Gastrointestinal stromal tumour
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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]
- Neurofibromatosis 1 (von Recklinghausen's disease).
- Carney triad.
- Familial GIST syndrome (several).
- Others.
Treatment
- Imatinib (Gleevec) - drug was developed for chronic myelogenous leukemia.
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.
- Most common metastasis locations: liver, abdominal soft tissue.
Microscopic
Features:
- Classically, spindle cell morphology; however, may be epithelioid (round).
- +/-Cytoplasmic inclusions.[3]
- Classically splits the layers of the muscularis propria - as this is where the interstitial cells of Cajal are located.[4]
- Skenoid fibres - extracellular collagen bundles[5] ~ 2-5 x 60 micrometers.
- Uncommon finding.
- Not seen in gastric GISTs.[6]
- High specificity for GIST.
- Uncommon finding.
DDx
- Leiomyosarcoma.
- Leiomyoma - esp. in the esophagus.
- Neural tumours.
- Neurofibroma.
- Schwannoma (GFAP +ve).
- GFAP uniformly neg. in GISTs.[1]
- Desmoid-type fibromatosis.
Images:
- www:
- WC:
IHC
- CD34 +ve in 70%.[1]
- CD117 +ve in 95%.[1]
- Mast cells are the internal positive control.
ICH Work-up panel
- S-100 (neural tumours, rarely +ve in GISTs[1]).
- CD34, CD117 (GIST).
- Desmin (muscle tumours).
Molecular tests
- 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
- ↑ 1.00 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.
- ↑ 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.
- ↑ 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.
- ↑ 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.
- ↑ 5.0 5.1 5.2 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.
- ↑ 6.0 6.1 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.
- ↑ 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.