Chondro-osseous tumours

From Libre Pathology
Revision as of 20:19, 18 August 2010 by Michael (talk | contribs) (→‎See also: SRBCT)
Jump to navigation Jump to search

Bone occasionally crosses the desk of the pathologist. Primary bone tumours are rare; the most common bone tumour is metastases.[1]

Bone tumours occasionally are lumped with soft tissue tumours. Soft tissue tumours are dealt with in the soft tissue lesions article.

Normal

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

Memory device: 'b' before 'c'.

Diagnosing bone tumours

  • Diagnosis should not be made without radiologic & clinical information.

Bone marrow

  • Fat content (%) ~= age (in years)[2]
    • e.g. 60 year old will have 60% fatty replacement.
  • Should see three cell lines.
    • The cell lines:[3]
      • Erythroid (red cells),
      • Myeloid (white blood cells),
      • Megakaryocytic (platelets).

Note: Lymphocytes are considered separately and typically spared in bone marrow failure.[4]

Identifying the lines:[5]

  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.

Infectious

Osteomyelitis

General

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

Microscopic

  • PMNs.

Chronic osteomyelitis

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

Bone tumours

General

  • Metastasis:primary bone tumours = >20:1.[6]

Common malignant

  • Osteosarcoma.
  • Chondrosarcoma.
  • Ewing's sarcoma.
  • Multiple myeloma.
  • Metastases.
    • Most common tumours metastatic to bone (mnemonic: BLT with Ketchup & Pickles):
      • Breast.
      • Liver.
      • Thyroid.
      • Kidney.
      • Prostate.

Epidemiology:[7]

  • Osteosarcoma -> 2nd decade.
  • Ewing's ->5-20 yrs.
  • Chondrosarcoma -> from enchondroma or osteochrondroma -- patients over 40 yrs.
  • Multiple myeloma -> most common primary bone tumour in adults.

Malignant bone tumours by age

Most common by age:[8]

  • <1 year old - neuroblastoma.
  • 1-10 years old - Ewing's of tubular bones.
  • 10-30 years old - osteosarcoma, Ewing's of flat bones.
  • 30-40 years old - reticulum cell sarcoma, fibrosarcoma, parosteal osteosarcoma, malignant giant cell tumour, lymphoma.
  • >40 years old - mets, multiple myeloma, chondrosarcoma.

Benign aggressive bone tumours

  • Giant cell tumours.
  • Osteoblastoma.
    • Thought to be related to osteoid osteoma.
    • If in long bones often diaphyseal.

Ref.:[9][10]

Giant cell tumour

General

Features:[11]

  • Approximately 5% of primary bone tumours.
  • Typical age: 20-45 years.

Clinical

  • May present with joint pain, immobility.

Microscopic

Features:[12]

  • Giant cells.
  • Mononuclear cells, with nuclei similar to those in giant cells - key feature

Chondrosarcoma

Micro

Features:[13]

  • Abnormal cartilage.
  • Nuclear atypia.
    • Nuclear clearing.
    • Nucleoli.

Ewing sarcoma

General

  • AKA EWS/PNET:
    • EWS = Ewing sarcoma.
    • PNET = Primative neuroectodermal tumour.
  • EWS and PNET were once thought to be different tumours.

Clinical

  • Painful.
  • Usually younger than 20 years.

Radiology

Features:[14]

  • Long bones, diaphyses.
  • Destructive.
  • "Onion-skin" periosteal reaction.

Microscopic

Classification:

  • Small blue cell tumour.

Features:[15]

  • Scant clear cytoplasm (contain glycogen - PAS +ve, PAS-D -ve).
  • Lack nucleoli.
  • Round small nucleus.

IHC

Features:[16]

  • CD99 +ve (plasma membrane staining).
  • CD45 -ve.
    • Done to r/o lymphoma.
  • +/-Neural markers (NSE, synaptophysin, CD57 (??? CD56 ???), S100).
  • +/-Cytokeratins.
  • Caveolin-1[17]
    • New kid on the block.

