Excess of cancer in patients receiving renal transplantation is well-known in Western countries, but information in Japan remains limited. Our study examined whether excess risk is found in patients receiving renal transplantation in Japan. Between 1970 and 1995, 1155 males and 589 females underwent renal transplantation in 6 hospitals, and a total of 12,982 person-years of observation was accumulated. Malignancies developed in 2.6% of patients; O/E ratio was 2.78. Median interval from renal transplantation to tumor development was 58 months. The interval in the patients receiving medication with cyclosporine-A (CyA) (median, 42.5 months) was significantly shorter than that with non-CyA (median, 95.5 months). Median age at the diagnosis of malignancy was 40 years, which is much younger than that in the general population. Relative risk was highest in renal cancer, followed by thyroid cancer, malignant lymphoma and uterine cancer. A distribution of malignancies was different from that reported from Western countries. These findings showed the excess risk of malignancies in Japan with renal transplants, especially in male patients, similar to that observed in Western countries, though the types of malignancy were different.

It has been considered that gastric large B cell lymphoma mainly consists of mucosa-associated lymphoid tissue lymphoma (MALToma) with large cell transformation. However, debate continues about the cell lineage. We analyzed 61 operated cases of gastric B cell lymphoma, mainly focusing on 40 cases of diffuse large cell lymphoma (DLCL). Immunohistologically, two cases were classified as CD10-positive follicular lymphoma, 19 cases were low-grade MALToma, 11 CD10-negative DLCL with a component of low-grade MALToma (high-grade MALToma), 12 CD10-positive DLCL, and 17 CD10-negative DLCL without MALToma (pure DLCL). Lymphoepithelial lesion (LEL) was found in all -cases of high-grade MALToma, and in eight of these its invasion was confined to the mucosa and submucosa. Expression of Bcl-6 was detected in two cases of high-grade MALToma. Only two cases of CD10-positive DLCL had large cell LEL, and seven cases showed tumor invasion beyond the submucosa. All 12 cases were positive for Bcl-6, and a delicate meshwork of CD35 (Ber-MAC-DRC)-positive follicular dendritic cells was detected in eight cases. Pure DLCL of all 17 cases reached the proper muscle layer or more, and expression of Bcl-6 was detected in 10 cases. For patients with pure DLCL, overall survival was significantly (p <0.05) worse than those of high-grade MALToma and CD10-positive DLCL by Kaplan-Meier and log-rank methods. Clinical staging and Bcl-6 expression were also good prognostic factors in patients with DLCL. Three groups of gastric DLCL each had unique histologic findings, immunohistologic characteristics, and prognosis.

Based on the large celloidin‐embedded section method, human mandibles from 62 autopsied carcinoma cases were examined histologically to determine the pathological characteristics of any mandibular metaslases. Metastasis was confirmed histologically in 10 (16%) of the 62 cases and was comparatively frequent with gastric and pulmonary carcinomas. The hemopoietic areas in the mandibular marrow seemed to favor the early deposition of tumor cells. These micrometastatic foci seemed to increase in size, spreading to all parts, including the periodontal tissue or anterior part of the mandibular body. Increased hemopoietic activity following lodgement, seemed to play an important role for further metastases. Roentogenographic examination did not seem to be the best method of detecting metastasis.