10 research outputs found
Mixed Type of Malignant Mesothelioma in an Aged Male ICR Mouse
Multiple whitish nodules in the thoracic cavity at the site of the thymus were observed
in a 101-week-old male ICR mouse. In a histopathological examination, the neoplastic cells
were predominantly fusiform in shape and proliferated in sarcomatoid growth patterns. Some
neoplastic cells showed epithelial growth patterns, such as the ductal structures. Mitotic
figures were frequently seen, and small necrotic foci and invasion to adjacent thoracic
organs were noted. In Alcian blue staining, bluish materials were observed between
fusiform-shaped cells and in some of the lumens of the ductal structures. In
immunohistochemistry, both fusiform-shaped and ductal structure-forming cells were
positive for vimentin and weakly positive to positive for cytokeratin. Based on the
aforementioned findings, the thoracic nodules were diagnosed as a mixed type of malignant
mesothelioma. This case was thought to be rare because of the very low occurrence of
spontaneous mesothelioma in mice