SPONSORED FEATURE
Gastrointestinal Stromal Tumor ( GIST ): From an indolent tumor to cancer
Endoscopy appearance of stomach GIST CT imaging of stomach GIST
Histology appearance of positive CD 117 - GIST
Gastrointestinal stromal tumor ( GIST ) is the most common mesenchymal neoplasms and accounts for 20 % of all soft tissue tumors of the gastrointestinal tract . GISTs arise in the smooth muscle pacemaker ‘ interstitial cell of Cajal ’ and occur most commonly in the stomach or small intestine . GISTs rarely arise within the abdominal cavity without an apparent connection to the GI tract . Most GISTs are sporadic . However , some cases are related to rare genetic mutations such as Neurofibromatosis type 1 , Carney-Stratakis syndrome , and Carney triad .
Clinical spectrum GISTs occur at any age , with a median age at detection of 65 years , but they rarely occur in individuals younger than age 20 years . GIST occurs with similar frequency in males and females . The clinical presentation largely depends on the tumor molecular characteristics , ranging from a slow growing benign tumor towards progressively advanced malignant cancers . Advanced disease may present as bleeding from the gastrointestinal tract . Bleeding may be slow , resulting in anemia , or sudden , causing tachycardia , fainting , stomach pain , melena , or hematemesis .
GISTs may cause other symptoms depending on size and location , such as abdominal pain , fullness or pressure , or bowel obstruction . Meanwhile asymptomatic GISTs may be detected by palpation , during endoscopy , imaging , or at surgery for other conditions .
Staging Standard imaging consists of computed tomography of the abdomen and pelvis . Imaging of the chest may be considered to exclude rare metastases above the diaphragm . Magnetic resonance imaging may provide additional information , particularly for GIST of the rectum or duodenum . Other examinations , such as computed tomography – positron emission tomography or ultrasound of the liver , may also be considered .
Diagnostic tools for GIST : � Endoscopy � CT scan � MRI � PET-CT
Definitive Tissue Diagnosis and Molecular Biology GIST morphology is variable , and immunohistochemical staining usually establishes the diagnosis . Most GISTs stain for C-KIT ( 95 %) and anoctamin-1 ( DOG-1 ; 98 %), whereas most do not stain with smooth muscle biomarkers such as desmin .
Activating mutations in KIT and PDGFRA ( encoding KIT and platelet-derived growth factor receptor tyrosine kinases , respectively ) are considered the main oncogenic drivers of GIST .
Immunohistochemical markers for GIST : - � C-KIT ( CD 117 ) � CD 34 � DOG-1
Surgery and targeted therapy Approximately 60 % of patients with localized GIST are cured with surgery . The aim is to completely excise GIST macroscopically and microscopically , without rupturing the tumor capsule . This can be done at open surgery or , for smaller tumors , by laparoscopic surgery . The main principle is to achieve negative margin and lymph node dissection is usually not indicated .
Tyrosine kinase inhibitors such as imatinib is used for adjuvant treatment and helps to improve overall patient survival .
Targeted therapy for GIST : - � Imatinib � Sunitinib � �egorafinib
Dr . Muhammad Khairil b . Ab Khalil , General Surgeon KMI Kelana Jaya Medical Centre
GlobalHealthAsiaPacific . com ISSUE 2 | 2024
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