No abstract

Cronkhite-Canada syndrome is generally accepted to be a benign disorder, with 374 reported cases to the present. Worldwide, there have been 18 previously reported cases of Cronkhite-Canada syndrome associated with gastric cancer. In this report we describe a case of a 52-year-old man with the clinical features of Cronkhite-Canada syndrome combined with gastric cancer. Although the gastric tumor was located at the antrum of the stomach, we performed a total gastrectomy because of the edematous swelling and high risk of malignancy in the remnant stomach. As Cronkhite-Canada syndrome may be a premalignant condition for gastric cancer, as well as for colorectal cancer, we suggest periodic examination of the stomach, colon, and rectum for patients with Cronkhite-Canada syndrome.

Metastatic pancreatic cancer is rare, accounting for approximately 2% of all pancreatic malignancies, and most cases arise from renal cell carcinoma. We report the case of a 63-year-old woman, who presented with a pancreatic tumor detected during her annual health examination. She had undergone left nephrectomy 13 years previously for renal cell carcinoma. Computed tomography (CT) revealed two tumors in the head and body of the pancreas, a hypervascular tumor and a hypovascular tumor with an enhanced rim, respectively. She underwent pylorus-preserving pancreaticoduodenectomy, and metastatic pancreatic tumors arising from the kidney with clustered clear cell carcinoma immunohistochemically positive for CD10 were diagnosed. This report presents the different enhancement features of different lesions on CT scans. Because the enhancement features of lesions have been reported to vary according to the size of the metastatic tumor, a knowledge of the history of renal cell carcinoma is crucial for diagnosis.

The mechanism of artificial and spontaneous metastases of tumor was analyzed in B16 melanoma cells and C57BL/6 mice by using anti-asialo GM1 antibody and anticancer agents. Single administrations of 500 micrograms anti-asialo GM1 antibody resulted in significantly decreased NK activity in spleen cells of C57BL/6 mice, lasting 10 days from the day following administration. Treatment with anti-asialo GM1 antibody never decreased the function of T lymphocytes measured by blastogenesis with phytohemagglutinin or T cell growth factor. The tumoricidal functions of activated macrophages but not of resident macrophages were decreased by in vivo treatment with anti-asialo GM1 antibody. The anti-asialo GM1 antibody was evaluated in terms of the enhancing effect on pulmonary metastases with regard to the timing of administration. Treatment with anti-asialo GM1 antibody 1 day before or on the day of tumor inoculation resulted in a substantial increase in the number of artificial pulmonary metastases. In the experimental system of spontaneous metastases, anti-asialo GM1 antibody most effectively increased the number of pulmonary metastases when administered 1-2 weeks before the removal of primary tumor, when the tumor cells are thought to be released into blood circulation from the primary site. In addition, accelerated growth of transplanted tumors at the primary site was observed in mice treated with anti-asialo GM1 antibody. These results strongly suggest that anti-asialo GM1 antibody enhances the incidence of in vivo tumor metastases and the growth of transplanted tumor mainly by suppressing the function of NK cells. The maximum effective dose (MED) of mitomycin C or its derivative (M-83) suppressed NK activity significantly, and pretreatment with these anticancer agents enhanced the growth of the artificial pulmonary and liver metastases. In contrast, the MED of cDDP showed no effect on the NK activity or the numbers of pulmonary and liver metastases. These results indicate that the depression of NK activity induced by chemotherapy results in the promotion of metastatic disease. From these studies it can be concluded that NK cells have a key role in the control of metastases of malignant disease, and that support of NK activity is very important for the prevention of metastases.