8936/3 Gastrointestinal stromal tumor, malignant



Definitions

Stomach
ICD-O-3 topography code: C16
ICD10: C16
           

A malignant subtype of gastrointestinal stromal tumor (GIST) characterized by large size (diameter more than 2 cm and often greater than 10cm) and more than 5 mitotic figures per 50 high power fields.

For general comments on gastric GISTs, please see GIST, NOS.



Colon and rectum
ICD-O-3 topography code: C18-C20
ICD10: C18-C20
           

The term gastrointestinal stromal tumour (GIST) is used for a specific group of tumours comprising the majority of gastrointestinal mesenchymal tumours, including those previously termed leiomyoma, cellular leiomyoma, leiomyoblastoma and leiomyosarcoma 1
 
Hamilton SR, Aaltonen LA (Eds.)
World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of the Digestive System.
3rd Edition
IARC Press: Lyon 2000



. Rare cases involving tissues outside the gastrointestinal tract have also been reported (extragastrointestinal gastrointestinal stromal tumors). GIST are KIT-expressing and KIT-signaling-driven mesenchymal tumors that repsond favourably to treatment with the KIT tyrosine kinase inhibitor imatinib mesylate / Gleevec 2
Click to access Pubmed
Druker BJ (2004)
Imatinib as a paradigm of targeted therapies.
Adv Cancer Res 91: 1-30



.
Malignant GIST is a subtype of gastrointestinal stromal tumor characterized by large size (diameter greater than 10cm) and more than 5 mitotic figures per 50 high power fields.

GISTs of the colon and rectum
GISTs are very rare in the colon (about 1% of all GISTs) and have a predilection for the sigmoid. However, microscopic GISTs have been detected in 0.2% of retrospectively examined sigmoid-colon resections. Rectal GISTs comprise 4% of all GISTs and occur in any segment. These tumours vary from incidentally detected small mural nodules to large, complex pelvic masses that can cause intestinal obstruction or gastrointestinal bleeding. Those with anterior extension can abut the prostate gland and clinically simulate prostate cancer
3
Click to access Pubmed
Agaimy A, WŁnsch PH, Dirnhofer S, Bihl MP, Terracciano LM, Tornillo L (2008)
Microscopic gastrointestinal stromal tumors in esophageal and intestinal surgical resection specimens: a clinicopathologic, immunohistochemical, and molecular study of 19 lesions.
Am J Surg Pathol 32: 867-73



4
Click to access Pubmed
Hassan I, You YN, Shyyan R, Dozois EJ, Smyrk TC, Okuno SH, Schleck CD, Hodge DO, Donohue JH (2008)
Surgically managed gastrointestinal stromal tumors: a comparative and prognostic analysis.
Ann Surg Oncol 15: 52-9



5
Click to access Pubmed
Miettinen M, Furlong M, Sarlomo-Rikala M, Burke A, Sobin LH, Lasota J (2001)
Gastrointestinal stromal tumors, intramural leiomyomas, and leiomyosarcomas in the rectum and anus: a clinicopathologic, immunohistochemical, and molecular genetic study of 144 cases.
Am J Surg Pathol 25: 1121-33



6
Click to access Pubmed
Miettinen M, Sarlomo-Rikala M, Sobin LH, Lasota J (2000)
Gastrointestinal stromal tumors and leiomyosarcomas in the colon: a clinicopathologic, immunohistochemical, and molecular genetic study of 44 cases.
Am J Surg Pathol 24: 1339-52



.
Most colonic GISTs are advanced tumours when detected, and have a poor prognosis. The behaviour of rectal GISTs is often aggressive, and even small tumours of < 2 cm in size with mitotic activity can recur and metastasize. Pelvic extension and liver metastasis is common, and bone metastases may develop more often than in gastric and small-intestinal GISTs
7
 
Bosman FT, Carneiro F, Hruban RH, Theise ND (Eds.)
WHO Classification of Tumours of the Digestive System.
4th Edition
International Agency for Research on Cancer: Lyon 2010



.



Esophagus
ICD-O-3 topography code: C15
ICD10: C15.9
           

This is a malignant subtype of gastrointestinal stromal tumor characterized by large size (diameter greater than 10cm) and more than 5 mitotic figures per 50 high power fields.

GISTs are very rare in the oesophagus and comprise 10?20% of the combined group of smooth-muscle and stromal tumours. Most are clinically detected as intraluminal distal oesophageal masses causing dysphagia, but externally extending oesophageal GISTs can manifest as mediastinal tumours.
Occasional examples have been incidentally detected during radiological screening or surveillance studies, and such tumours can have a good prognosis, an exception among this group of tumours, among which sarcomas predominate
8
 
Bosman FT, Carneiro F, Hruban RH, Theise ND (Eds.)
WHO Classification of Tumours of the Digestive System.
4th Edition
International Agency for Research on Cancer: Lyon 2010



.



Small intestine
ICD-O-3 topography code: C17
ICD10: C17
           

A malignant subtype of gastrointestinal stromal tumor characterized by large size (diameter greater than 10cm) and more than 5 mitotic figures per 50 high power fields.



Connective, subcutaneous and other soft tissues
ICD-O-3 topography code: C49
ICD10: C49
           

A malignant subtype of gastrointestinal stromal tumor characterized by large size (diameter greater than 10cm) and more than 5 mitotic figures per 50 high power fields.