Carcinoid

The term carcinoid is understood in medicine a certain variety of neuroendocrine tumors. The typical symptoms that occur in the context of carcinoid tumors, are in their entirety also called carcinoid syndrome (synonyms: Steiner - voerner syndrome or Cassidy -Scholte syndrome).

System

Carcinoid tumors are the so-called neuroendocrine system. They are characterized by their usually low malignancy, carcinoids are due to the relatively high degree of differentiation of tumor cells characterized by a slow growth and a good prognosis. However, they can also occur in a malicious, malignant variant.

Depending on the location of the Thymuskarzinoid, Bronchuskarzinoid, Appendixkarzinoid, Ileumkarzinoid, Mastdarmkarzinoid, Duodenalkarzinoid and the Magenkarzinoid be distinguished, with approximately 80 percent of the tumors are localized in the terminal ileum or appendix.

Meanwhile, the term carcinoid is rarely used, instead, is now spoken mostly of the diffuse neuroendocrine neoplasms or according to the WHO definition of neuroendocrine tumors ( NET).

Special NET forms are the GEP -NET (eg VIPomas, gastrinomas, insulinomas or pheochromocytoma ).

Pathology

Carcinoid tumors are submucosal location that may arise wherever neuroendocrine cells are present. In the course of tumor progression, the tumors invade the muscularis and in the further course of the disease first lymphatic and hematogenous metastases later. Often in the metastatic carcinoid are larger than the primary tumor.

The symptoms arise, in contrast to most neoplasms not by displacing healthy tissue or the consuming effect, but primarily through the production of tissue hormones: Kallikrein and others, but especially serotonin.

Symptoms

The carcinoid syndrome is characterized by the triad of diarrhea ( diarrhea), flushing ( blushing ) and Hedinger syndrome (cardiac manifestation of the carcinoid syndrome ).

A persistent diarrhea is often a first indication of the disease. A " flush symptoms " (or " flush syndrome " ) is a sudden blue-red discoloration of the face, neck and understand sometimes the upper body. For the diagnostic localization of the flush is relevant that he for an already metastasized ( in the liver, often palpable ) speaks or primary extra-intestinal location of the carcinoid. With only intestinal (situated within the gastrointestinal tract ) tumors, serotonin is degraded by the liver ( see also portal venous circulation) and do not lead to a flush. In the late stage, the syndrome is characterized by Endokardfibrosen the right heart, which may lead to tricuspid insufficiency and pulmonary stenosis to (both forms of heart valve damage). Other long-term consequences can be among other pellagraartige dermatoses, tachycardia ( rapid heart rate ), behavioral changes, a Cushing's symptoms ( due to ectopic ACTH - education), and possibly asthma attacks.

Diagnosis

A first indication deliver increased chromogranin A levels in serum. Leading the way is usually the detection of elevated levels of serotonin in serum or 5- Hydroxyindolylessigsäure ( degradation product of serotonin) in urine. Normal levels of serotonin or a negative detection of 5 - HIAA, however, do not rule out a tumor. The diagnosis is often made late, as carcinoids / neuroendocrine tumors often do not cause symptoms long. Non-specific symptoms that can intermittent, such as diarrhea, constipation, abdominal pain and flushing are often misdiagnosed as irritable bowel syndrome. Often the tumors are, therefore, at the time of diagnosis already advanced and may have metastasized despite their sometimes small size.

Primary tumor and metastases by ultrasonography with computed tomography ( CT), angiography or endoscopy demonstrated. It is also possible octreotide scintigraphy because the carcinoid tumor has these receptors. With newer nuclear medicine detection methods, especially with PET ( usually coupled with a CT ), is currently a strong effort to recognize the often very small tumor foci at the earliest possible stage.

Therapy

Primary treatment is surgical removal of the primary tumor and, if possible, individual metastases. The treatment with the somatostatin analogue ( octreotide ) can improve the symptoms by inhibiting hormone secretion and probably also acts cytostatic effects on the tumor. Also therapy with alpha interferon and serotonin antagonists ( methysergide ) have proven to be effective.