Transrectal Ultrasonography of a Small Rectal Carcinoid Tumor with Lymph Node Metastasis: A Case Report

A 27-year-old woman with a small rectal carcinoid tumor wasexamined by transrectal ultrasonography (TRUS) for preoperativestaging. TRUS revealed regional lymph node involvement, in additionto a 10-mm hypoechoic tumor invading into, but not through,the submucosa. The lymph node involvement was confirmed preoperativelyby TRUS-guided needle biopsy. Although the digital examinationfindings indicated local excision was appropriate, in accordancewith TRUS and TRUS-guided biopsy findings, the patient underwentradical surgery. The TRUS findings of lymph node involvementand depth of invasion were confirmed histologically. The patientis alive and disease-free 35 months postoperatively. These observationssuggest that TRUS reveals the regional lymph node involvementand the depth of invasion of rectal carcinoid tumors accuratelyand, therefore, helps in selecting appropriate treatment.     

Lysosomes of rat liver and dab carcinogenesis

The relationship between DAB carcinogenesis and changes of lysosomes in rat liver was investigated. After 40 days of treatment with DAB, nodules and an abnormal cell population, containing small, large and degenerative cells, appeared. Corresponding to these changes, the S/P ratio of lysosomal enzymes such as acid RNase and β-glucuronidase increased to two or three times the normal value. These alterations were considered along with some histochemical observations on β-glucuronidase. A possible participation of these lysosomal enzymes in carcinogenesis is discussed.     

Mesenchymal cells infiltrating a bladder acellular matrix gradually lose smooth muscle characteristics in intraperitoneally regenerated urothelial lining tissue in rats

OBJECTIVE: To characterize serial long-term histological changes in mesenchymal cells infiltrating a collagen-based matrix, as in a hollow organ with differentiated urothelial lining created intraperitoneally by grafting cultured urothelial cells, mesenchymal cells with smooth-muscle immunohistochemical characteristics infiltrated into the scaffold, despite no mesenchymal cells being seeded into the scaffold before grafting. MATERIALS AND METHODS: To regenerate a urothelial lining tissue intraperitoneally, rat urothelial cells were cultured and seeded with the feeder-layer technique onto bladder acellular matrix (BAM). After 7 days of cultivation to attach urothelial cells on the BAM, the matrix was folded with the urothelial cells inside and grafted onto the mesentery of the previously partially cystectomized rat. RESULTS: The grafted urothelial cells on the BAM, which formed a monolayer before grafting, stratified into three to four layers as early as 4 days after grafting. Although the regenerated urothelium became thinner with time, there was urothelial stratification and a peculiar angular appearance on the apical surface of the regenerated urothelium even after 56 days. The mesenchymal cells infiltrating the BAM showed positive immunohistochemical staining to alpha-smooth muscle actin or desmin at 7 days. Subsequently, the number of actin- or desmin-positive cells gradually decreased with time. On transmission electron microscopy, the infiltrating mesenchymal cells were characterized as myofibroblasts at 7 days. Smooth muscle-like cells were identified at 14 and 28 days, and fibrocytes were the main population at 56 days. CONCLUSIONS: Although epithelial-mesenchymal interactions have been assumed to be one of the most critical factors in smooth-muscle development, mesenchymal cells infiltrating the scaffold in this intraperitoneal regeneration model gradually lost smooth muscle characteristics with time. These results suggest that interactions between cultured urothelial cells and infiltrating mesenchymal cells alone could not maintain the smooth muscle character of infiltrating mesenchymal cells.     

Hepatic resection of giant metastatic tumor from clear cell carcinoma of the ovary

All cancer patients, particularly those treated for colorectal cancer, should be monitored for the presence of liver metastases, but liver metastases from ovarian clear cell carcinoma are quite rare. We report a patient subjected to extended left hepatectomy due to a giant metastasis 5 years after surgical treatment for an ovarian neoplasm that was histopathologically diagnosed as clear cell carcinoma. A 58-year-old woman had undergone hysterectomy and bilateral salpingo-oophorectomy due to ovarian cancer (stage Ic). Four years and 8 months after the operation, a computed tomography (CT) scan demonstrated a giant tumor in the left lobe of the liver. The tumor compressed the inferior vena cava (IVC), but it was not clear whether it invaded the vessel. She received chemotherapy for 4 months; however, the tumor did not decrease in size. She was subsequently referred to our institution and was submitted to operation after it was confirmed that there were no distant metastases. After being subjected to an extended left hepatectomy and cholecystectomy, the patient recovered from the surgery without any complications. She has been carefully followed for 17 months and has presented no evidence of recurrence.