Carcinoid of the vermiform appendix. Description of three clinical cases and review of the literature.

Carcinoids of the appendix represent a separate class of tumours with characteristics that vary between benign (adenomas) and malignant (carcinomas) neoplasias. A recent nomenclature identifies them as diffuse neuroendocrine system (DNS) and/or, parallely, as neuroendocrine tumours (NET): the gastroenteric tract is the site of about 64.3% of carcinoids, followed by the respiratory tract with 25.3%. Among the gastrointestinals, tumour of the small intestine is the one with the highest incidence with 28.5%, followed by the appendix with 4.77%, the rectum with 13.6% and the stomach with 4.6%. Carcinoid of the colon has an incidence of 8.62%, with the caecum which alone represents 34.5% of colic localisations. The 3 cases described are an example of the behavioural unpredictability of intestinal carcinoids. The first case is that of a female patient in whom the primary tumour was only discovered after liver metastasis was documented. The second case regards a girl who, at admission, presented a picture of acute abdomen with the symptomatological characteristics of acute appendicitis. She was submitted to an appendicectomy. Subsequent investigations carried out in the postoperative period documented the presence of liver metastasis at the V and VI liver segments. The last case, similar to the second from certain points of view, shows the need to carry out a right hemicolectomy with removal of locoregional lymphnodes in the event of an appendicular carcinoid >2 cm. Both laboratory and instrumental examinations contribute to the diagnosis of intestinal carcinoid. The main laboratory examinations are based on the measurement of serotonin and urinary 5-hydroxy-indolacetic acid. First level instrumental examinations for the diagnosis of intestinal carcinoid are represented by CT with and without contrast medium, diagnostic endoscopy and, to better highlight the presence of locoregional metastases, scintigraphy with octreotide and PET. An alternative treatment of liver metastases other than surgery is most certainly chemoembolisation. This latter treatment has also proved very effective as a neoadjuvant treatment for liver metastases before subjecting the patient to liver resection. Treatment with somatostatin, on the other hand, proved effective in controlling tumour secretion, so attenuating the inconveniences of carcinoid syndrome.