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
what is the treatment of gist ?
gist smaller than 2 cm = endoscopic removal if in the stomach
other location removed through surgical resection
larger GIST
surgical excision with adjuvant treatment of imatinib
palliative treatment using imatinib if the timor is not resectable and metastasis has occurred
what is imatinib ?
tyrosine kinase inhibotr - the gist tumor has a muation in the kit tyrosine kinase inhibitor
what isthe staging of gist ?
t1 - smaller than 2cm localised
t2 - 2-5cm
t3 = 5-10 cm
t4 == greater than 10 cm
