Bone
Non-neoplastic or metabolic disease
Infarct

Author: Nat Pernick, M.D. (see Authors page)

Revised: 3 October 2016, last major update August 2013

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: Bone Infarct[title]
Cite this page: Infarct. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/boneinfarct.html. Accessed December 7th, 2016.
Definition / General
  • Diaphysometaphyseal infarction: due to infection, vasculitis, sickle cell disease, pheochromocytoma, other vascular disease, Gaucher’s disease, pancreatitis, idiopathic, decompression sickness (historically)
  • Epiphysometaphyseal infarction: same as above, also fractures and dislocations, corticosteroids for collagen vascular diseases, thromboembolic disease, systemic lupus erythematosus, rheumatoid arthritis, Langerhans cell histiocytosis, osteochondrosis
  • Medullary infarcts: patchy necrosis involving cancellous bone and marrow; cortex has collateral blood flow
  • Subchondral infarcts: wedge shaped; cartilage remains viable since nutrients are present in synovial fluid
  • Sites: femoral head or other convex articular surfaces (see aseptic bone necrosis)
  • Complications: large infarcts are rarely associated with osteosarcoma, fibrosarcoma, malignant fibrous histiocytoma; usually adult males in femur / tibia; poor prognosis (Arch Pathol Lab Med 1996;120:482)
  • Note: osteocytes may be lost even in normal bone due to decalcification
Radiology Description
  • No changes until third week
  • Then reduced density in areas of dead bone and increased density due to new bone formation
  • Changes appear irregular / mottled
  • Thick, serpentine border
Case Reports
Gross Description
  • Early (identifiable at autopsy): elongated pale area with hyperemic border sharply demarcated from adjacent bones, radiologically normal
Micro Description
  • Early: ghost marrow cells with pyknotic basophilic nucleated red blood cells; irregular cystic spaces due to fat necrosis, focal calcification, dead trabeculae
  • Late: ingrowth of granulation tissue at periphery of lesion, “creeping substitution” of dead bone by layering of new bone on trabecular surfaces at periphery, rim of collagen forms around periphery, often with calcification
Differential Diagnosis
  • Enchondroma: radiologically resembles infarct but lacks its sharp border, has diffuse calcification