Difference between revisions of "Bone"

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*Pancytopenias - due to oblieration of the marrow space.
*Pancytopenias - due to oblieration of the marrow space.
*[[bone fractures|Fractures]].
*[[bone fractures|Fractures]].
*Radiologic diagnosis.


===Gross===
===Gross===

Revision as of 21:24, 11 April 2012

Bone is a scaffold it bears weight and occasionally gets infected.

Tumours often spread to bone and occasionally arise in bone. Bone tumours are dealt with in the bone tumours article.

Normal bone

Bone

Anatomy

  • Epiphysis = rounded end of the bone.
  • Metaphysis = between epiphysis and diaphysis; contains epiphyseal plate - site of growth in childhood.
  • Diaphysis = shaft, mid-portion, contains bone marrow.

Image:

Matrix

Two types (based on arrangement of collagen):

  1. Woven.
    • Always abnormal in adults.
    • Collagen arranged haphazardly - mechanically weak.
  2. Lamellar.
    • Collagen organized in layers (lamellae).

Woven vs. lamellar:

  • Easiest way to differentiate: polarize; lamellar bone has well-defined layers.

Images:

Cells

  • Osteocytes.
    • Sit in lacunae.
      • Empty lacunae = necrotic bone.
  • Osteoblasts.
    • Make bone.
  • Osteoclasts.
    • Destroy bone.
    • Multinucleated.

Memory device: 'b' before 'c'.

Bone marrow

Main article: Haematopoiesis
  • One should see three cell lines:[4]
    1. Erythroid (red cells).
    2. Myeloid (white blood cells).
    3. Megakaryocytic (platelets).

Note: Lymphocytes are considered separately and typically spared in bone marrow failure.[5]

Identifying the lines:[6]

  1. Megakaryocytes:
    • Big cells ~ 3x the size of a RBC.
  2. Normoblasts (RBC precursors):
    • Hyperchromatic, i.e. blue, nucleus.
  3. Myeloid line:
    • Granules.
    • Reniform nucleus, i.e. kidney bean shaped nucleus.

Images:

Organization

  • Mature hematopoeitic cells at the centre (distant from bone).
  • Immature hematopoeitic cells adjacent to the bone.

Note:

Benign variants

Hyperostosis frontalis interna

  • Extra-thick frontal bone.[8]
  • No clinical significance -- just has to be recognized as a "nothing".

Infections

Osteomyelitis

General

  • Hematogenous - often in children.
  • Direct entry (skin defect) - adults with diabetes.

Microscopic

Chronic osteomyelitis

Microscopic

Features:

  • Plasma cells.
    • May be sterile, i.e. no organisms.
  • +/-Amyloid.
    • ~10% of patients in one series.[9]

Bone tumours

Main article: Bone tumours

This is a big topic. It is dealt with in a separate article.

The bone tumour article covers tumour mimics, e.g. brown cell tumour.

Fractures

Main article: Bone fractures

This is dealt with in the forensic pathology article.

Others

The following is a collection of stuff that doesn't really fit in another category or is just weird.

A general DDx for cystic bone lesions is found on radipedia.com.[10]

Osteoarthritis

Main article: Osteoarthritis

This keeps orthopaedic surgeons busy.

Aneurysmal bone cyst

  • Abbreviated ABC.
Also see giant cell reparative granuloma (AKA solid aneurysmal bone cyst).

General

Features:[11]

  • Benign.
    • May grow rapidly.
  • Osteolysis -> cystic space -> filled with blood.
  • Relatively common; in children second only to osteosarcoma.[12]

Microscopic

Features:[11]

  • Bony trabeculae or osteoid tissue.
  • Osteoclast giant cells.
    • Multi-nucleated giant-cells with round randomly arranged nuclei.
  • Benign spindle cells (fibroblasts) - surround bone/adjacent to the giant cells - important.
  • Blood +/- surrounded by giant cells.

DDx:

Images:

Myositis ossificans

  • AKA fibro-osseous pseudotumour of digits.[13]

General

Epidemiology:

  • Young people.
  • History of trauma - typically.
  • Extremities - digits (fingers, toes).

Notes:

  • Histologically "worrisome" (for malignancy) - due to high cellularity.[13]

Microscopic

Features:[13]

  • High cellularity.
  • Low mitotic activity.
  • No atypical mitoses.
  • No hyperchromasia.

