Difference between revisions of "Bone"

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


==Normal==
=Normal bone=
==Bone==
*Normal bone has osteocytes.
*Normal bone has osteocytes.
**If the osteocytes are missing... the bone is dead.
**If the osteocytes are missing... the bone is dead.
Line 11: Line 12:


Memory device: 'b' before 'c'.
Memory device: 'b' before 'c'.
==Hyperostosis frontalis interna==
*Extra-thick frontal bone.<ref>URL: [http://radiopaedia.org/articles/hyperostosis_frontalis_interna http://radiopaedia.org/articles/hyperostosis_frontalis_interna]. Accessed on: 29 September 2010.</ref>
*No clinical significance -- just has to be recognized as a "nothing".


==Bone marrow==
==Bone marrow==
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*Immature hematopoeitic cells adjacent to the bone.
*Immature hematopoeitic cells adjacent to the bone.


==Infectious==
=Benign variants=
===Osteomyelitis===
==Hyperostosis frontalis interna==
*Extra-thick frontal bone.<ref>URL: [http://radiopaedia.org/articles/hyperostosis_frontalis_interna http://radiopaedia.org/articles/hyperostosis_frontalis_interna]. Accessed on: 29 September 2010.</ref>
*No clinical significance -- just has to be recognized as a "nothing".
 
=Infections=
==Osteomyelitis==
General
General
*Hematogenous - often in children.
*Hematogenous - often in children.
*Direct entry (skin defect) - adults with diabetes.
*Direct entry (skin defect) - adults with diabetes.


====Microscopic====
===Microscopic===
*PMNs.
*[[PMN]]s.


===Chronic osteomyelitis===
==Chronic osteomyelitis==
*Plasma cells.
*Plasma cells.
**May be sterile, i.e. no organisms.
**May be sterile, i.e. no organisms.


==Bone tumours==
=Bone tumours=
{{Main|Bone tumours}}
{{Main|Bone tumours}}
This is a big topic.  It is dealt with in a separate article.   
This is a big topic.  It is dealt with in a separate article.   
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The bone tumour article covers tumour mimics, e.g. brown cell tumour.
The bone tumour article covers tumour mimics, e.g. brown cell tumour.


==Fractures==
=Fractures=
{{Main|Forensic pathology}}
{{Main|Forensic pathology}}
This is dealt with in the ''forensic pathology'' article.
This is dealt with in the ''forensic pathology'' article.


==Others==
=Others=
The following is a collection of weird stuffs.
The following is a collection of weird stuffs.


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*[http://commons.wikimedia.org/wiki/File:Paget_disease_of_bone_-_intermed_mag.jpg Paget disease - bone - intermed. mag. (WC)].
*[http://commons.wikimedia.org/wiki/File:Paget_disease_of_bone_-_intermed_mag.jpg Paget disease - bone - intermed. mag. (WC)].


==See also==
=See also=
*[[Hematopathology]].
*[[Hematopathology]].
*[[Soft tissue lesions]].
*[[Soft tissue lesions]].
Line 125: Line 127:
*[[Cartilage]].
*[[Cartilage]].


==References==
=References=
{{reflist|2}}
{{reflist|2}}


[[Category:Weird stuff]]
[[Category:Weird stuff]]

Revision as of 06:29, 1 January 2011

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

  • Normal bone has osteocytes.
    • If the osteocytes are missing... the bone is dead.
  • Osteoblasts - make bone.
  • Osteoclasts - destroy bone.

Memory device: 'b' before 'c'.

Bone marrow

Main article: Haematopoiesis
  • Fat content (%) ~= age (in years)[1]
    • e.g. 60 year old will have 60% fatty replacement.
  • Should see three cell lines.
    • The cell lines:[2]
      • Erythroid (red cells),
      • Myeloid (white blood cells),
      • Megakaryocytic (platelets).

Note: Lymphocytes are considered separately and typically spared in bone marrow failure.[3]

Identifying the lines:[4]

  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.

Benign variants

Hyperostosis frontalis interna

  • Extra-thick frontal bone.[5]
  • 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

  • Plasma cells.
    • May be sterile, i.e. no organisms.

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: Forensic pathology

This is dealt with in the forensic pathology article.

Others

The following is a collection of weird stuffs.

Myositis ossificans

  • AKA fibro-osseous pseudotumour of digits.[6]

General

Epidemiology:

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

Notes:

  • Histologically "worrisome" (for malignancy) - due to high cellularity.[6]

Microscopic

Features:[6]

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

Other features:[7]

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

Paget disease of the bone

General

Classically divided into three phases:[8][9]

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

Clinical:

  • Elevated ALP.

Microscopic

Features:[8]

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

Images:

See also

References

  1. ↑ IAV. 26 Feb 2009.
  2. ↑ http://emedicine.medscape.com/article/199003-overview
  3. ↑ http://emedicine.medscape.com/article/199003-overview
  4. ↑ http://upload.wikimedia.org/wikipedia/commons/6/69/Hematopoiesis_%28human%29_diagram.png
  5. ↑ URL: http://radiopaedia.org/articles/hyperostosis_frontalis_interna. Accessed on: 29 September 2010.
  6. ↑ 6.0 6.1 6.2 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.
  7. ↑ IAV. 9 December 2010.
  8. ↑ 8.0 8.1 URL: http://emedicine.medscape.com/article/311688-overview. Accessed on: 25 December 2010.
  9. ↑ URL: http://radiopaedia.org/articles/paget-disease-of-bone-1. Accessed on: 25 December 2010.
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