Pathological anatomy of carcinoid

Localization of carcinoids no significant impact on their pathological features. Tumors are always located in the submucosal layer and, as a rule, do not apply to mucous membranes, and penetrate into the muscle and, rarely, serous layers. In the Appendix are more common single knots, while in the small intestine - multiple (Fig. 46). The size of carcinoid range from 0.5 to 3 see Moertel (1961) found that tumors from 2 to 2.5 cm most commonly metastasize. In the context of the tumor is usually yellow-grey because of the high cholesterol or other lipids (Sokoloff, 1968), solid to the touch, often reaches cartilaginous consistency. Tumor borders strictly separated from the surrounding tissues, although capsule and missing. Carcinoid most often spreads to the liver, lymph nodes, abdomen, sometimes in the retroperitoneal lymph nodes.

Fig. 46. Plot ileum containing 68 primary carcinoid tumors.
The arrow indicates the greatest tumor (1.5 cm in diameter).

Very peculiar nature of heart failure with carcinoid syndrome. Some patients are morphological signs of failure tricuspid valve and pyloric stenosis pulmonary artery without manifestations of valvulitis as such.
The damaged leaf valve thicken, are shortened, become dense and rigid. The free edge of the valves thickens; chordae tendineae usually shortened, correctly located, papillary muscles are lengthened, flattened and stretched. The function of valves are disrupted, there is a regurgitation of blood in the ventricle. Muscle of the right ventricle usually gipertrofirovannyj, swollen.
Microscopic examination revealed that the carcinoid consists of homogeneous round or polygonal epithelial cells of the small sizes, with moderate amount of protoplasm with argentophile granules and centrally located kernel spherical shape. Usually the cells are connected in a cell (alveoli)in the center of which often is homogeneous, eosinophilic substance.
The alveoli sometimes give the carcinoid pseudohistory (Fig. 47).

Fig. 47. Carcinoid rectum.
Visible accumulation of small homogeneous epithelial cells lying in fibrous stroma. Microphoto. HC. 146.

Connective tissue and muscles elements are presented poorly and is surrounded by the alveoli.
In the literature are the three most significant histochemical sign of carcinoid: argentophile, argiropulo and chromaffin properties.
All these histochemical characteristics typical of the so-called "argentophile grains", located in the cytoplasm enterohromaffinnah cells.
Microscopic diagnosis of carcinoid installed during normal and special colors, is considered the most reliable (Thorson, 1958).
Pathological changes in the functioning of carcinoid do not differ from those with tumors without metastasis.