Undifferentiated and anaplastic sarcomas are malignant mesenchymal tumors and are difficult to characterize microscopically. They often require immunohistochemistry to detect cellular markers to determine phenotype. Undifferentiated sarcomas lack distinctive features (eg, architectural patterns, cytoplasmic and nuclear features, cell products). Anaplastic sarcomas have most of the following features: variations in size and shape of nuclei, nuclear hyperchromasia, striking irregularity of chromatin pattern, abnormal mitotic figures, and large numbers of mitotic figures. Anaplastic sarcomas are generally undifferentiated; however, undifferentiated sarcomas do not have to be anaplastic.
In both cases, excision should be deep and wide, with 3-cm margins along with a combination of the intraoperative and followup oncologic therapy techniques described above, because the first surgery with immediate followup is most important in determining outcome. The prognosis is generally poorer for anaplastic sarcomas than for undifferentiated sarcomas.
Also see pet health content regarding tumors of the skin in dogs Tumors of the Skin in Dogs Tumors are abnormal growths of cells. Tumors affecting the skin or the tissue just under the skin are the most commonly seen tumors in dogs. Skin tumors are diagnosed more frequently than other... read more , cats Tumors of the Skin in Cats Tumors are abnormal growths of cells. Tumors affecting the skin or the tissue just under the skin are the most commonly seen tumors in cats. This is partly because they are the most easily seen... read more , and horses Tumors of the Skin in Horses Tumors are abnormal new growths of cells, also called neoplasms. Neoplasms affecting the skin or the tissue just under the skin are the most commonly seen tumors in horses. Skin tumors are diagnosed... read more .