Other features:[14]

  • Low power diagnosis:
    • Lesion is well-circumscribed.
    • Normal muscle is adjacent to the lesion - key feature.

Images:

Paget disease of the bone

General

Classically divided into three phases:[18][19]

  1. Lytic (predominantly osteoclasts).
  2. Mixed lytic (osteoclastic) and blastic (osteoblastic).
  3. Sclerotic (burned-out).

Clinical

Presentation:[15]

  • Fracture.
  • Bone pain.
  • Bony deformity.
  • Deafness.
  • Incidental finding - radiologic or biochemical.

Serology:

  • Elevated ALP.

Microscopic

Features:[18]

  • Bone matrix has jigsaw-puzzle like pattern.
    • Jigsaw-puzzle pieces each ~ 100-500 micrometres in size (largest dimension).
  • Increased osteoclast activity.
    • Osteoclast = macrophage that reabsorbs bone matrix.

Images:

Fibrous dysplasia

  • AKA osteitis fibrosa.

General

Classification:

  • Monostotic - one bone involved, ~80% of cases.
  • Polyostotic - several bones involved, ~20% of cases.

Microscopic

Features:[20]

  • Woven bone with odd irregular shapes - key feature.
    • Described as "chinese characters".[21]
  • Fibrous tissue around bone.

Notes:

  • No osteoblastic rimming.

DDx:

Images:

Desmoplastic fibroma

General

  • Rare.

Microscopic

Features:[22]

  • Lamellar bone.
  • Fibrotic marrow space with:
    • Collagen.
    • Low cellularity.
    • Spindle cells without significant atypia.

DDx:

Gaucher disease

Main article: Gaucher disease

General

  • May present as a fracture.

Microscopic

  • Macrophages in the marrow space with a "crumpled tissue paper" appearance.

Langerhans cell histiocytosis of bone

  • AKA eosinophilic granuloma of bone.
Main article: Langerhans cell histiocytosis

General

  • Rare.
  • Children.

Microscopic

Features:

  • Eosinophils.
  • Cerebriform and/or reniform macrophages.

Giant cell reparative granuloma

General

  • Lesion of the mandible and maxilla.[23]

Radiology

  • Lytic lesion.

Microscopic

Features:[23]

  • Giant cells.
  • Fibroblasts.
  • Osteoid.
  • Hemosiderin-laden macrophages.

DDx:

Images:

Molecular

Recurrent chromosomal translocation:[24]

  • t(16;17)(q22;p13).

Osteopetrosis

General

  • Rare.
  • Genetic - may be autosomal dominant, autosomal recessive or X-linked.[25]
  • Pancytopenias - due to oblieration of the marrow space.
  • Fractures.
  • Radiologic diagnosis.

Gross

  • Marbled appearance.
  • Obliteration of the marrow space.

Image:

Microscopic

Features:[26]

  • Abundant irregular (pink) bony trabeculae with layers of (blue-gray) cartilage.

Image:

Osteoporosis

General

  • Very common.

Microscopic

Features:

