Difference between revisions of "Gastrointestinal stromal tumour"

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==Microscopic==
==Microscopic==
Features:
Features:
*Classically, spindle cell morphology; however, may be epithelioid (round).
*Classically, spindle cell morphology ~ 50% of tumours.<ref name=pmid15613856>{{Cite journal  | last1 = Miettinen | first1 = M. | last2 = Sobin | first2 = LH. | last3 = Lasota | first3 = J. | title = Gastrointestinal stromal tumors of the stomach: a clinicopathologic, immunohistochemical, and molecular genetic study of 1765 cases with long-term follow-up. | journal = Am J Surg Pathol | volume = 29 | issue = 1 | pages = 52-68 | month = Jan | year = 2005 | doi =  | PMID = 15613856 }}</ref>
** May be epithelioid (round) ~40% of tumours.
** Mixed epithelioid and spindle cell tumours ~10% tumours.
*+/-Cytoplasmic inclusions.<ref name=pmid7757951>{{cite journal |author=Pasquinelli G, Severi B, Martinelli GN, Santini D, Gelli MC, Tison V |title=Gastro-intestinal stromal tumors: an ultrastructural reinterpretation of the clear cell component |journal=J. Submicrosc. Cytol. Pathol. |volume=27 |issue=2 |pages=251–7 |year=1995 |month=April |pmid=7757951 |doi= |url=}}</ref>
*+/-Cytoplasmic inclusions.<ref name=pmid7757951>{{cite journal |author=Pasquinelli G, Severi B, Martinelli GN, Santini D, Gelli MC, Tison V |title=Gastro-intestinal stromal tumors: an ultrastructural reinterpretation of the clear cell component |journal=J. Submicrosc. Cytol. Pathol. |volume=27 |issue=2 |pages=251–7 |year=1995 |month=April |pmid=7757951 |doi= |url=}}</ref>
*Classically splits the layers of the ''muscularis propria'' - as this is where the ''interstitial cells of Cajal'' are located.<ref name=pmid16402273>{{cite journal |author=Agaimy A, Wünsch PH |title=Gastrointestinal stromal tumours: a regular origin in the muscularis propria, but an extremely diverse gross presentation. A review of 200 cases to critically re-evaluate the concept of so-called extra-gastrointestinal stromal tumours |journal=Langenbecks Arch Surg |volume=391 |issue=4 |pages=322–9 |year=2006 |month=August |pmid=16402273 |doi=10.1007/s00423-005-0005-5 |url=}}</ref>
*Classically splits the layers of the ''muscularis propria'' - as this is where the ''interstitial cells of Cajal'' are located.<ref name=pmid16402273>{{cite journal |author=Agaimy A, Wünsch PH |title=Gastrointestinal stromal tumours: a regular origin in the muscularis propria, but an extremely diverse gross presentation. A review of 200 cases to critically re-evaluate the concept of so-called extra-gastrointestinal stromal tumours |journal=Langenbecks Arch Surg |volume=391 |issue=4 |pages=322–9 |year=2006 |month=August |pmid=16402273 |doi=10.1007/s00423-005-0005-5 |url=}}</ref>
*Skenoid fibres - extracellular collagen bundles<ref name=pmid15798063/> ~ 2-5 x 60 micrometers.
*+/-Skenoid fibres - extracellular collagen bundles<ref name=pmid15798063/> ~ 2-5 x 60 micrometers - uncommon finding.
**Uncommon finding.
**Not seen in gastric GISTs.<ref name=pmid12692202/>
***Not seen in gastric GISTs.<ref name=pmid12692202/>
**High [[specificity]] for GIST.
**High [[specificity]] for GIST.



Revision as of 01:12, 20 February 2013

The gastrointestinal stromal tumour, abbreviated GIST, is an uncommon tumour of the gastrointestinal tract.

General

Definition

  • Mutation in the Kit gene or PDGFRA (Platelet-derived growth factor receptor, alpha polypeptide) gene.[1]

Epidemiology

  • Arise from Interstitial cells of Cajal.[1]

May be familial/syndromic:[2]

Treatment

Factors predictive of malignant behaviour

Features suggesting a bad prognosis:[1]

  • Large size.
    • Often benign if small size.
  • High mitotic rate (for area 5mm^2).
  • Site - small intestine GISTs worse than stomach GISTs.

