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 6
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Mass on left lower extremity
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T1
T1 post FS
T2 FS
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T1
T2 FS
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Diagnosis?
Periosteal ABC
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Periosteal ABC

• Exact cause is unknown, but recent theories
  include trauma, chromosomal aberrations, or
  alterations in local hemodynamics causing venous
  obstruction or AVF
• May arise de novo or within a pre-existing lesion
  such as a giant cell tumor, osteoblastoma,
  angioma, or chondroblastoma

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Periosteal ABC

• The fluid-fluid levels represent the
  sedimentation of RBCs and serum within cavities
  (the pt must remain motionless at least 10 min
  prior to imaging)

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Periosteal ABC

• Imaging Findings
• Multicystic, exophytic lesion with a thin shell
  of periosteal response
• Most commonly in diaphysis of long bones
• May be complicated by a pathologic fracture or
  compression of adjacent structures

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Periosteal ABC

• MRI
• Well defined exophytic lesion with a lobulated
  contour
• Cystic cavities with fluid-fluid levels and
  multiple internal septations
• Low signal rim surrounding the lesion

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Periosteal ABC

• DDx
• Simple bone cyst
• Chondromyxoid fibroma
• Giant cell tumor
• Osteoblastoma
• Telangiectatic osteosarcoma

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Periosteal ABC

• Treatment consists of surgical removal of the
  entire lesion and possible bone grafting to
  repair the defect
• Percutaneous injections of alcoholic solution of
  corn protein with thrombogenic and fibrogenic
  properties
• Recurrence is common