Nephroblastoma with lymphatic metastasis in an Angus calf: scientific communication

Nephroblastoma is a congenital renal neoplasm composed of metanephric blastema and stromal cells. A one-year-old male Angus calf presented with diarrhea, nasal discharge, cough and weight loss. Serum levels of creatinine and urea were increased, with reduction in the level of albumin. After eight days, clinical condition got worse and the calf died. On necropsy, the cranial pole of the left kidney presented a firm whitish mass (30 x 21 x 14 cm). Multifocal to coalescing firm whitish nodules were observed on the serosa of the large intestine, in the mesentery and in the adventitia of the urinary bladder. All lung lobes contained multifocal to coalescing firm whitish elevated nodules (0.5 to 1 cm of diameter). Histologically, renal mass consisted of neoplastic proliferation of embryonal epithelial and mesenchymal cells, intermixed with large amounts of blastema cells. The nodules on large intestine, mesentery, urinary bladder and lungs were composed mainly of blastema cells and mild amount of mesenchymal cells. Blastema cells were also observed within lymphatic vessels in lung parenchyma. Embryonal epithelial, mesenchymal and blastema cells showed, respectively, positive immunostain for cytokeratin, vimentin and S100. Based on pathological and immunohistochemical findings, the tumor was diagnosed as nephroblastoma in a calf with metastasis through lymphatic vessels to lungs, large intestine, mesentery and urinary bladder.