Gastrointestinal stromal tumors are the most common mesenchymal neoplasia with some specificities that other mesenchymal neoplasia never have. Firstly, the tumor cells express receptor tyrosine kinase (KIT) and CD34 as well as interstitial cells of Cajal (ICCs). The fact suggests that GISTs may originate from ICCs. Secondly, we found the c-kit gene gain-offunction mutations that contribute to the oncogenesis of GISTs. Thirdly, molecular target therapy by the tyrosine kinase inhibitor is effective to patients with GISTs. The effectiveness has a close relation to the second specificity. We describe molecular mechanisms and therapies of GISTs here.

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We investigated risk factors for lymph node metastasis of early gastric cancer, and extended the indication of endoscopic rnucosal resection (EMR)for early gastric cancer as follows; 1) in the lesions of I type, differentiated type of mucosal cancer less than 20 mm in sire, 2) in the lesions of IIa type, differentiated type of mucosal cancer less than 40 mm in size, 3) in the lesions of IIc type, differentiated type of mucosal cancer without ulceration less than 20 mmin size, and undifferentiated type of mucosal cancer without ulceration less than 15 mm in size, and differentiated type of mucosal cancer less than 20 mm in size, associated with ulceration limit to upper third of submucosal layer. On the other hand, the indication before extending is as folloWS ;1) in the lesions of I type, differentiated type of mucosal cancer less than 20 mrn in size, 2) in the lesions of IIa type, differentiated type of mucosal cancer less than 20 mm in size, 3) in the lesions of IIc type, differentiated type of mucosal cancer without ulceration less than 10mm in size. EMR was performed with 2-channeled scope method for 251 1esions which correspond to the both indication in the last six years. We analysed the lesions, and devided them into two groups; group A) 139 1esions which correspond to the indication before extended, and group B) 112 1esions which correspond to the extended indication. The results are as follows; 1) On average, we followed up the lesions of group A for 21.5 months, and the lesions of group B for 18.7 months. 2) The rate of bleeding during EMR was 6.5%of group A, and 9.8%of group B. The rate of bleeding after EMR was 9.4%of group A, and 17.0%of group B. There was no significant difference between group A and group B. Ail of the cases of bleeding were treated by endoscopy. Perforation did not occur. 3) Concerning cancer residue, we analysed 172 1esions which were followed for more than a year. Cancer residue vvas seen in three lesions (3.2%) of group A, and in five lesions (6.5%) of group B. There was no significant difference between group A and group B. 4) Mean operation time was 30.1 minutes in group A, and 47.0 minutes in group B. We could treat all of them within 54 minutes en average. In conclusion, we considered it is possible to extend the indication of EIVIR.

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A 22-year-old woman was admitted to our hospital because of fever of unknown origin and heartburn. Upper gastrointestinal endoscopy showed discrete erosions surrounded by elevatedmucosa in the lower esophagus. Colonoscapy showed edematous mucosa and multiple apthoiderosions in the ileocecum. Non-caseating epithelaid granulomas were shown by biopsiedspecimen from the terrninal ileum. Histologic examination of biopsy specimens from theesophagus demonstrated inflammatory cells infiltration tivithout granuloma formation, compatible with Crohn's disease. Clinical symptoms disappeared and laboratory data became normalby the treatment with elemental diet and Mesalazine. The patient was discharged from thehospital on the 49th hospital days.

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A 59-year-old man presented with general fatigue and appetite loss. Abdominal CTshowed multiple metastatic liver tumors. Endoscopy revealed multiple gray whitish polypoidand suhmucosal tumors in the esophagus. A diagnosis of malignant lymphoma was made by thehistological findings. Chemotherapy was initiated, however, the lesions changed to blackappearance, and primary malignant melanoma of the esophagus(PMME)was diagnosed. Fivemonths hater, the patient died of carcinomatosis despite the chemotherapy. For correctdiagnosis of light-colored esophageal tumors, the amelanotic type of PMME should be includedin the differential diagnosis.

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We used the tyrosine kinase inhibitor imatinib mesylate in a patient with a primary gastrointestinal stromal tumor(GIST). In March 1999, a 85-year-old man visited to ourhospital with upper abdominal discomfort and tarry stool. Submucosal tumor, 4.0cm indiameter, was detected on the greater curvature of the stomach. On CT, the tumor invaded tothe pancreas, left kidney and retroperitoneum. Immunohistochemical analysis of the lesionrevealed the expression of CD34 and CD117, and he was diagnosed as having unresectablemalignant GIST. The patien.t then agreed to participate in the treatment program of imatinibafter informed conserlt. Treatment with three 100-mg capsules of imatinib once daily wasstarted in January 2002. Subsequ.ent CT scans showed that tumor had decreased to less than6%in volume after 12 months of imatinih treatment. Subjective adverse effects were only slightand transient edema of eyelid. The result suggest that inhibition by imatinib mesylate of thec-kit tyrosine kinase of GIST woud be an effective therapy for primary GIST tumors.

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A 70-year-old man was admitted our hospital with right flank pain and ascites. Tuberculous peritonitis was suspected, because of the high ADA level of ascites. For an accuratediagnosis, laparoscopy was performed. A laparoscopic examination showed some tiny white nodules in the peritoneum. Biopsy specimens of peritoneum revealed epithelioid cellgranulomas and Langhans'giant cells. Laparoscopic examination was useful for the clinicaldiagnosis of tuberculous peritonitis. Recently, the incidence of tuberculous peritonitis has beendecreasing since the introduction of effective chemotherapy against Mycobacterium Tuberculosis. The diagnosis of tuberculous peritonitis is quite difficult because the symptoms are notspecific for the disease and the incidence of occurrence are relatively rare. We report a caseof tuberculous peritonitis with a review of 72 cases of tuberculous peritonitis seen in theJapanese literature.

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This is a case report of a 85Ryear-old female with carcinoma in the cervix of the uterus.She was under radiotherapy (45 Gy of external irradiation and 20 Gy of internal irradiation)since April 199. In November of the same year, she noticed fresh blood on defecation. Colonoscopy was carried out on December 1, 2000, and a readily bleeding teleangiectatic lesion was detected in the anterior wall of the lower segment of the rectum and consequently she was diagnosed as havirlg radiation proctitis. For this lesion, argon plasma coagulation(APC)was carried out three times with 40 w of high frequency output and argon gas flow rate of 0.41/min to 0.61/min. After this treatment, only a small part of the teleangiectatic lesion remained with no more bleeding. Management of sueh lesion by this therapeutic modality involved less pain and very minimal invasiveness. Therefore, it was suggested that this therapy is effective for the treatment of readily bleeding teleangiectatic lesions such as class l Sherman radiation colitis.

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A 25-year-old man, who had admitted to other hospital with a complaint of abdominal pain, was transferred to our hospital for the further examination and therapy. Duodenoscopic examination showed the tumor at the 2nd part of the duodenum. Abdominal CT, MRI and angiography showed an 8-cm sized hypervascular tumor in the head of the pancreas. Serum concentrations of gastrin, glucagon and VIP were slightly elevated. Biopsy specimen showed malignant endocrine tumor and pylorus preserving pancreaticoduodenostomy was performed. The histological diagnosis was malignant endocrine tumor of the pancreas. Immunohisto-chemical examination of the tumor revealed positive immunoreactivity for ACTH, glucagons and VIP. We report a rare case of the malignant endocrine tumor of the pancreas with widespread invasion to the 2nd part of the duodenum.

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