GASTROINTESTINAL AUTONOMIC NERVE TUMOR OF THE COLON - A CASE-REPORT WITH IMMUNOHISTOCHEMICAL AND ULTRASTRUCTURAL STUDIES

Gastrointestinal autonomic nerve tumor (GANT) is an uncommon subtype o f gastrointestinal stromal tumor that is morphologically similar to co nventional stromal tumors but has ultrastructural features of neural d ifferentiation. Of the approximately 58 cases of GANT reported to date , most have arisen in the small intestine or stomach, but none, to our knowledge, in the colon or rectum. Accordingly, we report the first c ase of colonic GANT and document its histologic, ultrastructural, and immunohistochemical characteristics. These were not unlike those of GA NT arising elsewhere in the alimentary tract, including interlacing sp indle cells, skenoid fibers, axonal cytoplasmic processes, dense core neurosecretory granules, and immunoreactivity to vimentin and NSE. The rarify of GANT in the large intestine should not preclude ultrastruct ural evaluation of colorectal stromal tumors for neural features.