Malignant Inflammatory Fibrous Histiocytoma in a Pointer Dog

Malignant fibrous histiocytomas (MFHs) is the most common type of soft tissue sarcoma in the old animal with a aggressiveness, a high local recurrence rate and significant metastatic rate, which associated with a poor prognosis. In most histologic and immunohistological studies, the tumor cells raised from a fibroblastic and/or myofibroblastic phenotype, presumably from undifferentiated mesenchymal cell origin. MFHs are usually firm and invasive, arising in the subcutis; metastasis depends on tumor grade (many are grade 3) [1,2]. The primary tumor cells are pleomorphic, varying in appearance from fusiform to round. Often nucleoli are prominent and irregular [5]. Extracellular amorphous eosinophilic material may be prominent and likely represents reactive collagen production by the tumor [5]. (omitted)