A CASE OF DUODENAL CARCINOID REVEALED NEGATIVE GRIMELIUS NITRATE STAIN

Duodenal carcinoid is a relatively rare entity. It is believed that the carcinoid can be diagnosed by Grimelius nitrate stain because of its perfect positive response to the staining. We experienced a case of asymptomatic duodenal carcinoid, which was negative to Grimelius nitrate stain and ultrastructural examination revealed few neurosecretory granules. A 62-year-old man was pointed out an elevated lesion with ulcer on the top in the duodenal bulb by an occasional fiberscopic examination for endoscopic infusion therapy. Biopsy revealed a low malignant neuroendocrine tumor and negative Grimelius nitrate stain. Because of poor general status due to liver cirrhosis and esophageal varices, we had followed this tumor for 17 months by fiberscope examinations, until a partial resection of the doudenum was performed. Ultrastructural examination of the resected specimen revealed few neurosecretory granules in the cytoplasms, which might participate with the negative response to Grimelius nitrate stain. The tumor was diagnosed with carcinoid.