Small intestine bad prognosis:[1]

  • >5 mitoses/5 mm^2 or size >10 cm.

Stomach bad prognosis:[1]

  • >5 mitoses/5 mm^2 and size >5 cm.

Location

Most common locations in order:[1]

  • 60% in stomach.
  • 35% in small intestine.
  • 5% elsewhere.

Notes:

  • Small intestinal GISTs have a worse prognosis than gastric ones.[1]
  • GISTs almost never metastasize to the lymph nodes.

Microscopic

Features:

  • Classically, spindle cell morphology ~ 50% of tumours.[3]
    • May be epithelioid (round) ~40% of tumours.
    • Mixed epithelioid and spindle cell tumours ~10% tumours.
  • +/-Cytoplasmic inclusions.[4]
  • Classically splits the layers of the muscularis propria - as this is where the interstitial cells of Cajal are located.[5]
  • +/-Skenoid fibres - extracellular collagen bundles[6] ~ 2-5 x 60 micrometers - uncommon finding.

DDx

Images:

IHC

  • CD34 +ve in 70%.[1]
  • CD117 +ve in 95%.[1]
  • Desmin +ve in 5%.[1]
  • DOG1 +ve.[8]
    • More sensitive than CD117.

ICH Work-up panel

  • S-100 (neural tumours, rarely +ve in GISTs[1]).
  • CD34, CD117 (GIST).
  • Desmin (muscle tumours).

Molecular tests

See Molecular_pathology_tests#Other.
  • Sequence Kit gene, PDGFRA gene.
    • Kit gene sequencing is being done more frequently as of late-- if a mutation is found it suggest the drug imatinib will be effective.

See also

References

  1. 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 Miettinen M, Lasota J (October 2006). "Gastrointestinal stromal tumors: review on morphology, molecular pathology, prognosis, and differential diagnosis". Arch. Pathol. Lab. Med. 130 (10): 1466–78. PMID 17090188. http://journals.allenpress.com/jrnlserv/?request=get-abstract&issn=0003-9985&volume=130&page=1466.
  2. Agaimy A, Hartmann A (October 2010). "[Hereditary and non-hereditary syndromic gastointestinal stromal tumours]" (in German). Pathologe 31 (6): 430–7. doi:10.1007/s00292-010-1354-6. PMID 20848108.
  3. Miettinen, M.; Sobin, LH.; Lasota, J. (Jan 2005). "Gastrointestinal stromal tumors of the stomach: a clinicopathologic, immunohistochemical, and molecular genetic study of 1765 cases with long-term follow-up.". Am J Surg Pathol 29 (1): 52-68. PMID 15613856.
  4. Pasquinelli G, Severi B, Martinelli GN, Santini D, Gelli MC, Tison V (April 1995). "Gastro-intestinal stromal tumors: an ultrastructural reinterpretation of the clear cell component". J. Submicrosc. Cytol. Pathol. 27 (2): 251–7. PMID 7757951.
  5. Agaimy A, Wünsch PH (August 2006). "Gastrointestinal stromal tumours: a regular origin in the muscularis propria, but an extremely diverse gross presentation. A review of 200 cases to critically re-evaluate the concept of so-called extra-gastrointestinal stromal tumours". Langenbecks Arch Surg 391 (4): 322–9. doi:10.1007/s00423-005-0005-5. PMID 16402273.
  6. 6.0 6.1 6.2 Levy, AD.; Patel, N.; Dow, N.; Abbott, RM.; Miettinen, M.; Sobin, LH.. "From the archives of the AFIP: abdominal neoplasms in patients with neurofibromatosis type 1: radiologic-pathologic correlation.". Radiographics 25 (2): 455-80. doi:10.1148/rg.252045176. PMID 15798063.
  7. 7.0 7.1 Greenson, JK. (Apr 2003). "Gastrointestinal stromal tumors and other mesenchymal lesions of the gut.". Mod Pathol 16 (4): 366-75. doi:10.1097/01.MP.0000062860.60390.C7. PMID 12692202.
  8. Liegl, B.; Hornick, JL.; Corless, CL.; Fletcher, CD. (Mar 2009). "Monoclonal antibody DOG1.1 shows higher sensitivity than KIT in the diagnosis of gastrointestinal stromal tumors, including unusual subtypes.". Am J Surg Pathol 33 (3): 437-46. doi:10.1097/PAS.0b013e318186b158. PMID 19011564.