4 research outputs found
Spontaneous Subcutaneous Sarcoma in a 50-week-old Male Wistar Hannover GALAS Rat
A subcutaneous mass was noted in the abdomen of a 50-week-old male Wistar Hannover GALAS
rat. Histologically, the tumor was composed of vimentin-positive small round cells with
scant cytoplasm arranged in a trabecular, sheet or pericytoma-like pattern and spindle
cells arranged in a bundle pattern and vimentin-negative round cells proliferating in an
island-shaped pattern. Argentophilic thin fibers were observed to wrap up the individual
cells, and some of the tumor cells showed coexpression of vimentin and cytokeratin that
formed juxtanuclear globes in the cytoplasm by double immunohistostaining. Transmission
electron microscopy did not reveal any characteristic features suggesting cellular
differention toward a specific cell type. Based on these findings, it was difficult to
specify the origin, and the tumor was diagnosed as a poorly differentiated mesenchymal
tumor and classified as a sarcoma, NOS (not otherwise specified)