Bone Island


Key Radiographic Findings
1-Cortical destruction, 2-Periostitis, 3-Zone of transition

  • Benign:
    1-No cortical destruction
    2-Benign periostitis: thick wavy, uniform or dense = low-grade chronic irritation
    3-Narrow zone of transition; can be traced with a pencil
  • Malignant:
    1-Cortical destruction
    2-Aggressive periostitis: lamellated (onion-skinned), amorphous, sunburst
    3- Wide zone of transition; imperceptible
  • Permeative lesions (multiple small holes): not easily categorized as benign vs malignant: multiple myeloma, primary lymphoma of bone, Ewing's sarcoma

Benign Skeletal neoplasm fracture risks
-plain radiograph criteria: increased risk of fracture if the defect length is >3.3 cm, the defect width is >2.5 cm or there is more than 50% of the cortex involved as measured on A/P or lateral x-rays.
-CT-based rigidity analysis is more specific (97% specific vs 12% for xray). (Leong NL, JBJS 2010;92:1827)

Metastatic Bone Disease

  • "viscious cycle" of lytic bone metastases from TGFb-mediated release of PTHrP  stimulating osteoclastic resorption of bone and releasing more TGFb.  Consider antiresorptive therapy with zoledronic acid or denosumab.
  • Bickels J, JBJS 2009;91A:1503
  • Biermann S, JBJS 2009;91A:1518


  • Mazabraud Syndrome: fibrous dysplasia and intramuscular myxomas. Rarely can develop osteosarcoma. (Crawford EA, JBJS 2009;91A:955
  • Klippel-Trenaunay Syndrome: rare congenital disorder characterized by the triad of cutaneous capillary malformation, varicose veins, and hypertrophy of bone and soft tissue (Kihiczak GG, Int J Dermatol 2006;45:883).
  • Morquio Disease (MPS IV): autosommal-recessive defect in the activity of one of two enzymes, N-acetylgalactosamine-6-sulfate (MPS-IVA_ or beta-galactosidase (MPS IVB); results in the accumulation of keratan sulfate and chondroitin-6 sulfate (Montano AM, J Inherit Metab Dis 2007;30:165).
  • Fibrodysplasia Ossificans Progressiva: rare; disabling autosomal dominant disorder of joint malformation and progressive heterotopic ossification caused by a recurrent missense point mutation in activin receptor IA (ACVRI / ALK2 / a BMP type I receptor). (Moore R, JBJS 2009;91A:1497).
  • McCune-Albright syndrome:  polyostotic fibrous dyplasia and endocrine disturbances, especially precocious puberty.   Hyperpigmentantion with jagged border("Coast of Maine" border).


  • MRI:homogenous with density of subcutaneous fat on all sequences.No enhancement
  • Treatment  =marginal excision.

Aneurysmal bone cysts

  • frequently occur in the first two to three decades of life
  • pain and a slow-growing lesion.
  • Xray= expansile lesion with septae or striations.
  • Treatment = curettage and grafting of the lesion.


  • xray = typically shows lucency of bone, periosteal reaction, and a permeative pattern

Giant cell tumor of the tendon sheath

  • often arises from the synovial lining of tendon sheaths
  • frequently found in the hand and foot.  Slow growing but can invade adjacent structures. 
  • Treatment = excision

Giant cell tumor

  • epiphysis of long bone
  • xray = radiolucent lesion with a small rim of reactive bone.
Neurilemoma (Schwannoma)
  • benign tumor of nerve sheath (Schwann cell) origin
  • solitary, well-encapsulated lesion located on the surface of a peripheral nerve.
  • Treatment = excision without damaging the underlying nerve
  • spindle cell tumor arising within a peripheral nerve.  Invasive
  • Due to its location, it can interfere with distal nerve function
  • solitary or multiple 
  • von Recklinghausen's disease.
  • Treatment = resection which requires removal of the affected nerve with resultant distal nerve dysfunction
  • Benign tumor of hyaline cartilage
  • most frequently occurs in an intramedullary metaphyseal location. 
  • Radiologic characteristics: cartilage mineralization pattern (rings, arcs and stippled calcifications); minimal to no endosteal scalloping. 
  • Follow clinically and radiologically to ensure there is interval change.
  • Douis H, Saifuddin A. The imaging of cartilaginous bone tumours. I. Benign lesions. Skeletal Radiol. 2012 Sep;41(10):1195-212. 
  • Weber KL, O'Conner MI: Benign cartilage tumors. In: Schwartz HS, ed. Orthopaedic Knowledge Update: Musculoskeletal Tumors 2. Rosemont, IL: AAOS; 2007:103-120.
  • Radiologic features: endosteal scalloping, periosteal reaction, cortical destruction, and soft-tissue extension. 
Dedifferentiated chondrosarcoma
  • Imaging:  areas of stippled, chondroid-type calcification and cortical destruction.
  • MRI:  extraosseous extension that is not seen in a typical low-grade chondrosarcoma. 
  • Hstology: areas of low and high-grade lobular chondroid material with no osteoid matrix.
Soft-tissue mass
  • Subfascial masses which enhance on contrast MRI should be biopsied for definitive diagnosis.  Soft-tissue sarcomas can be painless with minimal symptoms.
Fibrous Dyplasia
  • "ground glass" appearance
  • Parekh SG, Donthineni-Rao R, Ricchetti E, Lackman RD. Fibrous dysplasia. J Am Acad Orthop Surg. 2004 Sep-Oct;12(5):305-13 

Desmoid tumor:  Desmoid fibromatosis can be associated with adenomatous polyposis coli; consider colonoscopy to screen for colon polyps.