Term
| what is pyloric stenosis? what can it cause? who is it seen in? is it detectable on a physical exam? |
|
Definition
| pyloric stenosis is narrowing of the pyloric canal and obstruction of the gastric outlet. it can cause projectile vomiting in infancy and is more common in males and pts with *turner syndrome and *trisomy 18. it can sometimes be palpated as an abdominal mass on physical exam. |
|
|
Term
| what are the gross features of pyloric stenosis? microscopic features? |
|
Definition
gross: concentric pyloric enlargement.
microscopic: hypertrophy of circular muscle |
|
|
Term
| can pyloric stenosis result in loss of HCl? |
|
Definition
| yes, which may lead to hypochloremic alkalosis |
|
|
Term
| what generally characterizes acute hemorrhagic gastritis? |
|
Definition
| breakdown of the mucosal barrier, which can lead to hemorrhaging throughout the stomach. |
|
|
Term
| what are the different causes of acute hemorrhagic gastritis? |
|
Definition
| stress ulcers: curling and cushing. drug related: corticosteriods/ASA and NSAIDs |
|
|
Term
| how is acute hemorrhagic gastritis caused by a curling ulcer? |
|
Definition
| curling ulcers are the result of severe burns to the stomach (think curling iron) |
|
|
Term
| how is acute hemorrhagic gastritis caused by a cushing ulcer? |
|
Definition
| CNS lesion/trauma due to increased vagal tone and increased acid secretion. these types of ulcers tend to be multiple and a few mm in size each. |
|
|
Term
| how can anti-inflammatory drugs result in acute hemorrhagic gastritis? |
|
Definition
| corticosteroids, ASA, and other NSAIDs shut down the arachidonic acid pathway which produces prostaglandins which is necessary for protective mucus secretion in the stomach. |
|
|
Term
| how does acute hemorrhagic gastritis present macroscopically? |
|
Definition
| as *widespread petechial hemorrhage/hyperemia on the gastric surface with patchy mucosal and submucosal necrosis. |
|
|
Term
| on macroscopic view, can curling's and cushing's ulcers be differentiated? |
|
Definition
|
|
Term
| what are symptoms of acute hemorrhagic gastritis? |
|
Definition
| often minimal, but it can progress to gastric perforation and subsequent massive hemorrhage. |
|
|
Term
| can pts develop anemia with acute hemorrhagic gastritis? |
|
Definition
| yes, pts with acute hemorrhagic gastritis may develop hypochromic microcytic anemia |
|
|
Term
| what characterizes auto-immune gastritis? |
|
Definition
| a stomach affected by auto-immune gastritis will be atrophied in both the body and fundus, but *not the antrum or cardia*, antibodies will be formed to parietal cells and intrinsic factor (decreased acid secretion), and *G cell/endocrine cell hyperplasia of the antrum* - which results in both *increased serum gastrin and enterochromaffin-like cell hyperplasia. inflammatory infiltrate (lymphocytes/plasma cells) is usually seen and there may also be areas of intestinal metaplasia. |
|
|
Term
| what is the principal cause of autoimmune gastritis? |
|
Definition
| CD4 T cells are directed against parietal cells and H+, K+, and ATPase are principal agents of injury |
|
|
Term
| what is the result of auto-immune gastritis? |
|
Definition
| loss of parietal cells results in a decrease in both gastrin (over time) and intrinsic factor (IF). b/c of IF loss, pts develop a vit B12 deficiency. defective gastric acid secretion stimulates gastrin secretion. serum pepsinogen I concentration will also be reduced due to chief cell destruction. |
|
|
Term
| how do pts with autoimmune gastritis develop pernicious anemia? |
|
Definition
| w/out intrinsic factor, vit B12 is malabsorbed, leading to megaloblastic anemia |
|
|
Term
| what is peptic ulcer disease generally? |
|
Definition
| damage to the stomach and proximal duodenum due to gastric secretion of HCl |
|
|
Term
| what is peptic ulcer disease linked to? |
|
Definition
| peptic ulcer disease is linked to smoking, chronic gastritis, zollinger-elison syndrome, hyperparathyroidism and NSAIDs |
|
|
Term
| how common is malignant transformation in peptic ulcer disease? why is this important? |
|
Definition
| very rare and when CA is involved w/peptic ulcer disease, it is usually b/c the lesion was actually an ulcerated carcinoma. this is important b/c endoscopically, peptic ulcers can mimic gastric CA |
