An unusual presentation of chordoma as a pyloric ring submucosal tumor: The first case report of a primary gastrointestinal lesion in humans.

INTRODUCTION AND IMPORTANCE: Chordomas are rare malignant bone neoplasms that are presumed to arise from chordal remnants in the fetal stage and typically occur along the axial skeleton. The extra-skeletal chordomas reported to date include soft tissue of the extremities and nasopharynx. Chordoma arising from the gastrointestinal wall has not been previously described. CASE PRESENTATION: We report on a 42-year-old man with primary chordoma presenting as a gastroduodenal submucosal tumor centered on the pyloric ring. The patient was consistently asymptomatic, and the tumor was an incidental finding. However, during a follow-up at approximately 1.6 years, an increase in tumor size was identified on computed tomography (CT), and surgical resection was performed without a definite pathologic diagnosis. The patient was successfully treated with distal gastrectomy, and the histological diagnosis was a conventional chordoma. The diagnosis was confirmed via immunohistochemical staining for brachyury, pan-cytokeratin, S-100, and SOX9. Postoperative CT and magnetic resonance imaging revealed no recurrence or metastasis during the 1.5-year follow-up period. CLINICAL DISCUSSION: Primary chordomas of the digestive tract are rare. Embryologic development of the notochord does not explain the existence of remnants in the gastrointestinal wall. Moreover, notochordal remnants, as precursors of chordoma, were not identified in the current case. The gastroduodenal chordoma may not have originated from embryonic notochordal remnants but through aberrant brachyury activation without a notochordal precursor. CONCLUSION: We report the first case of primary gastrointestinal chordoma in humans. The tumor was completely removed surgically, without postoperative recurrence.

[A endoscopic treatment of penetration of the colon by an ingested fish bone].

An 81-year-old woman was admitted complaining of left lower abdominal pain. Computed tomography on admission revealed foreign a body penetrating descending colon and free air. We extracted the foreign body endoscopically. The foreign body was a sharp-edged fish bone. She was treated by conservative medication without complication.

[Probable amebic brain abscess in a homosexual man with an Entamoeba histolytica liver abscess].

A 51-year-old Japanese-Brazilian homosexual man was admitted to a hospital because of fever, headache and right epigastralgia. He had been homosexual for 20 years. An abdominal CT revealed a liver abscess and microscopic examination of the pus of the drainage revealed cystic forms of Entamoeba histolytica. Oral administration of metronidazole 2,250 mg/day was started for amebic liver abscess. He complained of severe throbbing headache, and magnetic resonance imaging (MRI) of the brain showed a brain mass of approximately 2 cm in diameter in the right parietooccipital lobe. An amebic brain abscess was suspected and he was transferred to our hospital. Continuous oral administration of metronidazole for 49 days instead of invasive procedures gradually improved headache, fever and right epigastralgia. On the follow-up MRIs, the brain mass was gradually encapsulated, reduced its size, and finally disappeared. A diagnosis of amebic brain abscess was made on the basis of coexistent amebic liver abscess, MRI findings and a dramatic effectiveness to metronidazole. One should pay attention to E. Histolytica infection in the differential diagnosis of the abscess of the liver and brain since it has been increasing in Japan in recent years.

Clinical and genetic analysis of noncancerous and cancerous biliary epithelium in patients with pancreaticobiliary maljunction.

We analyzed clinical features and genetic alterations in the noncancerous and cancerous biliary lesions obtained from pancreaticobiliary maljunction (PBM) patients. Gallbladder (GB) and bile duct (BD) lesions were obtained surgically from 36 patients with PBM, and polymerase chain reaction (PCR) methods were used to examine for mutations of the K-ras gene and the p53 gene and for microsatellite instability (MSI). The 36 cases were clinically classified into two types according to whether extrahepatic bile duct dilatation was present: a congenital choledochal dilatation (CCD) group (n = 20) and a noncongenital choledochal dilatation (NCCD) group (n = 16). In the NCCD group, all 16 GB specimens exhibited hyperplastic, dysplastic, and cancerous (n = 9) lesions, but no pathological lesions were detected in the 12 BD specimens. On the other hand, in the CCD group, pathological examination revealed lesions, including 8 cancerous lesions, in 60% of the 20 GB specimens and lesions, and including 8 cancerous lesions, in 65% of the 20 BD specimens. K-ras mutations and MSI were detected in 33.3% and 0%, respectively, of 9 hyperplastic lesions, 28.6% and 85.7%, respectively, of 7 dysplastic lesions, and 60.0% and 80.0%, respectively, of 25 cancerous lesions (p <0.05; MSI in hyperplasia vs. dysplasia and cancer). There was no difference of the frequency in K-ras mutations and MSI between the NCCD and CCD groups. By contrast, p53 mutations were detected only in the cancerous GB lesions of both types, the rate being 35.3%. Genetic alterations of K-ras, MSI, and p53 are strongly associated with biliary tract cancer in PBM patients. MSI appears to contribute to carcinogenesis in the biliary tract mucosa of PBM patients, and p53 mutations may be related to the development of GB cancer in the CCD group.