Chondrosarcoma with undifferentiated neoplastic cell proliferation around the distal tibiotarsus bone in a wild Hooded crane (Grus monacha).

An adult male Hooded crane was found dead on the Izumi plane. At autopsy, subcutaneous nodules were found around the medial and lateral sides of the left distal tibiotarsus bone. The largest cross-section of the masses revealed a multilobular pattern, with small amounts of viscous mucus. Histopathologically, the nodules were composed of three types of neoplastic cells: chondrocytic cells with abundant lightly basophilic cartilaginous matrices, mesenchymal cells and a small portion of the neoplastic tissue consisted of undifferentiated neoplastic cells exhibiting a high mitotic count and frequent multinucleation. This is the first case of a chondrosarcoma including undifferentiated neoplastic cell proliferation in a wild Hooded crane.