|
|
Term
| are people of a certain blood type predisposed to peptic ulcer disease? |
|
Definition
| yes, pts with type O blood are more at risk for duodenal peptic ulcers |
|
|
Term
| why are pepsinogen I circulating levels higher in pts with duodenal peptic ulcer disease? |
|
Definition
| b/c chief cell mass generally correlates with parietal cell mass |
|
|
Term
| what are familial tendencies associated with peptic ulcer disease pts? |
|
Definition
| a familial hyperfunction of antral G cells and associated secretion of gastrin -> leading to increased HCl secretion |
|
|
Term
| what is important about peptic ulcer disease in the duodenum? |
|
Definition
| there may be increased parietal cell mass/G cell hyperfunction, *accelerated gastric emptying - leading to excessive acidification of the duodenum from loss of inhibitory function as the lower pH overpowers the biliary/pancreatic/duodenal secretions. mucosal defenses will be impaired and pts present with *epigastric pain which decreases w/meals (acid is being put to use) - so pts may experience weight gain. |
|
|
Term
| morphologically, how do duodenal peptic ulcers generally present? |
|
Definition
| duodenal peptic ulcers stay close to the pylorus (ant/post walls) and are often *paired lesions in close proximity due to the narrow nature of the duodenum |
|
|
Term
| what are gastric peptic ulcers often associated with? where are they usually found? |
|
Definition
| gastric peptic ulcers are often associated with *H. pylori and chemical gastritis and are usually found near the pylorus. |
|
|
Term
| why are *most gastric peptic ulcers associated with HYPOsecretion of acid? |
|
Definition
| HCl over-secretion is not the cause of many ulcers, rather over-sensitivity of the gastric mucosa w/smaller amounts of acid. NSAIDs or other entities may injure the mucosa in this manner. |
|
|
Term
| what is the hyposecretion seen in gastric peptic ulcers linked to? |
|
Definition
| back diffusion of acid into the mucosa, decreased parietal cell mass or abnormalities in the parietal cells |
|
|
Term
| how do pts with gastric peptic ulcers present? |
|
Definition
| pts w/gastric peptic ulcers present with epigastric pain *after meals* and exhibit weight loss (opposite of duodenal peptic ulcers) |
|
|
Term
| morphologically, how do gastric peptic ulcers generally present? |
|
Definition
| gastric peptic ulcers are usually *single, less than 2 cm and found on the *lesser curvature when associated w/chronic gastritis and on the *greater curvature when associated with NSAIDs. gastric peptic ulcers are characterized by overhanging, punched out margins and grossly resemble ulcerated gastric CA (bx recommended due to significant bleeding of ulcers warranting aggressive tx). |
|
|
Term
| what are the normal defensive forces in the stomach? |
|
Definition
| surface mucus secretion, bicarb secretion into the mucus, *mucosal blood flow (mucosal cells are very sensitive to ischemia - constantly replicating)*, apical surface membrane transport, epithelial regenerative capacity, and elaboration of prostaglandins |
|
|
Term
| what are normal damaging forces in the stomach? |
|
Definition
| gastric acidity and peptic enzymes |
|
|
Term
| what are agents of increased damage in the stomach? |
|
Definition
| H. pylori, NSAID, ASA, cigarettes, alcohol, gastric hyperacidity, and duoenal-gastric reflux |
|
|
Term
| what are examples of impaired defenses in the stomach? |
|
Definition
| ischemia, shock, and delayed gastric emptying |
|
|
Term
| what characterizes peptic ulceration histologically? |
|
Definition
| necrotic debris, nonspecific acute inflammation, granulation tissue and fibrosis. the deeper the lesion - the more problematic, b/c the greater the chance the submucosa will be exposed to acid |
|
|
Term
| what is the worst case scenario with gastric peptic ulcers? |
|
Definition
| perforation of the gastric mucosa - leading to bleeding/flooding of gastric material (bacteria/acid) into the peritoneum |
|
|
Term
| what are the microscopic features of peptic ulcer disease? |
|
Definition
| in both gastric and duodenal ulcers: fibrinopurulent exudate, areas of necrosis, granulation tissue, and fibrosis/chronic inflammation at base. in duodenal ulcers: possible increase in brunner glands |
|
|
Term
| what are complications of peptic ulcer disease? |
