific Meeting Austin, TX

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Musculoskeletal MRI Unknown CasesTexas
Radiologic Society93rd Annual Scientific
MeetingAustin, TXApril 21-23, 2006

• Lezlie R Warren, MD CPT USAF
• Justin Q Ly, MD CPT USAF
• Douglas P Beall, MD
• Wilford Hall Medical Center
• San Antonio, TX

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Case 3
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20 y/o male referred from outside hospital
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T1
GRE
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T2 FS
Cartilage Cap
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Diagnosis?
Osteochondroma
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Osteochondroma

• Most common benign bone lesion accounting for
  20-50 of all bone tumors
• If multiple, associated with Multiple Hereditary
  Exostoses
• Results from the separation of a fragment of
  epiphyseal growth plate cartilage which
  subsequently herniates through the periosteal
  bone surrounding the growth plate

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Osteochondroma

• Complications
• Deformity (cosmetic or osseous)
• Fracture (host bone or lesion)
• Vascular or neurologic compromise
• Bursae formation (bursa exostotica)
• Malignant Transformation to chondrosarcoma (1)

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Osteochondroma

• Features suggestive of malignant transformation
• Pain (in the absence of fracture or bursitis)
• Growth of lesion beyond age of skeletal maturity
  (own growth plate)
• Thick cartilage cap gt 1.5 cm (is normally 1-3 mm,
  rarely gt 1 cm)

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Osteochondroma

• Imaging Findings
• Pedunculated with slender pedicle, usually
  directed away from adjacent growth plate
• Or sessile, with a broad base attached to the
  cortex
• There is communication of the cortex and the
  medullary portion of the lesion and host bone
• Calcifications in the chondro-osseous portion of
  the stalk (sign of benignity)
• Cartilaginous cap (high signal on GRE and T2
  images)

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Osteochondroma

• DDx
• Osteoma
• Periosteal chondroma
• Juxtacortical osteosarcoma
• Soft tissue osteosarcoma
• Juxtacortical myositis ossificans
• Treatment
• Solitary osteochondromas can be monitored in the
  absence of clinical symptoms or complications
• If malignant transformation is suspected, the
  lesion is surgically resected