Gastrointestinal autonomic nerve tumor of the esophagus: A clinicopathologic, immunohistochemical, ultrastructural study of a case and review of the literature

Abstract

BACKGROUND. Gastrointestinal autonomic nerve (GAN) tumor is a rare tumor that is supposed to originate from the enteric autonomic plexus. The tumor is a sub-group of the gastrointestinal stromal tumor that usually occurs in the stomach and small intestine. METHODS. An intramural tumor located in the upper third of the esophagus of a 62-year-old Chinese female is reported. The tumor was removed by a three-phased esophagogastrectomy because of its large size. The tumor measured 6.5 cm x 5 cm x 4 cm. Its tissues were sampled, examined by light microscopy, immunohistochemistry, and electron microscopy. RESULTS. The tumor was vaguely encapsulated but had foci of partial infiltration of the capsule. It was comprised of spindle cells with moderate nuclear pleomorphism. The mitotic count was less than 1 per 10 high-power field. The tumor stained positive for vimentin, neuron specific enolase (NSE), and S 100 protein, and was negative for cytokeratins, synaptophysin, chromogranin, neurofilaments, muscle markers, HMB45, and CD34. Ultrastructural study revealed that the tumor had cytoplasmic processes interdigitated in a complex fashion that were held together by primitive junctions but not invested in basal lamina. Many neurosecretory granules and neurotubules were also noted. The diagnosis was GAN tumor of the esophagus. From previous reports, 43 cases (25 males, 18 females) of GAN tumor of other locations have been documented. The tumors were located almost exclusively in the stomach and small intestine: rare cases arose primarily in the retroperitoneum and mesentery. Some of these GAN tumors were observed in patients with Carney's triad (three cases), neurofibromatosis (two cases), and adrenal ganglioneuroma (one case). It appears that the biologic behavior of GAN tumors is aggressive but there are too few reports on which to conclude anything about their prognosis. The tumors are usually large, with low mitotic rate, and are positive for NSE and negative for muscle markers. CONCLUSIONS. To the authors' knowledge, this is the first time that GAN is described in the esophagus. The diagnosis can be made only on the basis of characteristic ultrastructural features.