|
Definition
| hemorrhage - common and can cause iron deficiency anemia/occult blood in stools, potentially lethal. perforation - may be associated with sepsis, pneumoperitoneum and death (death more likely w/gastric perforation). obstruction - possible edema/scar tissue formation esp around the pylorus. malignant transformation - uncommon w/duodenal ulcers, but documented w/gastric ulcers. |
|
|
Term
| what are clinical symptoms of peptic ulcer disease? |
|
Definition
| epigastric pain occuring w/in several hours of eating, often relieved by eating. see complications previously metioned |
|
|
Term
| what are some of the ways that helicobacter pylori contributes to gastric peptic ulcer disease? |
|
Definition
| H. pylori produce *inflammatory cells that secrete cytokines (IL 1,6,8 and TNF) which *stimulate gastrin and suppress somatostatin secretion. *IL and *histamine metabolites from H. pylori may *increase basal gastric acid secretion. H. pylori may also block inhibitory signals from the antrum to G cells/parietal cell region - causing increased gastrin release/impaired inhibition of gastric acid secretion. (net effect - more gastric acid) |
|
|
Term
| what characterizes H. pylori? who is it seen in? how is it transmitted? does it increase CA risk? |
|
Definition
| H. pylori are spiral shaped bacilli w/flagella (motile in viscous mucus), of which humans are the only hosts. it is seen in most pts with duodenal ulcers, gastric ulcers, and chronic gastritis. transmission may be oral-oral, fecal-oral, or environmental. H. pylori infection increases risk of *gastric intestinal type adenocarcinoma* and peptic ulcers |
|
|
Term
| what is the most common cause of chronic gastritis? |
|
Definition
| H. pylori - usually an antral gastritis w/high acid production |
|
|
Term
| can H. pylori invade the mucosa? |
|
Definition
| yes, but this is uncommon - it usually damages the mucosa by the substances it produces |
|
|
Term
| *how does the urease produced by H. pylori increase its pathogenicity? |
|
Definition
| urease generates ammonium from urea, elevating the pH |
|
|
Term
| *how do the adhesins produced by H. pylori increase its pathogenicity? |
|
Definition
| these allow the bacteria to adhere to mucosal cells |
|
|
Term
| *what toxins produced by some H. pylori increase its pathogenicity? |
|
Definition
| *cytotoxin-associated gene A (CagA) and a series of associated genes called *Cag pathogenicity islands promote inflammation and tissue damage |
|
|
Term
| *how does vacuolating toxin (VacA) produced by H. pylori increase its pathogenicity? |
|
Definition
| VacA causes direct cell injury |
|
|
Term
| if H. pylori is found only in he gastric mucosa, how can it still affect the duodenum? |
|
Definition
| via cytokine and toxin production |
|
|
Term
| where in the stomach is H. pylori usually not found? |
|
Definition
| in oxyntic or acid producing mucosa |
|
|
Term
| what is the morphology of mucosa infected with H. pylori? |
|
Definition
| erythematous w/a coarse or nodular appearance |
|
|
Term
| how does gastric mucosa infected with H. pylori appear histologically? |
|
Definition
| inflammation includes *neutrophils and plasma cells w/in the *lamina propria, including some intraepithelial locations. neutrophils may invade the lumen of gastric pits - causing *pit abscesses. lymphoid aggregates may form and induce *mucosa-associated lymphoid tissue (MALT) which can then transform into a lymphoma* |
|
|
Term
| what are some uncommon forms of gastritis? |
|
Definition
| reactive gastropathy, eosinophilc gastritis, lymphocytic gastritis, and granulomatous gastritis |
|
|
Term
| how can H. pylori infections be diagnosed? |
|
Definition
| serologic test for H. pylori antibodies, urea breath test (based on generation of ammonia by bacterial urease), and gastric bx |
|
|
Term
| what is reactive gastropathy? |
|
Definition
| foveolar hyperplasia (fovelar cells are mucus-producing cells), glandular regenerative changes and mucosal edema |
|
|
Term
| what are the causes of reactive gastropathy? |
|
Definition
| chemical injury, NSAIDs, bile reflux, gastric surgeries that bypass the pylorus, and GAVE (gastric antral vascular ectasia due to antral trauma characterized by edematous erythematous mucosa alternating w/less severely injured mucosa) |
|
|
