Fibrosarcoma with lung and lymph node metastases in an Asian elephant (Elephas maximus).

A case of fibrosarcoma with lung and lymph node metastases in a 54-year-old female Asian elephant (Elephas maximus) is described. After pododermatitis of 2 years duration in the right forefoot, a mass developed in the lateral toenail. At postmortem, metastasis to the right axillary lymph node and both lungs was noted. Microscopic examination of primary and metastatic sites revealed infiltrating bundles of spindle cells, with fairly distinct cell borders, variable amounts of eosinophilic cytoplasm, and elongate or oval nuclei. Tumor cells were often arranged in interwoven bundles and herringbone patterns. Mitotic figures were numerous and frequently bizarre. The diagnosis of fibrosarcoma with lung and lymph node metastases was made on the basis of histologic features and positive immunohistochemical staining for vimentin.