Notes:[18]

  • CD99 +ve (plasma membrane) tumours:
    • Lymphoblastic lymphoma/leukemia.
    • Angiomatoid fibrous histiocytoma.
    • Desmoplastic small round cell tumour.

Molecular diagnostics

Common features:

  • EWS/FLI-1 fusion gene formation due to translocation: t(11;22)(q24;q12).[19][20]
    • Often detected by RT-PCR (with EWS 5' and FLI-1 3' primers).

Notes:

  • The t(11;22)(q24;q12) is seen in ~90% of EWS/PNET... but also in:
    • Olfactory neuroblastoma.
    • Small cell osteogenic sarcoma.
    • Polyphenotypic tumours.
    • Rhbdomyosarcoma.
    • Neuroblastoma (possibly).
  • Several other translocations exist.

Osteosarcoma

General

  • Terry Fox was afflicited by this tumour.

Definition

  • Tumour that makes osteoid.
    • Osteoid = (extracellular) organic component of bone, normally produced by osteoblasts (cells which make bone matrix).

Histology

  • Spindle cells with malignant features (e.g. nuclear membrane irregularies, marked nuclear size differences, mitoses) surrounded by delicate strands of osteoid.
    • Osteoid on H&E: pink, homogenous, "glassy".
    • Tumours typically very cellular - when compared to normal bone.
  • Large (multinucleated) osteoclast-like giant cells may be seen.[21]

Other

Pigmented villonodular synovitis

  • Commonly abbreviated: PVNS.
  • Course: benign.

Microscopy

Features:[22]

  • Subsynovial nodules composed of cells with:
    • Abundant cytoplasm.
    • Pale nuclei.
  • Multinucleated giant cells.
  • Hemosiderin-laden macrophages.
  • Foam cells.

Adamantinoma

General

Features:[23]

  • Rare: < 1% of bone tumours.
  • 25-35 years old.
  • Tibia, fibula.
  • Benign, may be locally aggressive.
  • Cousin of ameloblastoma.[24]

Radiology

  • Intracortical, radiolucent.

Microscopic

Features:

  • Fibrous tumour.

Brown cell tumour

Etiology

  • Due to hyperparathyroidism - usually parathyroid adenoma.

Microscopy

Features:

  • Fibrosis.

Hypercalcemia DDx

Mnemonic GRIMED:[25]

  • Granulomatous disease (tuberculosis, sarcoidosis).
  • Renal disease.
  • Immobility.
  • Malignancy (esp. squamous cell carcinoma, plasmacytoma).
  • Endocrine (primary hyperparathyroidism - leads to brown cell tumour).
  • Drugs (thiazides ... others).

See also

References

  1. WMSP P.632
  2. IAV 26 Feb 09
  3. http://emedicine.medscape.com/article/199003-overview
  4. http://emedicine.medscape.com/article/199003-overview
  5. http://upload.wikimedia.org/wikipedia/commons/6/69/Hematopoiesis_%28human%29_diagram.png
  6. WMSP P.632.
  7. TN05 OR42.
  8. TN05 OR42.
  9. TN05 OR41.
  10. URL: http://www.emedicine.com/RADIO/topic494.htm.
  11. WMSP P.648.
  12. Klatt. AOP P.420.
  13. IAV. 26 February 2009.
  14. WMSP P.650.
  15. PST. 22 February 2010.
  16. WMSP P.651.
  17. PST. 22 February 2010.
  18. PST. 22 February 2010.
  19. URL: http://atlasgeneticsoncology.org/Tumors/Ewing5010.html. Accessed on: 23 February 2010.
  20. PMID: 3163261
  21. Papalas JA, Balmer NN, Wallace C, Sangueeza OP (June 2009). "Ossifying dermatofibroma with osteoclast-like giant cells: report of a case and literature review". Am J Dermatopathol 31 (4): 379-83. doi:10.1097/DAD.0b013e3181966747. PMID 19461244.
  22. http://www.wheelessonline.com/ortho/pigmented_villonodular_synovitis
  23. WMSP P.650.
  24. NEED REF.
  25. TN06 Emerg