[Malignant tumor of the autonomic nervous system of the stomach (GAN-tumor)--case report of a new entity].

Gastrointestinal autonomic nerve (GAN)-tumors are extremely rare. So far seven cases of intestinal and four of gastric GAN-tumors were reported. GAN-tumors, also termed plexosarcomas, arise from autonomic nervous system plexuses of the gastrointestinal tract such as those of Meissner or Auerbach. We report a case of a metastatic gastric GAN-tumor in a 40-year-old woman. A small, 1 cm in diameter, submucosal plexosarcoma located in the posterior gastric wall and a 1.5 kg, 23 x 15 x 11-cm metastasis located retroperitoneally behind the stomach between liver, spleen and pancreas without discernable invasion of any of these organs were found. En-bloc resection of the retroperitoneal mass, the spleen, the pancreatic tail, and a part of the posterior gastric wall adhering to the mass were performed. In addition, lymph node metastases in splenic hilum were noted, and resected. In CT scan liver metastases were detectable fourteen months after surgery. The diagnosis is based on light microscopical, ultrastructural, and immunhistochemical analyses. The prognosis of GAN-tumors is fatal. In spite of radical excision 8 of 11 reported patients died few month after surgery while local recurrences and/or metastases in regional lymph nodes and in the liver were found. The response to chemotherapy was poor.