carcinoid

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Related to Carcinoid tumors: carcinoid syndrome, Neuroendocrine tumors

carcinoid

 [kahr´sĭ-noid]
1. a yellow circumscribed tumor of the gastrointestinal tract or bronchus formed from chromaffin cells. See also carcinoid syndrome.
carcinoid syndrome a symptom complex associated with carcinoid tumors (argentaffinomas), marked by attacks of severe cyanotic flushing of the skin lasting from minutes to days and by watery diarrhea, bronchoconstrictive attacks, sudden drops in blood pressure, edema, and ascites. Symptoms are caused by serotonin, prostaglandins, and other biologically active substances secreted by the tumor.

The specific symptoms associated with this disorder depend upon the site of the primary tumor; tumors are found most commonly in the appendix and the terminal third of the ileum but can also be in the bronchi, ovaries, testes, and anywhere along the entire length of the alimentary tract. The full set of carcinoid symptoms are manifested only when the liver is involved.

Diagnosis of the condition is established by a 24-hour urine test for 5-hydroxyindoleacetic acid (5-HIAA), the end product of the breakdown of tryptophan to serotonin. Patients with carcinoid syndrome may have very high levels of 5-HIAA, 100 to 500 mg in 24 hours.

Carcinoid tumors are not always benign and should be approached as if they were malignant growths. Surgical excision of the tumor and any associated mesenteric nodes is the treatment of choice. Chemotherapy can be used with metastatic disease, and other drugs are prescribed as indicated to manage the hypotension, diarrhea, flushing, and other symptoms. Efforts are made to improve nutrition and to avoid serotonin-containing foods, such as walnuts and bananas, which are known to precipitate an attack and make accurate diagnosis difficult.

car·ci·noid tu·mor

a usually small, slow-growing neoplasm composed of islands of rounded, oxyphilic, or spindle-shaped cells of medium size, with moderately small vesicular nuclei, and covered by intact mucosa with a yellow cut surface; neoplastic cells are frequently palisaded at the periphery of the small groups, and the latter have a tendency to infiltrate surrounding tissue. Such neoplasms occur anywhere in the gastrointestinal tract (and in the lungs and other sites), with approximately 90% in the appendix and the remainder chiefly in the ileum, but also in the stomach, other parts of the small intestine, the colon, and the rectum; those of the appendix and small tumors seldom metastasize, but reported incidences of metastases from other primary sites and from tumors exceeding 2.0 cm in diameter vary from 25-75%; lymph nodes in the abdomen and the liver may be conspicuously involved, but metastases above the diaphragm are rare. About 1% of cases are associated with the carcinoid syndrome, usually after the portal circulation is bypassed as in cases involving liver metastases.
See also: carcinoid syndrome.

carcinoid

(kär′sə-noid′)
n.
A small, slow-growing, benign or malignant tumor, found usually in the gastrointestinal tract, that is composed of islands of rounded cells and secretes serotonin.

carcinoid

A well-differentiated tumour of neuroendocrine-neural crest origin, which has paracrine activity. 85% of carcinoid tumours are located in the GI tract (appendix, liver, ileum, stomach, colon, rectum),10% in the lungs and bronchi, and the rest in the breast, kidney, ovary, prostate, skin, thymus, and elsewhere.

Clinical findings
Flushing, tachycardia, facial and periorobital swelling, low blood pressure, abdominal pain, weight loss, diarrhoea.
Appendiceal carcinoids are clinically benign; liver carcinoids are usually functionally malignant, as they release large amounts of vasoactive amines (e.g., serotonin) into the circulation.

Lab
Increased serotonin, 5-HIAA in serum, urine.
 
Management
Resection

Carcinoids basic classification
Microcarcinoid Tumourlet < 0.5 cm in diameter.
Carcinoid Benign Usually measure > 0.5 cm; either invades muscularis mucosae or is macroscopically visible, but confined to mucosa or submucosa and not angioinvasive.
Borderline carcinoid Either angioinvasive, but measures < 1 cm and is confined to mucosa/submucosa or 1–2 cm, no angioinvasion and limited to the mucosa/submucosa.
Mucinous/goblet cell carcinoid Aggressive; possibly same as agyrophilic adenocarcinoma.
Atypical carcinoid Carcinoid + necrosis OR mitoses > 2/10hpf OR cytological atypia.
Malignant carcinoid Carcinoid + functional tumour OR > 1 cm + angioinvasion OR invades muscularis propria.

Note: The term neuroendocrine tumour is increasingly preferred.

Patient discussion about carcinoid

Q. what is carcinoid tumors? I had my appendix removed and the doctor came in the room very shocked and said it was full of carcinoid tumors. Im scared to get them somewhere else.

A. ya I have pain all the time but the doctors wont give me anything cuz im so young they don't want me hooked on anything. thank you sooo much for being so kind.

More discussions about carcinoid
References in periodicals archive ?
Carcinoid syndrome affects fewer than 10% of patients with carcinoid tumors. (6) Therefore, although carcinoid tumor should be suspected in patients with suggestive symptoms, other diagnoses must be considered.
Goblet cell carcinoid tumors are located between carcinoid tumors and well-differentiated adenocarcinomas in terms of prognosis (6).
Pulmonary carcinoid tumor is a rare NET that accounts for less than 2% of all lung tumors.
reported metastases in 15.9% of cases of primary testicular lesions with no distinguishing marker for carcinoid tumors [2].
Primary carcinoid tumor in a retroperitoneal mature teratoma: report of a case.
When abdominal carcinoid tumors are suspected, the preferred imaging technique is CT, which typically shows mucosal thickening, a submucosal mass, or luminal narrowing.
Takeuchi et al., "Rectal granular-cell tumor difficult to distinguish from carcinoid tumor," Digestive Endoscopy, vol.
Gastric carcinoid tumors, also called gastroenteropancreatic neuroendocrine tumors, comprise approximately 10% to 30% of all carcinoid tumors [20].
Roy, "Goblet cell carcinoid tumors of the appendix: An overview," World Journal of Gastrointestinal Oncology, vol.
DIPNECH was defined more loosely by World Health Organization as PNEC proliferation that may be confined to bronchial or bronchiolar epithelium, extraluminal proliferation in the form of tumorlets, or development of carcinoid tumors [27].
A prominent characteristic of jejunal and ileal (previously named as midgut carcinoid tumors) NENs is the secretion of serotonin (5-hydroxytyramine, 5-HT) and other amines [17, 18].