Term
| how does reactive gastropathy appear microscopically? |
|
Definition
| the antral mucosa shows reactive gastropathy w/dilated capillaries w/fibrin thrombi |
|
|
Term
| what characterizes eosinophilic gastritis? |
|
Definition
| dense infiltrates of eosinophils in the mucosa and muscularis, usually in the antral or pyloric region. eosinophilic gastritis also features peripheral eosinophilia and increased IgE levels |
|
|
Term
| what typically causes eosinophilic gastritis? |
|
Definition
| allergic reactions, collagen vascular diseases: systemic sclerosis/polymyositis, parasitic infections, and *H. pylori infection |
|
|
Term
| what is lymphocytic gastritis? how does it present grossly/microscopically? who does it affect and how do they commonly present? |
|
Definition
| a condition characterized grossly by thickened folds covered with small nodules w/central aphthous ulcers affecting the entire stomach. microscopically there is a marked increase in intraepithelial T lymphocytes. pts present with abdominal pain, anorexia, nausea, and vomiting. it more commonly affects women and may/may not be associated with celiac disease. |
|
|
Term
| what is granulomatous gastritis? what diseases is it associated with? |
|
Definition
| any gastritis that contains granulomas or aggregates of tissue macrophages. it is associated with chrohn disease, sarcoid, mycobacteria, fungi, CMV, and H. pylori |
|
|
Term
| what is hypertrophic gastritis? what characterizes it? what diseases is it linked to? |
|
Definition
| generally uncommon, hypertrophic gastropathies are characterized by enlargement of rugal folds from epithelial *hyperplasia w/out inflammation* it is linked to excessive growth factor release, zollinger-ellison syndrome and menetrier disease |
|
|
Term
| what is menetrier disease? |
|
Definition
| a relatively rare disease caused by excessive secretion of *transforming growth factor alpha* that results in diffuse hyperplasia of the *foveolar epithelium of the body and fundus due to *protein losing enteropathy*. the antrum is usually spared |
|
|
Term
| how do pts with menetrier disease present? what is the microscopic appearance? is there a correlation with CA? H. pylori? |
|
Definition
| weight loss, diarrhea, and peripheral edema (due to protein loss). microscopically there is modest inflammation and glands have a corkscrew appearance with cystic dilation. there is hyperplasia of the *surface foveolar cells that do not secrete HCl, resulting in *hypochlorhydria. there is commonly patchy glandular atrophy w/hypoplasia of parietal and chief cells and risk of gastric CA is increased in adults. there is also an association with H. pylori. |
|
|
Term
| what is zollinger-ellison syndrome? |
|
Definition
| zollinger-ellison syndrome is caused by *gastrin secreting tumors* and is usually found in the *small intestine and *pancreas. the gastrinomas are slow-growing by *60-90% are malignant. the tumors may be sporadic or associated with MEN I |
|
|
Term
| how do pts with zollinger-ellison syndrome present? how does it appear microscopically? |
|
Definition
| pts present with duodenal ulcers or chronic diarrhea. microscopically: *5x increase in parietal cells w/associated thickening of the gastric mucosa. |
|
|
Term
| what is the result of the excess gastrin produced in zollinger-ellison syndrome? |
|
Definition
| *hyperchlorhydria along with hyperplasia of the mucous neck cells, mucin hyperproduction and proliferation of endocrine cells - which may form dysplastic nodules or carcinoid tumors |
|
|
Term
| what are hyperplastic polyps? |
|
Definition
| these common (benign) gastric polyps measure .5-1.5 cm in diameter, may be single, multiple, pedunculated (on a stem) or sessile (flush) and the *surface epithelium may be eroded - leading to blood loss and iron deficiency anemia |
|
|
Term
| what conditions might cause hyperplastic polyps? what do they represent? how do they appear microscopically? |
|
Definition
| autoimmune atrophic gastritis and H. pylori - hyperplastic polyps represent a response to injury and a small % may harbor areas of dysplasia. microscopically, these polyps contain *elongated, branched crypts lined by foveolar epithelium |
|
|
Term
| what are adenomatous polyps? where are they found? are they associated with any syndromes? how do they appear? |
