Hirofumi Nakatsuka

Primary anorectal malignant melanoma: report of a case.

Primary anorectal malignant melanoma is a fairly uncommon but highly malignant disease. This disease is sometimes mistaken for such benign conditions as either a hemorrhoid or rectal polyp. We herein describe a case of early primary malignant melanoma of the anal canal. In this case, magnetic resonance (MR) imaging was found to be useful for diagnosing the melanotic melanoma. We especially emphasize the usefulness of a fat-saturation MR image in distinguishing melanotic melanoma from other rectal tumors.

Comparison of proliferative activities and metastases between two subtypes classified at the deeply infiltrating sites of colorectal moderately differentiated adenocarcinomas

Twenty‐eight moderately differentiated adenocarcinomas invading beyond the muscularis propria of the colorectum were subclassified as 13 moderate‐ and 15 poor‐subtype tumors based on the histology at the deeply infiltrating sites. Moderately differentiated cancer cells were correlated with liver metastasis and p53 immunoreactivity. Poorly differentiated cancer cells were correlated with lymph node metastases but not to p53 immunoreactivity. The proliferative cell nuclear antigen (PCNA) labeling index (LI), Ki‐67 LI and agyrophilic nuclear organizer regions (AgNOR) values determined for the poorly differentiated cancer cells in the poor‐subtype tumors were significantly lower than those of moderately differentiated cancer cells in the moderate‐subtype tumors. In cells from tumors classified as poor‐subtype, poor differentiation was associated with decreased PCNA LI levels, but with unchanged Ki‐67 LI and AgNOR values. These results Indicate that colorectal adenocarclnoma cells that are histologically subclassified as moderately differentiated have different proliferative and metastatic activities from cancer cells that are poorly differentiated. Moderately differentiated cancer cells are associated with hematogen‐ous metastasis to liver and high proliferative activity, and loss of tubular formation of cancer cells may be fundamentally related to lymph node metastasis and infittrative growth.

Multiple primary cancers: with reference to atomic bomb survivors in Hiroshima.

We treated 44 patients with multiple primary cancers, at the Second Department of Surgery, Hiroshima University, during the 14 year period from 1968–1981. The total number of malignant tumors was 1,934 during this period, thus the incidence of multiple primary cancers was 2.3 per cent. Nine of the 44 were atomic bomb survivors in Hiroshima and were characterized by the frequent incidence of the second tumor about 30 years after exposure to the atomic bomb. In addition, the second tumor tended to develop later in patients prescribed radiotherapy for the first tumor. As for the site of tumor, there was no tendency of more frequent development of tumors in organs highly sensitive to radiation other than the thyroid.

Carcinoma Cells at Deeply Infiltrated Sites: Role in Development of Metastases in Patients with Advanced Colorectal Adenocarcinomas

Carcinoma cells that infiltrate beyond the muscularis propria (“ss” lesions) have a significant role in developing metastases in patients with advanced colorectal carcinoma. Examination of 363 resected colon carcinomas revealed a high frequency of metastasis when carcinoma cells invaded beyond the muscularis propria. The metastases found in 170 patients with advanced colorectal adenocarcinomas invading this tissue were divided into five groups according to the histology of the ss lesions and the overall predominant histology. Lymph node metastasis was significantly increased as the histologic grade of the ss lesion decreased. Poorly differentiated adenocarcinoma cells were rapidly infiltrative regardless of the proliferative state and were associated with peritoneal dissemination, distant metastasis, or local recurrence. In contrast, moderately differentiated adenocarcinoma cells were more proliferative with reduced expression of E-cadherin compared to well differentiated adenocarcinoma; they were closely associated with liver metastasis and overexpression of p53. In the DNA ploidy study, there was a relation between decreased histologic differentiation and an increased likelihood of changes of the DNA ploidy pattern. Overexpression of α2β1- and α4β1-integrins of carcinoma cells preceded disruption of the cadherin system, which was associated with the morphologic change, and were correlated with the high metastatic properties of the carcinoma cells. Tumor classification based on histology in the ss is a good indicator of metastasis or prognosis of advanced colorectal adenocarcinomas. Further study based on these findings will facilitate understanding of the metastasis.