Gaps in the internal elastic lamina (IEL) have been observed in arteries exposed to high blood flow. To characterize the nature and consequences of this change, blood flow was increased in the carotid arteries of 56 adult, male, Japanese white rabbits by creating an arteriovenous fistula between the common carotid artery and the external jugular vein. The common carotid artery proximal to the arteriovenous fistula was studied at intervals from 1 hour to 8 weeks after exposure to high flow. In the controls, the IEL showed only the usual, small, physiological holes, 2 to 10 microm in diameter. At 3 days, some of the holes in the IEL had become enlarged, but they could not be detected by scanning electron microscopy, despite manifest endothelial cell proliferation. At 4 days, gaps in the IEL appeared as small, luminal surface depressions, 15 to 50 microm wide. At 7 days, the gaps in the IEL had enlarged and formed circumferential, luminal depressions occupying 15+/-5% of the lumen surface. Endothelial cell proliferation persisted in the gaps while proliferative activity decreased where the IEL remained intact. At 4 weeks, as the artery became elongated and dilated, the gaps in the IEL widened as intercommunicating circumferential and longitudinal luminal depressions occupying 64+/-5% of the lumen surface. At 8 weeks, the rate of elongation and dilatation of the artery slowed and the widening of the gaps in the IEL diminished. Endothelial cells covered the gaps throughout. We conclude that flow-induced arterial dilatation is accompanied by an adaptive remodeling of the intima. The gaps in the IEL permit an increase in lumen surface area while endothelial cell proliferation assures a continuous cell lining throughout.

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A case of endometrioid adenocarcinoma arising from adenomyosis is reported. The patient was a 53-year-old woman who complained of vulvar itching. Smear cytology of the endometrium revealed adenocarcinoma. Magnetic resonance imaging of the pelvis revealed a lesion with a slightly high intensity in the uterine fundus on a T2-weighted image. Semiradical total hysterectomy and bilateral adnexectomy were performed, followed by chemotherapy. Histologically, the lesion in the uterine fundus was composed mostly of adenocarcinoma with stromal invasion. There were many adenomyotic foci in and around the carcinoma, including some showing transition to adenocarcinoma. There was no malignant finding in the normally situated endometrium. The carcinoma invaded in the myometrium, involving the uterine serosa, but no dissemination to the peritoneal cavity was found. The carcinoma was, therefore, considered to be endometrioid adenocarcinoma arising from adenomyosis. Immunohistochemistry showed expression of p53 oncoprotein and Ki-67 antigen in the carcinoma cells. The value of immunohistochemistry in predicting prognosis is discussed.

An autopsy case of aortic sarcoma who died of acute myocardial infarction caused by coronary involvement is reported. The patient was a 54 year old woman who was admitted because of an undiagnosed fever and general fatigue of 6 months duration. Magnetic resonance imaging (MRI) showed a tumor in the aortic arch. Total aortic arch replacement was performed. It was diagnosed as a malignant mesenchymal tumor of the aorta. The patient died of acute myocardial infarction 10 months after the operation. At autopsy, the tumor had invaded the luminal surface and intima of the proximal anastomosis (the remnant ascending aorta and the graft), the aortic valves, the distal anastomosis (surgical line of the thoracic aorta plus the graft), and the coronary arteries. The left main coronary artery showed complete obstruction by fibrin thrombus with tumor invasion in the intima, which was responsible for acute myocardial infarction. Primitive and bizarre tumor cells proliferated with many slit-like tissue spaces. Most of the tumor except for its luminal surface showed necrosis. Ultrastructurally, there were spaces between tumor cells, suggesting lumen formation, and some of them had microvilli. This sarcoma was considered to be the so-called aortic intimal sarcoma.

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