|
Definition
| adenomatous polyps are neoplasms found mostly in the *antrum, usually <2 cm in diameter, they occur sporadically and in association with FAP (familial adenomatous polyposis). they are usually solitary w/a velvet, lobulated appearance. |
|
|
Term
| how do adenomatous polyps appear microscopically? |
|
Definition
| they are pedunduated or sessile, may be tubular/villous or a combination, cells lining the glands may be dysplastic - these polyps have a malignant potential which increases with size+number and FAP hx. |
|
|
Term
| what are fundic gland polyps? what is their appearance? are they malignant? is there any association w/their formation and drug adminstration? |
|
Definition
| smooth, glassy, sessile, circumscribed elevations in the oxyntic mucosa. fundic gland polyps are composed of *dilated glands lined by parietal and chief cells - exhibiting mucus cell metaplasia. they are benign and associated with PPIs. histologically, they appear as "swiss cheese" |
|
|
Term
| what things in pts diets may lead to malignant gastric tumors? |
|
Definition
| starches, nitrosamines, smoked and pickled foods |
|
|
Term
| are there any genetic predispositions that can lead to a higher incidence of malignant gastric tumors? |
|
Definition
| lynch syndrome/HNPCC or hereditary nonpolyposis colorectal carcinoma |
|
|
Term
| do malignant gastric carcinomas happen more often at a certain age/geographic location? |
|
Definition
| occurrences hit a sharp peak @ around age 50, with higher incidences in japan and chile (suspected due to diet) |
|
|
Term
| are there any conditions that can predispose pts to malignant gastric tumors? |
|
Definition
| H. pylori infections in pts w/gastric ulcers, adenomatous polyps, and gastritis |
|
|
Term
| what are the two types of gastric carcinoma? |
|
Definition
|
|
Term
| where are most gastric carcinomas located? |
|
Definition
| the distal stomach, along the lesser curvature of the antrum and the prepyloric area |
|
|
Term
| when are most gastric CA detected? |
|
Definition
|
|
Term
| what defines the polypoid type of gastric CA? |
|
Definition
| a solid mass projects *into the lumen and its surface may be ulcerated - which can be good if the blood is detectable - alerting the pt/dr |
|
|
Term
| what defines the ulcerating type of gastric carcinoma? |
|
Definition
| these are shallow ulcers of varied sizes, and their lateral margins are irregular and the bases are ragged (as compared to the "punched out" appearance of benign ulcers). they grow downward (mimics peptic ulcers). |
|
|
Term
| what defines the diffuse adenocarcinoma type of gastric carcinoma? |
|
Definition
| there is no true mass present, however the walls of the stomach are markedly thickened - referred to as the *linitis plastica* (leathery bottom) w/malignant cells inducing fibrosis. this results in reduced appetite and early satiety. microscopically, *signet ring cells are found |
|
|
Term
| what are some of the microscopic features of a gastric carcinoma? |
|
Definition
| they can be well differentiated to poorly differentiated. the cells may be in nests or cords. the *diffuse type of adenocarcinoma produces *signet ring cells*, which are cells filled w/mucin, which pushes the nuclei to the periphery. |
|
|
Term
| what characterizes early gastric cancer? |
|
Definition
| the tumor is limited to the mucosa or submucosa -> the name is based on the depth of invasion, it *does not refer to the duration of disease, size, metastasis, or curability. |
|
|
Term
| what % of early gastric cancer has metastasized at the time of dx? |
|
Definition
|
|
Term
| how is early gastric cancer classified? |
|
Definition
type 1 – protrudes into the lumen
type 2 – appears superficial or flat; it may be slightly elevated/depressed
type 3 – involves an excavated ulceration of type 1 or 2 tumors (more likely to be poorly differentiated) |
|
|
Term
| is early gastric cancer always a precursor to advanced? what is its potential for invasion? how does metastasis occur? |
|
Definition
| early gastric cancer is not always a precursor to advanced CA and has a lower potential for invasion. early gastric cancer often metastasizes via lymphatics to regional lymph nodes such as *virchow's node (nonpainful enlarged supraclavicular lymph node) or a krukenberg tumor (gastric tumor spreads to an ovary w/a pronounced desmoplastic/fibrotic reaction) |
