GISTs and Neuroendocrine Tumors Flashcards

Flashcards based on the lecture notes about GISTs and Neuroendocrine tumors.

What is a GIST?

Gastrointestinal stromal tumor, the most common type of sarcoma

GIST Origin

A tumor of the interstitial cells of Cajal (ICC)

Common Locations of GISTs

Stomach, small intestine, large intestine, and rectum

Origin of GISTs

Interstitial cells of Cajal within the myenteric plexus of the muscularis propria

Most Common Site of GIST

Stomach (60%), followed by the ileum and jejunum (30%)

Micro/Mini/Subclinical GIST

Minute growths (1-10mm) of interstitial cells of Cajal/GIST-like cells

M:F Ratio in GIST Cases

1.1 (no clear sex predilection)

Mean Age at GIST Diagnosis

60-65 years old

Pathogenesis of GISTs

Mutations of gene encoding tyrosine kinase C-KIT (75-80%)

Role of Tyrosine Kinase C-KIT

receptor for stem cell factor

Alternative Mutation in GISTs

Activate a related tyrosine kinase, platelet-derived growth factor receptor A (PDGFRA) (5%)

Common Stem Cell with GISTs

Interstitial cells of Cajal

Location of Interstitial cell of Cajal

Express c-KIT and are located in the muscularis propria

Most Common Presentation of GIST

Gastrointestinal bleeding or abdominal pain

CT Scan Appearance of GIST

Solid, heterogeneous mass

Endoscopy Appearance of GIST

Subepithelial lesion

Endoscopic Ultrasound Appearance of GIST

Hypoechoic solid mass

Definitive Diagnosis of GIST

Histologic examination and immunohistochemistry

Most Specific Marker for GIST

DOG1

Most Useful Marker for GIST

c-KIT (CD117)

Primary Treatment for GISTs

Surgical resection

Imatinib Mesylate (Gleevec)

Tyrosine kinase inhibitor of KIT and PDGFRα

Intraoperative Tumor Rupture Association

Poor prognosis

Complete Surgical Resection Outcome

Improves local recurrence rate and overall survival

Incomplete Resection Association

Higher risk of recurrence

Neuro-endocrine Tumors (NETs)

Derived from neuro-endocrine cells in many organs

NETs Associated with:

Genetic cancer syndromes, such as von Hippel–Lindau (VHL) syndrome, Multiple endocrine tumour (MEN 1) ,Tuberous sclerosis and neurofibromatosis type 1

NET Initial Symptoms

Diarrhea and GI symptoms

Prognosis Factors

Tumour size, mitotic rate, site of origin

Optimal management of pancreatic endocrine tumors

surgical resection of the primary lesion