Diagnostic criteria of classical carcinoids

Expression of the Intestinal Transcription Factor CDX2 in Carcinoid Tumors Is a Marker of Midgut Origin

Context.—Carcinoid tumors are classified according to their site of origin into foregut, midgut, or hindgut carcinoids, which have different presentations and prognosis. The intestinal transcription factor CDX2 has been found to be expressed in most intestinal adenocarcinomas but in less than one half of the gastrointestinal carcinoids according to 1 study.

Objective.—To determine whether CDX2 expression in carcinoid tumors varies by the site of origin and whether CDX2 expression is retained in metastatic disease.

Design.—Sections of formalin-fixed and paraffin-embedded tissue from 36 primary carcinoid tumors and 5 cases of metastatic carcinoid to the liver were immunohistochemically stained for CDX2. The percent of cells with nuclear immunoreactivity and the intensity of staining were assessed.

Results.—All 18 foregut carcinoids (10 pulmonary and 8 gastric) were negative (0%) for CDX2. All 11 midgut carcinoids (100%) were positive for CDX2 with moderate to strong staining in more than 50% of the cells. Only 2 (29%) of 7 of hindgut carcinoids were CDX2-positive with the 2 positive cases showing weak to moderate staining intensity in less than 10% of the cells. Expression of CDX2 in more than 50% of tumor cells was seen only in midgut carcinoids (P < .001). CDX2 expression in metastatic tumors was consistent with the site of origin.

Conclusions.—Midgut carcinoid tumors and their metastases are distinct from foregut and hindgut carcinoids in that they express high levels of CDX2. Additional studies are needed to determine whether CDX2 immunostaining may be helpful in determining the primary site of metastatic carcinoid tumors of unknown origin.

Carcinoid heart disease: an update

BACKGROUND

Carcinoid tumours are a poorly defined collection of lesions, histopathologically indistinguishable from gastroentero-pancreatic neuroendocrine tumours. In this report, we discuss epidemiology and survival, clinical presentation, carcinoid valvular heart disease (CVHD), histopathological considerations and treatment options.

METHODS

Review and update of the literature.

RESULTS

The term carcinoid suggests a disease entity, but with increasing knowledge it becomes progressively confusing. To avoid further confusion, it is advisable to define these tumours using differentiation, stage, primary site, known tumour products and an associated clinical syndrome. Incidence varies between 0.8 and 1.9/100,000 population. About 20% present with metastases, with a 5-year survival varying between 15% and 35%. Metastatic disease frequently accompanies the carcinoid syndrome (flushing, diarrhoea, wheezing and CVHD). CVHD incidence is about 50%, and seems unrelated to disease duration and tumour mass. An aetiological relation of CVHD with urinary 5-HIAA remains to be confirmed. Resection is the only curative option. Surgery can also offer prolonged palliation and is needed to restore bowel transit in obstructive/ischaemic bowel problems. Adequate palliation of hormone-related symptoms can also be achieved by somatostatin analogues, meta-iodo-benzyl-guanidine preparations and interferon-alpha formulations, all with a 70% response rate. Embolization of liver metastases has led to objective responses in about 50% of patients, but is accompanied by significant side effects.

CONCLUSIONS

Most patients are cured by surgery. Symptom relief is the main target in metastatic disease and can be achieved by a range of equally potent biologically active medications, debulking surgery and hepatic embolization.

Midgut Carcinoids and Solid Carcinomas of the Intestine: Differences in Endocrine Markers and p53 Mutations

Fifteen midgut carcinoid tumors and 5 solid carcinomas of the intestine with carcinoid-like morphological features were evaluated histochemically and immunohistochemically with respect to various endocrine markers and expression of mutant p53 protein. Direct sequencing of the p53 gene after PCR amplification was carried out on microdissected cells from all tumors. All investigated carcinoid tumors showed chromogranin and argentaffin reaction, but lacked nuclear immunostaining with p53 antibodies. In 14 immunohistochemically negative midgut carcinoid tumors, no mutations were identified. One carcinoid tumor devoid of p53 staining was, however, found to contain mutation in exon 6 of the p53 gene. In contrast, the solid carcinomas were essentially chromogranin negative but all displayed clearly positive p53 staining in a variable number of cell nuclei. Sequence analysis of exons 5-8 of the p53 gene in the 5 carcinomas showed mutations in exons 6 and 7 in 2 tumors and in exon 8 in 2 other tumors, while no mutation was detected in the fifth tumor. The carcinoid tumors and the solid carcinomas of the small intestine are thought to derive histogenetically from endocrine cells and enterocytes, respectively. The present results substantiate that divergent mechanisms operate in the development of the two tumor types.

Interferon treatment of neuroendocrine tumour xenografts as monitored by MRI

The neuroendocrine-differentiated colonic carcinoma cell line (LCC-18) was transplanted to 29 nude mice (Balb/c). The purpose of the present study was to establish an animal model that would allow monitoring with magnetic resonance imaging (MRI) of changes induced by interferon (IFN) therapy and to evaluate whether the therapeutic response, as expressed by changes in MR signal characteristics and tumour proliferation activity, could be modulated by different IFN dosages. IFN did not seem to have any obvious antiproliferative effect on the LCC-18 tumour cell line transplanted to nude mice and no convincing treatment-related changes in rho values or T1 and T2 relaxation values were observed. The animal model was probably unsuitable for demonstration of IFN effects.