Search

There are seven published cases of ileal carcinoid tumor misdiagnosed and treated as Crohn's disease. We evaluated 176 consecutive ileal carcinoid patients to determine the frequency with which this occurs. Clinical, hormonal, and radiographic data of those patients misdiagnosed were also analyzed to determine whether there were clinical lessons to be learned.Records of 176 patients with ileal carcinoid tumors were retrospectively reviewed. It was determined whether patients were diagnosed and treated for Crohn's before the diagnosis of carcinoid was established. Radiographic, hormonal, and clinical data were reviewed and comparison was made to those who were correctly diagnosed as having carcinoid.Of 176 ileal carcinoid patients, 4 were initially diagnosed and treated as having Crohn's; their mean age was 51.5 +/- 8.9 yr. The hormonal data of patients treated as Crohn's was indistinguishable from patients with known carcinoid. Two of four patients had colonoscopy performed, neither had terminal ileal intubation. None responded to medical therapy and all required surgery for diagnosis. The mean time from symptom onset to the establishment of the correct diagnosis was 24 +/- 6.9 months with a range of 6 to 45 months.Although rare, ileal carcinoid tumors may be misdiagnosed as Crohn's disease. In our study approximately 2.3% of patients with ileal carcinoid were initially diagnosed and treated as having Crohn's disease. The presence of disease refractory to medical therapy should alert clinicians to this possibility and urinary 5-HIAA levels should be obtained as a screening test.

Our goal was to describe the abdominal CT findings in 52 patients with midgut carcinoid tumors and correlate these findings with their biochemical profiles.Abdominal/pelvic CTs of 52 patients with midgut carcinoid tumors were reviewed retrospectively for the presence of liver metastases, mesenteric and peritoneal disease, bowel changes, lymphadenopathy, and the presence of the primary tumor. Logistic regression models were used to evaluate the association between these findings and the serum and platelet serotonin and urine 5-hydroxyindolacetic acid levels.The most common finding was hepatic metastases (34/52). Nonspecific mesenteric soft tissue stranding was present in 26 of 52 and a discrete mesenteric mass was present in 25 of 52. These masses had linear, radiating soft tissue spokes in 16 of 25 and contained calcification in 10 of 25. Retroperitoneal and mesenteric lymphadenopathy was present in 14 of 52 and 11 of 52 cases, respectively. Carcinomatosis was present in 11 of 52. Bowel wall thickening was seen in 9 of 52. Six patients had a small bowel obstruction. Elevated serum serotonin, platelet serotonin, and urine 5-hydroxyindolacetic acid levels were significantly associated with the presence of liver metastases (p = 0.0032, 0.0098, and 0.0450, respectively). Elevated platelet serotonin levels were also significantly associated with the presence of a mesenteric mass (p = 0.0101).In our population, the most common findings of a midgut carcinoid tumor are liver metastases, nonspecific mesenteric soft tissue changes, a discrete mesenteric mass with radiating soft tissue spokes, often containing calcification, and lymphadenopathy. As expected, liver metastases correlate strongly with the presence of elevated biochemical levels. A new observation is the correlation of elevated platelet serotonin levels and mesenteric masses. We hypothesize that platelet serotonin may be the factor that stimulates stromal cells to produce mesenteric fibrosis and mass formation.

Six patients with the carcinoid syndrome (C.S) had serum luteinizing hormone (LH) concentrations that were greater than age and sex matched control subjects. The serum follicle stimulating hormone (FSH) and testosterone concentrations of the groups did not differ. Four of the 5 C.S. patients tested had an increase in serum testosterone after human chorionic gonadotropin administration and 5 of the 5 subjects tested had an increase in serum LH after clomiphene citrate administration. One of the 4 subjects treated with the tryptophan hydroxylase inhibitor parachlorophenylalanine (PCPA) had a reduction in serum testosterone. He was also receiving methysergide. The other 3 subjects treated with PCPA did not have any persistent alterations in serum testosterone.

To examine the role of kallikrein in the etiology of flushing in the carcinoid syndrome, chromogenic substrates specific for kallikrein were used to measure two isoenzymes of this substance. The plasma and glandular kallikrein levels were determined in 20 carcinoid patients and in 17 controls. Kallikrein levels were not significantly different between these two groups. Twelve carcinoid patients and six controls were given alcohol and the kallikrein activity was measured before and at 2, 5, and 10 minutes after alcohol ingestion; kallikrein activity did not change significantly. Kallikrein was absent from the primary tumors of seven patients with carcinoids. These studies, therefore, indicate that kallikrein with subsequent induction of bradykinin formation is not solely responsible for the flushing in the carcinoid syndrome.

