7233 Gastrointestinal autonomous nerve tumor (gant) of the stomach: report of a case with preoperative eus assessment and eus guided fine needle aspiration biopsy.

Abstract

Background: Gastrointestinal autonomic nerve tumor is an uncommon stromal tumor of the intestinal tract and retroperitoneum originally described by Herrera et al. in 1984 under the name plexosarcoma. Since then, 69 cases have been reported with only 7 patients showing occurrence of multiple tumor locations. Biologic behavior seems to correlate with size and mitotic activity. Case report: A 22-yr-old female patient presented with fatigue and occasional upper abdominal pain. Laboratory data showed severe hypochromic anemia (hgb 5,4 mg/dl), physical examination did not show further pathology. EGD revealed a 2cm submucosal tumor in the posterior gastric wall with negative biopsy result. Abdominal sonography additionally showed an approx. 40 mm, partly echopoor, partly echofree lesion located between stomach and pancreas, without clear border to the pancreatic tail. CT scan revealed a 20 mm tumor of the gastric wall with strong contrast enhancement and a 45 mm hypodense tumor of uncertain origin. All other diagnostic procedures concerning anemia did not reveal any pathological results. Standard EUS with the Olympus GF UM 130 radial scanner showed on the site of the macroscopically polypoid lesion a 20 mm submucosal, echopoor-tumor of benign aspect (e.g. leiomyoma). The other, bigger lesion was located between the posterior stomach wall and the pancreatic tail, 40mm in diameter and of inhomogeneous echopoor structure, adjacent to the pancreas without clear border to the gastric wall. DD between a gastric or pancreatic lesion was demonstrated with an EUS guided fine needle aspiration (Pentax FG 32) showing strong evidence of a gastric mesenchymal tumor, compatible with leiomyoma or gastrointestinal stromal tumor (GIST). Preoperative MR confirmed the tumor findings, the bigger one probably originating from the gastric wall. Afterwards surgery was performed with an atypical stomach resection (R 0), revealing two GIST in the gastric wall (O 20 and 33 mm), immunohistochemically gastrointestinal autonomic nerve tumors (mitotic rate 7-12 per 50/HPF). Postoperative course was free of complications, and so far (6 month) with no recurrence of disease. Conclusion: To the authors knowledge, we present the 8th patient with multiple locations of this rare entity GANT, but the first case where EUS assessment is reported. The key examination was the endoscopic ultrasound guided fine needle aspriration biopsy, which was confirmed by surgery.