Ovarian Carcinoma with Skeletal Metastasis in a Yacare Caiman (Caiman yacare)
A 39-yr-old intact adult female Yacare caiman (Caiman yacare) presented with hindlimb paresis. Magnetic resonance imaging and computed tomography studies revealed a compressive vertebral mass in the lumbar spine associated with a large left pelvic osseous mass and multiple extensive osteolytic lesions in both the axial and appendicular skeletons. Because of the severity and extension of the osseous lesions, euthanasia was elected. Gross necropsy findings included bilateral, hardened, irregular ovaries and multifocal pale, thickened bone marrow. Histopathologic findings were consistent with an ovarian carcinoma with metastasis to the pelvis, vertebrae, and femurs. Reproductive neoplasms with skeletal metastasis should be added to the differential diagnoses for nonspecific progressive and chronic wasting or lameness in intact aging crocodilians.Abstract
(A) Transverse T2-weighted Fast Spin Echo (FSE) magnetic resonance imaging (MRI) image of the pelvis at the level of the second sacral 4 vertebra (S2). A large, slightly heterogenous, lobulated mass (M) with some hyperintense foci (arrow) is seen at the level the left coxo-femoral joint (asterisk), protruding in the pelvic canal and focally compressing the uroproctodeum (UP). LFH, left femoral head; RFH, right femoral head. (B) Right lateral oblique view of a three-dimensional, volume-rendered computed tomographic (CT) image of the pelvis (Horos v. 2.1.1, Horos Project, Annapolis, Maryland, MD), depicting the extensive osteolysis in the left acetabulum (asterisk) and left ischium (arrow). A smaller, similar osteolytic lesion is also visible in the right femoral head (arrowhead). LP, left pubis; RF, right femur; RI, right ischium; RP, right pubis. (C) Transverse T2-weighted FSE MRI image (top) of the first sacral vertebra (S1) and transverse CT image at the same level (bottom). There is an ill-defined mass with cystic component (asterisk) in the vertebral body, right pedicle, dorsal lamina, and spinous process of S1 (arrowhead), with corresponding areas of osteolysis (arrow) on the CT image. Adjacent epaxial muscles (EM) are hyperintense on MRI. SC, spinal cord. (D) Sagittal multiplanar reconstruction of CT images acquired with high-resolution algorithm, showing multiple osteolytic lesions in various vertebrae (asterisk) with several compressive pathological fractures (arrow). Lu, lungs.
(A) Postmortem photograph of the coelomic viscera showing a hardened and irregular ovary (star). Multiple follicles are adhered to the oviduct and mesovarium (arrowhead). (B) Ovary, carcinoma. Highly cellular, non-encapsulated, and poorly demarcated mass infiltrating the adjacent ovarian tissue with marked squirrous reaction and extensive multifocal osseous metaplasia (arrowheads). Hematoxylin, phloxine, and saffron stain, × 20. Bar = 3 mm. (C) Ovary, carcinoma. Cuboidal to spindle-shaped neoplastic cells organized in irregular trabeculae and nodules supported by an abundant connective stroma, with few mitotic figures observed (arrow). Hematoxylin, phloxine, and saffron stain, × 400. Bar = 50 µm. (D) Left femoral head, metastasis of ovarian carcinoma. Infiltration by densely packed clusters of neoplastic cells (stars) in osseous tissue and bone marrow. H&E stain, × 20. Bar = 3 mm.
Contributor Notes
3 Current address: Health Sciences Centre, Ontario Veterinary College, University of Guelph, 50 Stone Road, Guelph, ON, N1G 2W1, Canada