|
|
Term
| what are some of the clinical features of gastric CA? |
|
Definition
| metastasis usually evident at the time of presentation, weight loss, anorexia, abdominal and back pain, chronic bleeding, anemia, melana, gastric outlet obstruction, dysphagia, and often assymptomatic esp in early gastric CA. |
|
|
Term
| what is the issue with gastric tumor that are flat/depressed? |
|
Definition
| these are hard to pick up on endoscopy |
|
|
Term
| what is another name for neuroendocrine tumors? where do they arise from? |
|
Definition
| neuroendocrine tumors AKA carcinoids or well differentiated neuroendocrine carcinomas arise from *endocrine cells in gastric mucosa. |
|
|
Term
| what other conditions might neuroendocrine tumors be associated with? |
|
Definition
| neuroendocrine cells may be associated with *endocrine cell hyperplasia, *chronic atrophic gastritis, and *zollinger-ellison syndrome. |
|
|
Term
| what might neuroendocrine tumors give rise to? do they often metastasize? |
|
Definition
| neuroendocrine cells may give rise to *carcinoid syndrome and larger tumors are most likely to metastasize. (carcinoid mnemonic = C: cardiac fibrotic lesions, valve related on the R side. A: asthma-like wheezing. R: rashes, redness and flushing. C: cramps and diarrhea) |
|
|
Term
| how can autoimmune gastritis result in neuroendocrine tumors/carcinoids? |
|
Definition
| autoimmune gastritis may result in hypergastrinemia and cause carcinoids |
|
|
Term
| how do neuroendocrine tumors/carcinoid cells appear morphologically? |
|
Definition
| yellow-tan, firm (due to a prominent desmoplastic reaction), and button-like |
|
|
Term
| how do neuroendocrine tumors/carcinoid cells appear histologically? |
|
Definition
| they have islands, trabeculae, sheets and glands. the *cells are uniform, with a scant pink granular cytoplasm and a round/oval stippled nucleus. there is minimal pleomorphism, some mitotic activity and necrosis may be present. |
|
|
Term
| what do neuroendocrine tumors/carcinoid cells stain positive for? |
|
Definition
| *synaptophysin and chromogranin A*. this is a good way to differentiate them from glandular lesions. |
|
|
Term
| what determines the symptoms experienced by pts with neuroendocrine tumors/carcinoids? |
|
Definition
| the type of hormone produced by the tumor. gastrin producing tumors may cause *zollinger-ellison syndrome. *ileal tumors produce carcinoid syndrome (cutaneous flushing, sweating, bronchospasm, abdominal pain, diarrhea, and R-sided cardiac valvular fibrosis) |
|
|
Term
| how does carcinoid syndrome happen? |
|
Definition
| tumors secrete hormones into the nonportal venous circulation and is strongly associated with metastatic carcinoma |
|
|
Term
| when is the peak incidence of neuroendocrine tumors/carcinoids? what determines their prognosis? |
|
Definition
| 6th decade. location determines prognosis |
|
|
Term
| what is the prognosis for foregut neuroendocrine tumors? |
|
Definition
| carcinoid tumors in the esophagus, stomach, and duodenum rarely metastasize and are generally cured by resection. |
|
|
Term
| what is the prognosis for midgut neuroendocrine tumors? |
|
Definition
| neuroendocrine tumors in the jejunum and ileum are often multiple and aggressive |
|
|
Term
| what is the prognosis for hindgut neuroendocrine tumors? |
|
Definition
| hindgut carcinoid tumors that arise in the appendix and colorectum are usually discovered incidentally, are rarely more than 2 cm in diameter and are almost always benign |
|
|
Term
| what other kind of CA do gastric lymphomas clinically and radiologically mimic? |
|
Definition
|
|
Term
| what are clinical symptoms of a pt with gastric lymphoma? |
|
Definition
| weight loss, dyspepsia, and abdominal pain |
|
|
Term
| how do gastric lymphomas appear morphologically? |
|
Definition
| polypoid, ulcerating or diffuse |
|
|
Term
| what type of tumor are most gastric lymphomas? |
|
Definition
| most gastric lymphomas are indolent *extra-nodal marginal zone B-cell lymphoma*, also known as mucosa-associated lymphoid tissue (MALToma), which may progress to more aggressive tumors |
|
|
Term
| what setting do gastric lymphomas arise in? |
|
Definition
| H. pylori gastritis and lymphoid hyperplasia |
|
|
Term
