Allotransplantation of a spontaneous malignant fibrous histiocytoma in the ddY mouse.

Malignant fibrous histiocytoma (MFH) developed spontaneously in the subcutaneous tissue of the hind leg of a 7-month-old female ddY mouse. Histologically, an original tumor was composed of an admixture of fibroblast-like and histiocyte-like cells arranged in predominantly storiform or cartwheel pattern. The tumor was serially transplanted into syngeneic mice up to the 70th generation. Moreover, the tumor was also consistently transplanted into allogeneic mice of several inbred strains. Allogeneic mice used in the present study were 7 strains having the different H-2 haplo-types. During succeeding passages, transplanted tumor pieces showed aberrant growth properties. Histopathological features of these tumors were basically similar to original tumors. As mentioned above, a spontaneous MFH in the ddY mouse was consistently transplantable into both syngeneic and allogeneic mice. The tumor was designated S-MFH-1T.