Metastatic Chondrosarcoma in a Corn Snake (Pantherophis guttatus)
An approximately two-year-old corn snake (Pantherophis guttatus) presented with a swelling of the mandible. The animal was treated for two months with no response. Unfortunately, the snake's condition deteriorated and it was euthanized. Grossly, the mass in the mandible was yellow–white and replaced normal bone and soft tissue of the jaw. Additional masses were noted in the heart, kidney, lung, pancreas, and eye. The mass in the mandible was comprised of a sheet of amorphous basophilic material resembling typical cartilage matrix with slightly irregular lacunar spaces. Tumor cells had abundant cytoplasm, vesicular or hyperchromatic nuclei, and prominent nucleoli. Mitotic figures were not seen. Scattered foci of neoplastic cartilaginous cells were noted in the heart, lung, kidney, pancreas, and eye. The final diagnosis for this case was secondary chondrosarcoma. Chondrosarcomas are not considered a common form of neoplasia in reptiles. When it is diagnosed, it appears to be more commonly associated with the vertebral column. Chondrosarcomas should be considered in the differential list for snakes (or other reptiles) that present with masses associated with the bone or cartilage.Abstract

Area of mandibular swelling and discoloration (arrows) attributable to a chondrosarcoma.

Cut section of mandible to illustrate the replacement of normal tissue by neoplastic cartilage (A).

Multiple foci of metastatic chondrosarcoma in both the atrium and ventricle of the heart of a corn snake (arrows). Some foci are large and have the gross appearance of cartilage, whereas others are less well differentiated from myocardial tissue.

Multiple masses of metastatic chondrosarcoma in the kidney of a corn snake.

Section of metastatic renal chondrosarcoma illustrating the smooth, glistening appearance of the tumor.

Metastatic chondrosarcoma replacing myocardium. The cartilage is fairly well differentiated, and scattered lacunae contain two chondrocytes (arrows). Hematoxylin and eosin.

Additional detail of Figure 6. Note the smooth tumor margins. Hematoxylin and eosin.

Metastatic chondrosarcoma in the lung of a corn snake. Hematoxylin and eosin.

Metastatic chondrosarcoma in the eye of a corn snake replacing and impinging upon the retina (A). Hematoxylin and eosin.