[A case of gastrointestinal stromal tumor of the stomach mimicking a primary tumor of the omentum minus due to the extramural growth].

We report a case of gastrointestinal stromal tumor (GIST) of the stomach mimicking a primary tumor of the omentum minus. The tumor presented as an isolated mass in the omentum minus without any adhesion to the stomach. Microscopic examination revealed that the tumor pseudocapsule on the gastric side included a small smooth muscle tissue component. The patient was given a diagnosis of a gastric GIST that showed extensive extramural growth. GISTs should not be defined by the localization of the tumor.

Severe brainstem compression by an unruptured giant vertebral aneurysm--an autopsy case.

We describe an autopsy case of sudden unexpected death due to severe brainstem compression by an unruptured giant vertebral aneurysm. A 71-year-old male was found dead in his bedroom. The forensic autopsy revealed no severe trauma leading to his death. On internal examination, a giant intracranial aneurysm (3.4 x 2.6 x 2.7 cm) was observed on the trunk of the right vertebral artery. The aneurysm compressed the right side of the lower one-third of the pons and adjacent medulla oblongata. On sectioning, almost all of the aneurysm lumen was filled with a firm, clearly laminated organized thrombus. There was no evidence of subarachnoid hemorrhage. Histopathological analyses revealed congestion and hypoxic tissue changes in all organs examined. In microscopic sections of the giant vertebral aneurysm, thick fibrotic walls, intimal hyperplasia and organized thrombi in the lumen were found. Lots of intrathrombotic clefts with fresh erythrocytes were also observed. Moreover, Elastica van Gieson staining revealed fragmentation and disruption of the intimal elastic lamina in the aneurysmal wall. Collectively, we considered that some triggers in his daily life, including head rotation, might have caused the rapid onset of respiratory disturbance due to severe brainstem compression by a giant vertebral aneurysm.

Five-year survival following a medial pancreatectomy for an invasive ductal carcinoma from the body of the pancreas.

We report a rare case of a patient who survived for 5 years after undergoing a medial pancreatectomy for invasive ductal carcinoma originating from the body of the pancreas. A 63-year-old woman was diagnosed as a small cancer of the pancreatic body, and surgery was performed. Even though the tumor was a carcinoma, its small size prompted us to perform a medial pancreatectomy with regional lymph nodes dissection. Additional chemoradiation was performed and, five years after surgery, the patient is well with no signs of recurrence. Medial pancreatectomy for invasive ductal carcinoma has not ever been reported. Furthermore, long-term survival after a lumpectomy for invasive ductal carcinoma has never been reported in the literatures. The current case suggests that long-term survival in patients with invasive ductal carcinoma of the pancreas may be associated with the pathological or biological features of pancreatic carcinoma.

Detection of JC virus DNA sequences in colorectal cancers in Japan.

JC virus (JCV), a ubiquitous polyoma virus that commonly infects humans, was first identified as the etiologic agent for the fetal demyelinating disease, progressive multifocal leukoencephalopathy. Recently, a number of reports have documented detection of JCV in samples derived from several types of neural as well as non-neural human tumors. It has been suggested that oncogenicity of JCV depends on a T antigen having a strict structural homology to the T antigen of simian virus 40. To clarify whether JCV might have a potential role with regard to colorectal cancers, we investigated the presence of its genome in a series of cases along with colorectal adenomas and normal colonic mucosa, targeting T antigen, VP and agnoprotein by nested polymerase chain reaction and Southern blotting and T antigen by immunohistochemistry. While VP and agnoprotein were not found in any of the samples examined, T antigen was detected in 6 of 23 colorectal cancers (26.1%) and 1 of 21 adenomas (4.8%), but none of 20 samples of normal colonic mucosa. No clear and diffuse staining with anti-T-antigen antibodies (1:100) could be detected, and there was no correlation with CD20-positive cells, which might have indicated JCV latent infection of B lymphocytes. Presence of T antigen did not influence clinicopathological variables, including survival. In one colonic cancer case positive for T antigen together with lymph node metastasis, DNA extracted from cancer cells in the lymph node revealed no detection of T antigen. Our results are in the intermediate position between the high T antigen rate (81%) in one report and the lack of it (0%) in another focused on colon cancers. It was concluded that T antigen might be integrated in cancer cells in approximately one fourth of Japanese colon cancer cases without clear and diffuse expression of the protein, suggesting a possible role in oncogenesis which might involve a hit-and-run mechanism.

A fatal case of pontine hemorrhage related to methamphetamine abuse.

In this report, we describe a fatal case of pontine hemorrhage related with methamphetamine abuse. A 54-year-old male was found dead in a prone position in his parents' house, and a medico-legal autopsy was carried out to determine the cause of his death. Externally, although an injection mark-like injury with subcutaneous hemorrhage was observed in the left cubital fossa, the autopsy revealed no severe trauma leading to death. Internally, every organ was moderately congested. The brain weighed 1330 g. Macroscopically, there was no vascular abnormality such as aneurysm or malformation. In the sections of the brain stem, a massive hematoma occupied the central area of the pons. Drug screening test using Triage was weakly positive for amphetamines. Moreover, in the blood and urine samples, methamphetamine was quantitatively detected at concentrations of 0.4 and 0.6 mg/l, respectively, by gas chromatography-mass spectrometry. Other drugs and poison were not detected in the blood and urine samples collected at autopsy. Histopathologically, necrotizing angiitis characterized by fibrinoid necrosis of the intima and media was observed with cell infiltration. Thus, the pontine hemorrhage seemingly resulted from methamphetamine-induced angiitis, with an acute elevation of blood pressure after methamphetamine abuse.

Opposite roles of neutrophils and macrophages in the pathogenesis of acetaminophen-induced acute liver injury.

Neutrophils and macrophages infiltrate after acetaminophen (APAP)-induced liver injury starts to develop. However, their precise roles still remain elusive. In untreated and control IgG-treated wild-type (WT) mice, intraperitoneal APAP administration (750 mg/kg) caused liver injury including centrilobular hepatic necrosis and infiltration of neutrophils and macrophages, with about 50% mortality within 48 h after the injection. APAP injection markedly augmented intrahepatic gene expression of inducible nitric oxide synthase (iNOS) and heme oxygenase (HO)-1. Moreover, neutrophils expressed iNOS, which is presumed to be an aggravating molecule for APAP-induced liver injury, while HO-1 was mainly expressed by macrophages. All anti-granulocyte antibody-treated neutropenic WT and most CXC chemokine receptor 2 (CXCR2)-deficient mice survived the same dose of APAP, with reduced neutrophil infiltration and iNOS expression, indicating the pathogenic roles of neutrophils in APAP-induced liver injury. However, APAP caused more exaggerated liver injury in CXCR2-deficient mice with reduced macrophage infiltration and HO-1 gene expression, compared with neutropenic WT mice. An HO-1 inhibitor, tin-protoporphyrin-IX, significantly increased APAP-induced mortality, implicating HO-1 as a protective molecule for APAP-induced liver injury. Thus, CXCR2 may regulate the infiltration of both iNOS-expressing neutrophils and HO-1-expressing macrophages, and the balance between these two molecules may determine the outcome of APAP-induced liver injury.