Cystic nephroblastoma of an aged dog

A blastema-predominant canine renal nephroblastoma with gingival metastasis: case report and literature review

Nephroblastomas are uncommon embryonal tumors in dogs. We report herein a blastema-predominant nephroblastoma with gingival metastasis in an 8-y-old Miniature Pinscher dog. Histologically, the mass was composed mainly of blastemal elements with minor epithelial and mesenchymal differentiation. Metastatic masses in the gingiva had histologic and immunohistochemical features similar to those of the primary renal nephroblastoma. Neoplastic cells were extensively positive for both vimentin and PAX8, and scattered positive for cytokeratin. Using the clinical staging of human Wilms tumor, we staged our case as stage IV with <4 mo of survival time. We summarized previous studies of canine renal and spinal nephroblastomas, and analyzed the correlations among clinical staging, histologic classification, and mean survival time of dogs with renal nephroblastomas. Clinical staging was significantly correlated with survival time, as shown in humans. In dogs, however, additional factors can potentially influence the outcome of treatment and disease development.

Malignant Nephroblastoma in a Common Marmoset (Callithrix jacchus)

Necropsy of a 17-month-old male common marmoset ( Callithrix jacchus) with a history of increased abdominal girth resulted in the finding of a unilateral polycystic renal neoplasm. Detailed histopathologic and immunohistochemical investigations revealed different tissue types within the tumor including stromal connective tissue and fusiform mesenchymal cell formations surrounding blastemal cells as well as different developmental stages of organ-specific epithelial cells accompanied by extensive cyst formation. Metastases were not observed. In consideration of the macroscopic, histologic, and immunohistochemical findings, the tumor was classified as a nephroblastoma closely resembling the so-called Wilms' tumor, a malignant embryonic renal tumor frequently observed in humans, especially in young children. In contrast, this tumor entity has rarely been observed in nonhuman primates. This report represents the first documented case of a cystic variant of nephroblastoma in a nonhuman primate.

A malignant nephroblastoma in an aged fox (Fennecus zerda)

A malignant nephroblastoma with pulmonary metastasis which was found at necropsy in an old fox is described. This is the first report of such a tumour in a fox. Nephroblastoma is rare in the family Canidae and usually occurs in young individuals. The presence of a tumour arising from embryonal tissue in an aged animal raises questions about the genesis and behaviour of this tumour. The tumour may have contributed to the animal's congestive heart failure as a result of the generalized pulmonary involvement, an erythropoietin-induced polycythaemia, or increased peripheral resistance via the renin-angiotensin system.