| what genetic mutations are associated with gastric lymphomas? what is the effect of these translocations? |
|
Definition
| t(11:18)(q21;q21), t(14:18)(q32;q21), t(1:14)(p22;q32). all of these translocations have the same effect: activation of the NF-kappaB transcription factor that promotes B cell growth |
|
|
Term
| how do gastric lymphomas/MALTomas appear histologically? |
|
Definition
| MALTomas have a *dense lymphocytic infiltrate in the lamina propria. the cells may accumulate large amounts of *pale cytoplasm called monocytoid change (may look more like a monocyte) and *express B cell markers CD19 and CD20 |
|
|
Term
| what are the gastric smooth muscle tumors? |
|
Definition
| leiomyoma (benign tumor of smooth muscle), leimyosarcoma (more aggressive malignant version), and leiomyoblastoma |
|
|
Term
| what characterizes gastric leiomyomas? |
|
Definition
| gastric leiomyomas are small, often multiple and may ulcerate the mucosa even though they are benign. they may have bizarre appearing cells. |
|
|
Term
| how do gastric leiomyomas appear histologically? |
|
Definition
| as whorls of smooth muscle cells with few mitotic figures |
|
|
Term
| how do gastric leiomyosarcomas appear histologically? |
|
Definition
| gastric leiomyosarcomas have more mitotic figures as compared to gastric leiomyomas. gastric leiomyosarcomas also have more mitotic figures, necrosis, hemorrhage (fragile stage of angiogenesis), and are often poorly differentiated. |
|
|
Term
| where do gastric leiomyosarcomas metastasize to? |
|
Definition
|
|
Term
| how do gastric leiomyoblastomas appear histologically? are they malignant? |
|
Definition
| gastric leiomyoblastomas, which are relatively rare, have *round cells w/central nuclei & an abundance of *clear cytoplasm. most are benign, but the malignant type is often seen in the *posterior wall of the stomach (characterized by the high rate of mitosis) |
|
|
Term
| where do gastointestinal stromal tumors arise from? |
|
Definition
| *gastrointestinal stromal tumors arise from the interstitial cells of cajal in the muscularis propria* (know this) |
|
|
Term
| what % of gastrointestinal stromal tumors make up gastric CA? |
|
Definition
|
|
Term
| what is the most common mesenchymal tumor of the abdomen? |
|
Definition
| gastrointestinal stromal tumors (GISTs) |
|
|
Term
| are gastrointestinal stromal tumors (GISTs) palpable? malignant? |
|
Definition
| gastrointestinal stromal tumors may be palpable and can be benign or malignant. the larger ones tend to be malignant. |
|
|
Term
| who are gastrointestinal stromal tumors (GISTs) more common in? |
|
Definition
|
|
Term
| if gastrointestinal stromal tumors (GIST) are uncommon in children, what is one incidence where they are found in kids? |
|
Definition
| if gastrointestinal stromal tumors are found in children, it is likely to be in a young female with "carney's triad": gastric GIST, paraganglioma and pulmonary chondroma. |
|
|
Term
| what condition increases incidence of GIST? |
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Definition
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Term
| what is a genetic mutation commonly found in pts with GIST? (*know this*) |
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Definition
| 75-80% of gastrointestinal stromal tumors have an oncogenic gain of function mutation in the gene encoding the *tyrosine kinase c-KIT, which is the receptor for stem cell factor |
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Term
| what kind of cell do GISTs share a common stem cell with? |
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Definition
| interstitial cells of cajal (pacemaker cells for gut peristalsis) which also express c-KIT (CD117)and CD34 |
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Term
| how do GISTs promote tumor cell proliferation/survival? |
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Definition
| active c-KIT and PDGFRA (platelet derived growth factor receptor alpha) receptor kinases produce intracellular signals that activate the RAS and P13K/AKT pathways -> promote tumor cell proliferation and survival |
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Term
| what does a greater number of mitosis in GISTs imply? |
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Definition
| a higher level of malignancy |
