Two cases of gastric carcinoids: Diagnostic and therapeutic aspects

Abstract

Two cases of gastric carcinoid tumors with the foregut carcinoid syndrome are presented. Due to elevated urinary levels of 5-hydroxyindoleacetic acid (5-HIAA), primary tumors of midgut origin were suspected. Provocation with pentagastrin (PG) elicited atypical flushing and severe hronchoconstriction, most probably caused by the release of histamine. Excessive excretion of the main histamine metabolite, tele-methylimid-az01e acetic acid (MeImAA), in urine of both patients was demonstrated. Both patients had good symptomatic relief with prednisolone and blockade of histamine receptors. One of the patients had excessive secretion of serotonin (5-HT) as well as of histamine. Peripheral blockade of 5-HT2receptors was therefore added to the medical treatment. This patient had a subjective and biochemical response to cytotoxic treatment with streptozutocin and later responded well to a somatostatin analogue.On clinical suspicion of a foregut carcinoid tumor, or in patients with carcinoid tumors without anatomical localization, PG provocation should not be used until the excretion of MeImAA has been determined.

Vesicular monoamine transporter 2 as a marker of gastric enterochromaffin-like cell tumors

“…Extensive and intense VMAT2 immunoreactivity was detected in all clinicopathological subtypes of well-differentiated ECL cell tumors. These include sporadic type-III cases, usually not associated with hypergastrinemia and sometimes showing clinical evidence of histamine production [1,18], as well as those associated with hypergastrinemia, either due to diffuse chronic atrophic gastritis of the corpus-fundus mucosa (type-I cases) or to combined MEN/ZES (type-II cases), usually lacking signs of histamine hypersecretion and the histamine syndrome [2,3,8,20,27]. In addition, most cells forming the hyperplastic-dysplastic growths associated with type-I and type-II ECL cell tumors were intensely VMAT2 positive.…”

Morphological, molecular, and prognostic aspects of gastric endocrine tumors

“…The possibility of neoplastic progression from well-differentiated ECL cell tumor, especially of type III sporadic group, to PDEC cannot be ruled out although it seems to be a rare event on the basis of the presently available histopathological and follow-up studies. This possibility is suggested by the observation of a few cases with coexisting well-and poorly differentiated endocrine growths and the reported "atypical," G2 sporadic carcinoids (Ahlman et al, 1988;Bordi et al, 1997;Rindi et al, 1993Rindi et al, , 1999aSweeney and McDonnell, 1980).…”

Day-to-day variation in urinary excretion of the histamine metabolite methylimidazoleacetic acid

“…2. Evaluation of bronchial or gastric carcinoid patients before testing with pentagastrin [5], or as a tumour marker at follow-up after treatment [6]. 3.…”