To determine whether measurement of serotonin in urine would give useful complementary information to the usual measurement of 5-hydroxyindoleacetic acid (5-HIAA) in urine and platelet serotonin in platelets, I measured these analytes in 75 consecutive patients with carcinoid tumors, and found that 75% had above-normal urinary 5-HIAA excretion, 64% had above-normal serotonin excretion, and 64% had above-normal platelet serotonin concentration. Six patients had increased urinary serotonin, but 5-HIAA excretion and platelet serotonin concentration were normal. Only two of a further 50 patients with solid noncarcinoid tumors--and none of 55 patients with flushing or diarrhea, who did not prove to have a carcinoid tumor--had increased urinary serotonin. Ingestion of four bananas (a food rich in serotonin) increased urinary 5-HIAA but not urinary serotonin excretion of seven normal subjects. Evidently, measurement of urinary serotonin excretion is helpful in the evaluation of patients with suspected carcinoid tumors.

Platelet monoamine oxidase (MAO) activity and urinary excretion of 5-hydroxyindoleacetic acid (5-HIAA), serotonin, tyramine and tryptamine were measured in patients with a variety of metastatic cancers and in healthy control subjects. The patients with cancer had higher platelet MAO activity and lower urinary excretion of 5-HIAA, sertonin and tyramine than the healthy subjects. The urinary tryptamine excretion was not significantly different in the two groups. At the present time it is unclear if the alterations in platelet MAO activity and monoamine excretion are casually related.

The urinary excretion of 5-hydroxyindoleacetic acid, 5-hydroxytryptophan, serotonin, tryptamine, and tyramine and the serum serotonin concentration were determined in 38 consecutive patients with metastatic carcinoid tumors. Four of the 23 patients with the carcinoid syndrome (15%) had markedly elevated excretion of 5-hydroxytryptophan. None of the patients had markedly elevated excretion of tryptamine or tyramine; a substantial number of patients had moderately low urinary excretion of these amines. All of the patients with the carcinoid syndrome had elevated urinary 5-hydroxyindoleacetic acid excretion; 2 of these patients had normal serum serotonin concentrations, suggesting that quantitative 5-hydroxyindoleacetic acid excretion is the most reliable test for the carcinoid syndrome. Although tryptamine secretion by carcinoid tumors is rare, 5-hydroxytryptophan secretion may be more common than is recognized.

Using a highly specific radioenzymatic assay we determined the serotonin concentration in 80 types of foods. The following fruits had a high serotonin concentration (mean +/- SEM) expressed in micrograms/g weight: plantain 30.3 +/- 7.5; pineapple 17.0 +/- 5.1; banana 15.0 +/- 2.4; Kiwi fruit 5.8 +/- 0.9; plums 4.7 +/- 0.8; and tomatoes 3.2 +/- 0.6. Only nuts in the walnut or hickory family had a high serotonin concentration expressed in micrograms/g weight; butternuts 398 +/- 90; black walnuts 304 +/- 46; English walnuts 87 +/- 20; shagbark hickory nuts 143 +/- 23; mockernut hickory nuts 67 +/- 13; pecans 29 +/- 4; and sweet pignuts 25 +/- 8. Ingestion of these fruits and nuts resulted in an increase in urinary 5-hydroxyindoleacetic acid excretion with no change in platelet serotonin concentration. The above foods should not be eaten while a urine is being collected for 5-hydroxyindoleacetic acid analysis.

Plasma tryptophan (Trp) is reported to be decreased in some patients with the carcinoid syndrome. To determine if the plasma levels of other amino acids are also altered in the carcinoid syndrome, we used a fas-liquid chromatographic method to determine the plasma amino acid concentration of nine patients with the carcinoid syndrome and nine age-matched healthy control subjects. In comparison to the control subjects, the patients with the carcinoid syndrome had decreased plasma concentration of valine (Val), isoleucine (Ile), lysine (Lys), and ornithine (Orn), and an increased plasma concentration of methionine (Met). With the exception of a decrease in urinary excretion of proline (Pro) and hydroxyporline (Hyp), the patients with the carcinoid syndrome had normal quantities of amino acids in their urine. Plasma Met returned to normal when serotonin production by the tumor was reduced 60% by parachlorophenylalanine (PCPA); the other amino acid abnormalities persisted. Further studies are needed to determine the significance of these amino acid abnormalities.