Gastrointestinal stromal tumours (GIST). MALT lymphoma of the stomach Flashcards
gastric malt (mucosa associated lymphoid tissue) lymphoma is what type of lymphoma ?
non hodgkin gastric lymphoma
what is the etiology of malt lymphoma of stomach ?
h pylori
what are examples of MALT (mucosa associated lymphoid tissue) tissue ?
two types of MALT tissue
NATIVE - normally there
tonsils
peters patches within small intestine
most prominent - terminal ileum Peters patch
vermiform appendix
ACQUIRED MALT - lymphoid tissue is not a natural component
hashimoto
H pylori gastritis
what is the pathophsyiolog of MALT lymphoma ?
helicobacter pylori gastritis
t cells and b cels activated for antibodies
neutrophils prooductionof reactive oxygen species = damage to DNA of b cells
>
B cells abnormal cloning (trisomy 3) translocationof 11 and 18
>
early low grade malt lymphoma - h pylori dependant
>
late low grade malt lymphoma (h pylori independent )
> high grade Malt lymphoma
what are the features suggesting an antigen driven growth of MALT lymphoma ?
histological factures
reactive lymphoid follicle and follicular colonisation
scattered transformed cells in cell cycle
plasma cell differentiation
intratumoral t cells
what is the standard staging of malt lymphoma ?
stage 1 - lymphoma restricted to stomach and one side of diaphragm
stage 2 - lymphoma infiltrating lymph nodes of the same side of the diaphragm
A regional
B non regional
stage 3 - lymph nodes affected on both sides of the diaphragm
stage 4
diffuse and disseminated involvement of the extra GI organs
what is used to diagnose MLAT lymphoma ?
endosonography gastroscopy with multiple biopsies
immunochemistry postive CD20 CD43
negative CD5 AND CD10
cytogenic an molecular test = especially translocation of
11 and 18
q21;q21
using FISH and PCR
H pylori testing
what is the treatment for primary gastric lymphoma ?
surgery followed by chemotherapy and radiotherapy
low grade primary gastric malt lymphoma can completely regress when ?
eradicaionof h pyylori
however advanced tumor stage such as stage 2 or high grade malignancy dd not respond to h pylori eradication
suscceful also only if tumor is absent in the lymph nodes
and hasn’t spread to stomach wall
t (11:18) patients seems to be unresponsive to hp eradication therapy
where does gastrointestinal stromal tumors arise from ?
MALIGNANT mesenchymAL TUMORS
from the interstitial cells of CAJAL in the normal myenteric plexus
what is the median age of diagnosis for GIST ?
66-69 years
what is the median size of presentation of GIST ?
5cm
what is the localisation of most of the GIST tumors
50percent the stomach
small intestine 25 percent
colon and rectum 10 parent
small intestine = 10 percent
what is the clinical presentation of GIST ?
DEPENDS ON THE SITE AND size
smaller than 2 cm usually asymptomatic
or unspecific if long term = early satiety , fatigue , secondary anemia
large tumors may cause ulceration , bleeding , obstruction bleeding to ileum
abdominal mass
pain in the abdomen
abdominal distension
emergency - acute abdomen
if there is tumor rupture / gastrointestinal obstruction / appendicitis like pain
what is the diagnosis of GIST ?
MRI rectal GIST
CT
small tumor = endoscopic ultrasound
guided fine needle aspiration
biopsy and excision if nodules more than 2 cm usually associated with malignancy or progression and esp if its outside the stomach
histopathology
most commonly located in the muscular propria
ulceration 50 percent
if metastatic - percutaneous image guided biopsy