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Term
| how do GISTs appear morphologically? |
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Definition
| primary GISTs may be large. they are usually solitary, well circumscribed fleshy masses and the overlying mucosa may be intact or ulcerated |
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Term
| how do GISTs appear histologically? |
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Definition
| the cells may be spindle cells or epitheliod type cells. |
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Term
| where do GISTs metastasize to? |
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Definition
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Term
| what happens if a GISTs mucosa ulcerates? |
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Definition
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Term
| what are symptoms from GISTs related to? |
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Definition
| mass effects (early satiety) |
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Term
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Definition
| surgical resection or medication that inhibits the c-KIT signal transduction pathway |
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Term
| what can a GIST appear as unless cytologic studies are performed? |
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Definition
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Term
| what is a gastric xanthoma? how do they appear? where are they found? |
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Definition
| a yellow nodule/plaque < 3 cm that barely protrudes from the surrounding mucosa. gastric xanthomas rarely attain the size and shape of a polyp and are often found near sites of mucosal repair, *adenocarcinomas*, or along the lesser curvature, antrum, and prepyloric areas. |
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Term
| what are gastric xanthomas associated with? |
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Definition
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Term
| what do gastric xanthomas consist of? |
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Definition
| lipid laden macrophages containing cholesterol and neutral fat embedded in the lamina propria. |
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Term
| are gastric xanthomas associated with hypercholesterolemia? |
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Definition
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Term
| what are inflammatory fibroid polyps? what do they consist of? how do they appear? where are they found? |
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Definition
| these polyps consist of submucosal proliferations of spindle cells and small vessels w/inflammatory infiltrate w/many eosinophils. 80% are found in the antropyloric region and they may be firm, sessile or pedunculated. they may be ulcerated and they make up < 1% of all gastric polyps, |
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Term
| what is a pancreatic heterotopia? |
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Definition
| this may present as a polyp consisting of small *submucosal nodules of pancreatic tissue at the cardioesophageal junction OR they may also present as a *submucosal lesion in the antral and prepyloric regions. (part of the pancreas may be out of place, commonly in the stomach, forming a polyp) |
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Term
| what are phytobezoars? how are they treated? |
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Definition
| accumulations of vegetable products in the stomach. they may be associated with swallowing gum and can cause delayed gastric emptying (as seen in neuropathy of diabetes/gastric CA). they are best treated w/partial gastrectomies and cellulase. |
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Term
| what is a trichobezoar? who are they seen in? |
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Definition
| a hairball with a gellatinous matrix, which can produce a complete cast of the stomach. they are seen in people w/long hair who nervously eat it. |
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