See also

References

  1. ↑ Lin DD, Gailloud P, McCarthy EF, Comi AM (February 2006). "Oromaxillofacial osseous abnormality in Sturge-Weber syndrome: case report and review of the literature". AJNR Am J Neuroradiol 27 (2): 274–7. PMID 16484391.
  2. ↑ URL: http://www.life.umd.edu/classroom/bsci423/song/Lab1.html. Accessed on: 28 March 2012.
  3. ↑ IAV. 26 Feb 2009.
  4. ↑ URL: http://emedicine.medscape.com/article/199003-overview. Accessed on: 28 March 2012.
  5. ↑ http://emedicine.medscape.com/article/199003-overview
  6. ↑ http://upload.wikimedia.org/wikipedia/commons/6/69/Hematopoiesis_%28human%29_diagram.png
  7. ↑ Iancu, D.; Hao, S.; Lin, P.; Anderson, SK.; Jorgensen, JL.; McLaughlin, P.; Medeiros, LJ. (Feb 2007). "Follicular lymphoma in staging bone marrow specimens: correlation of histologic findings with the results of flow cytometry immunophenotypic analysis.". Arch Pathol Lab Med 131 (2): 282-7. doi:10.1043/1543-2165(2007)131[282:FLISBM]2.0.CO;2. PMID 17284114.
  8. ↑ URL: http://radiopaedia.org/articles/hyperostosis_frontalis_interna. Accessed on: 29 September 2010.
  9. ↑ Alabi, ZO.; Ojo, OS.; Odesanmi, WO. (1991). "Secondary amyloidosis in chronic osteomyelitis.". Int Orthop 15 (1): 21-2. PMID 2071276.
  10. ↑ URL: http://radipedia.com/WikiMedia/index.php?title=Benign_cystic_bone_lesions. Accessed on: 15 March 2011.
  11. ↑ 11.0 11.1 URL: http://emedicine.medscape.com/article/1254784-overview. Accessed on: 4 February 2011.
  12. ↑ van den Berg H, Kroon HM, Slaar A, Hogendoorn P (2008). "Incidence of biopsy-proven bone tumors in children: a report based on the Dutch pathology registration "PALGA"". J Pediatr Orthop 28 (1): 29–35. doi:10.1097/BPO.0b013e3181558cb5. PMID 18157043.
  13. ↑ 13.0 13.1 13.2 Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 607. ISBN 978-0781765275.
  14. ↑ IAV. 9 December 2010.
  15. ↑ 15.0 15.1 15.2 Britton, C.; Walsh, J. (Mar 2012). "Paget disease of bone - an update.". Aust Fam Physician 41 (3): 100-3. PMID 22396921.
  16. ↑ Hoch, B.; Hermann, G.; Klein, MJ.; Abdelwahab, IF.; Springfield, D. (Oct 2007). "Giant cell tumor complicating Paget disease of long bone.". Skeletal Radiol 36 (10): 973-8. doi:10.1007/s00256-007-0310-x. PMID 17437100.
  17. ↑ Karakida, K.; Ota, Y.; Aoki, T.; Akamatsu, T.; Kajiwara, H.; Hirabayashi, K. (Sep 2010). "Multiple giant cell tumors in maxilla and skull complicating Paget's disease of bone.". Tokai J Exp Clin Med 35 (3): 112-7. PMID 21319038.
  18. ↑ 18.0 18.1 URL: http://emedicine.medscape.com/article/311688-overview. Accessed on: 25 December 2010.
  19. ↑ URL: http://radiopaedia.org/articles/paget-disease-of-bone-1. Accessed on: 25 December 2010.
  20. ↑ URL: http://www.pathologypics.com/pictview.aspx?id=104. Accessed on: 14 April 2011.
  21. ↑ URL: http://www.pathcases.com/bone_tumors_and_tumor.htm. Accessed on: 31 May 2011.
  22. ↑ URL: http://www.bonetumor.org/tumors-fibrous-tissue/desmoplastic-fibroma. Accessed on: 14 April 2011.
  23. ↑ 23.0 23.1 23.2 Shah UA, Shah AK, Kumar S. Giant cell reparative granuloma of the jaw: A case report. Indian J Radiol Imaging [serial online] 2006 [cited 2012 Feb 28];16:677-8. Available from: http://www.ijri.org/text.asp?2006/16/4/677/32297.
  24. ↑ 24.0 24.1 Pan, Z.; Sanger, WG.; Bridge, JA.; Hunter, WJ.; Siegal, GP.; Wei, S. (Jan 2012). "A novel t(6;13)(q15;q34) translocation in a giant cell reparative granuloma (solid aneurysmal bone cyst).". Hum Pathol. doi:10.1016/j.humpath.2011.10.003. PMID 22285042.
  25. ↑ 25.0 25.1 Stark, Z.; Savarirayan, R. (2009). "Osteopetrosis.". Orphanet J Rare Dis 4: 5. doi:10.1186/1750-1172-4-5. PMC 2654865. PMID 19232111. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2654865/.
  26. ↑ 26.0 26.1 McMahon, C.; Will, A.; Hu, P.; Shah, GN.; Sly, WS.; Smith, OP. (Apr 2001). "Bone marrow transplantation corrects osteopetrosis in the carbonic anhydrase II deficiency syndrome.". Blood 97 (7): 1947-50. PMID 11264157.
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