Noriko Motoi

Role of ras mutation in the progression of thyroid carcinoma of follicular epithelial origin.

The histological differentiation of thyroid carcinoma is known to correlate with prognosis. Ras oncogene mutations, which have been identified in various human cancers, have been suspected playing an important role in carcinogenesis and tumor progression. The purpose of this study was to clarify the mechanism of thyroid tumor progression, focusing on ras oncogenes. We examined ras mutations using nested polymerase chain reaction (PCR) and direct sequencing methods. The ras oncogene product was also examined immunohistochemically. Our results indicated that the incidence of ras mutations correlated with the histological differentiation of thyroid cancer. Three poorly differentiated carcinomas showed a higher rate of ras mutations than did 17 well-differentiated counterparts. Hot spots were not identified except for a relative accumulation of the N-ras gene at codon 61. There was a correlation between the immunoreactivity of the ras oncogene product and ras mutation, although the immunoreactivity of ras-p21 did not correlate with the histological differentiation. Mutation of the ras gene seemed to be one of the important events in the progression from well-differentiated carcinoma to poorly differentiated thyroid carcinoma.

Necrotizing Bacillus cereus infection of the meninges without inflammatory reaction in a patient with acute myelogenous leukemia: a case report.

Abstract A 64-year-old man in a severely immunocompromised state due to acute myelogenous leukemia died, respirator-unaided, about 10 h after the abrupt onset of coma. An earlier blood culture had yielded Bacillus cereus. The autopsy, performed 2 h after death, demonstrated diffuse subarachnoid hemorrhage without berry aneurysms, and the formalin-fixed brain was tinged with gray-brownish discoloration. The sections of the brain presented a whitish tint of the surface layer of all portion of the cerebral cortices, even those in the sulci. Histological examination of the brain revealed leptomeningeal B. cereus dissemination, and widespread necrosis of the leptomeninges and arachnoid vessels without inflammatory cell reaction. The grossly recognizable whitish surface layer of the cerebral cortex showed overt hyperchromatism, and contained neurons more degenerative than those located in the deeper cortical layer. The total absence of inflammatory reaction may be explained by a combination of the immunocompromised state of the patient and the character of B. cereus infection, which in itself induces little inflammatory reaction. The prominent lesions were confined to the cerebral surface layer and leptomeningeal tissue including the arachnoid vessels, which were all bathed in the cerebrospinal fluid, suggesting that some necrotizing toxins had been secreted into the fluid by the B. cereus. The necrosis of arachnoid vessels is thought to have in turn caused diffuse subarachnoid hemorrhage and marked disturbance of the cerebral blood flow, resulting in the terminal coma.

DEDIFFERENTIATED CHONDROSARCOMA OF THE RIB WITH A MALIGNANT MESENCHYMOMATOUS COMPONENT : AN AUTOPSY CASE REPORT

A rare variant of dedifferentiated chondrosarcoma wlth malignant mesenchymomatous component in a 57‐year‐old male is reported. The patient presented with a posterior mediastinal mass arising from the left eighth and ninth ribs showing well differentiated, low‐grade chondrosarcoma. Five years later, local recurrence occurred and an excised specimen also showed the same histological features as the primary tumor. Another 6 years later, the tumor recurred and metastasized to the multiple organs, the patient dying 4 months later. Autopsy revealed that the recurrent and metastatic tumors showed malignant mesenchymomatous ‘dedifferentiation’ of chondrosarcoma composed of rhab domyosarcoma, angiosarcoma, chondrosarcoma, osteosarcoma, and leiomyosarcoma, in addition to fibrosarcomatous areas. Although the less differentiated component of dedifferentiated chondrosarcoma usually shows the histological features of malignant fibrous histiocytoma and fibrosarcoma, multilineage differentiation can occur in that component. The phenomenon of ‘dedifferentiation’ in chondrosarcoma and the relationship to and distinction from malignant mesenchymoma of soft tissue and bone are discussed.

Bilateral choroidal metastases secondary to uterocervical carcinoma of the squamous cell type.

PURPOSEnTo report a patient with bilateral choroidal metastases secondary to uterocervical carcinoma of the squamous cell type.nnnMETHODSnCase report.nnnRESULTSnA 55-year-old woman complained of visual field loss and decreasing vision. Seven months earlier, uterocervical carcinoma of the squamous cell type was diagnosed and treated with chemotherapy and irradiation. Serous retinal detachment and choroidal masses were present in both eyes. Retinal detachment was lessened in both eyes after radiotherapy. The patient died of respiratory insufficiency 3 months after the appearance of choroidal metastases. At autopsy, there was no second cancer to cause the choroidal metastases. Tumor embolization was present in the choriocapillaries.nnnCONCLUSIONnChoroidal metastasis may develop from hematogenous spread of uterocervical squamous cell carcinoma.