Abstract
A tumor developed spontaneously in the subcutaneous tissue of the hind leg of a 7-month-old female ddY mouse. Light and electron microscopical examinations revealed that the original tumor was composed of an admixture of fibroblast-like and histiocyte-like cells arranged predominantly in a storiform or cartwheel pattern. The tumor cells gave positive reactions for acid phosphatase, N-acetyl-β-glucosaminidase, non-specific esterase, β-glucuronidase, alpha-1 antitrypsin and fibronectin. The original tumor was diagnosed as a malignant fibrous histiocytoma (MFH). The tumor was serially transplanted into syngeneic mice up to the 92nd generation. The tumor was also consistently transplanted into allogeneic mice of several inbred strains. The allogeneic mice used in the present study were strains having different H-2 haplotypes. During succeeding passages, transplanted tumors showed aberrant growth properties. The tumor transplanted into mice of inbred strains took well to back transplantation for mice of original strain and allotransplantation for other inbred strains. The pathological features of these transplantable tumors were basically similar to those of the original tumor. As mentioned above, a MFH developed spontaneously in the ddY mouse was consistently transplantable into both syngeneic and allogeneic mice.
