The Carcinoid Tumours:

El Awady Sayed Ahmed Daoud

The carcinoids are relatively rare tumours whichhave been described as the ”missing link” betweenbenign and malignant tumours. They were first describedby Lubarsch in 1888. The term ”karzionoid” wasintroduced by Oberndorfer (1907) in an effort to stressthe benign nature of the tumour with a morphologicappearance of carcinoma. The carcinoid cell is nearlyubiquitous. It is of neuroectodennal origin and it ispredictably found in tissues derived from endoderm.The carcinoid tumours arise wherever the carcinoidcell is found. They were reported in all portions ofthe gastrointestinal tract, most commonly in the appendixand ileum. Extragastrointestinally, they arecommon Ly found in the bronchial tree.The carcinoid is characteristically a small firmsubmucosal tumour, commonly ranging from 4 mm to 3.5cmin diameter. It is yellow, grey, or grey white incolour. It has a slow rate of growth and may be multiple.There are five generally accepted carcinoidhistologic growth patterns, these are the insular, thetrabecular, the glandular, the undefferentiated, andthe mixed types. The tumour may secrete multipleamine and polypeptide hormones, the most important ofwhich is serotonin.Carcinoids with metastases as well as those directlydraining into the systemic circulation may presentwith the carcinoid syndrome. This syndrome consists ofcutaneous flushing, diarrboea, and asthma, which occurin episodes triggered by known or unknown stimuli. Symptomsof the primary tumour are often nonspecific, usuallyin the form of nauaia, abdominal pain, vomiting,intermittent obstruction, and haemoptysis.Diagnostic delay is common, thus giving a chancefor metastases. Diagnosis of the primary tumour dependson biopsy and histopathologic examination, roentgenic findingsand endoscopy. For suspected liver metastases, computedtomography, liver scan and ultrasonography are resortedto. The urinary 5-hydroxyindoleactic acid excretionis the most useful single test in diagnosing thecarcinoid syndrome.Surgical excision is the treatment of choice.Hepatic resection of accessible lesions should be considered.In patients with unresectable. metastatic.or recurrent carcinoid after resection. two approacheshave been used. These are:1- Antihormonal measures to ameliorate the symptoms ofthe carcinoid syndrome.2- Cytotoxic chemotherapy aimed at destroying thetumour.Radiation therapy is ineffective, although forextensive liver metastases some palliation has beclaimed.Prognosis for the patient with treated carcinoidtumour is very favourable if the staging shows thatthe tumour was localized.at the primary site.