Gastrointestinal stromal tumor

Gastrointestinal stromal tumor is a rare mesenchymal tumor in the gastrointestinal tract. GISTs account for only about 1-3% of all malignancies of the gastrointestinal tract.

Since a GIST becomes apparent only through a certain amount of specific symptoms, a diagnosis is often made very late in the course of the disease, or it may happen at random after routine examinations. When the tumor reaches a certain size, it manifests itself with symptoms such as bowel obstruction, abdominal pain, perforation, and chronic bleeding, followed by a black stool, anemia, and swelling of the abdomen. 

Cause of GISTs is a gene defect. The KIT gene is mutated, resulting in permanently active and abundantly many KIT receptor proteins, thus leading to more extensive cell division.

The mutation seems to occur sporadically, only in very few patients a familial accumulation is observed.