A case of carcinoid tumor of the stomach, which was observed in such a young boy 15 years of age, is reported. The patient was admitted to the 1st Division of Internal Medicine, with the chief complaints of faintness or transiently lost vision sensation on standing-up and heaviness of the left flank, that have appeared on and off without noticeable cause until 3 July, 1971 when he saw us for the first time since he was 10 years old, although not always but very frequently. He has had no remarkable past illness, but was mentally and physically retarded to such a degree that he was unable to start walking by himself. Meanwhile, ever since he was 5 years old, the flushing of the face has been noticed already, but no other signs of carcinoid syndrome were seen. At the time of his admission, the thin patient was found to have hypochromic anemia, which was treated by iroh therapy with success, without any other abnormalities on biochemical, urine and feces examinations. Radiologic as well as endoscopic (gastrocamera with fiberscope) examination revealed that there was a semicubic tumor covered with normal gastric mucous membrane but with bridging folds at the antrum of the posterior wall, indicative of submucous tumor of the stomach. So the tumor was immediately operated on. The resected stomach showed that the tumor in question was a submucous tumor of the stomach, 22×15×12 cm in size, elastic hard in consistency, cubic in shape, and the cut surface of the tumor was yellowish-white, partly brown, in color. Histology of the tumor pointed to carcinoid tumor of the stomach, argentaf f inity of which was, however, found negative by Masson-Fontana staining. Seven months after the operation, the patient remains quite normal. It should be noted for reference that his serum serotonin level and urinary 5-HIAA excretions as measured after the gastric resection were 67-143, μg/1 and 6.0 mg/day. respectively.
