Spontaneous nephroblastoma with oncocytic differentiation in a Japanese White rabbit

Abstract

Spontaneous nephroblastoma is an uncommon tumor in laboratory rabbits. We recently encountered this tumor, and we describe its histological characteristics in this report. A male 3-year-old Japanese White rabbit (JW/kbs), maintained as a stock animal, suddenly showed poor condition and was found dead a few days later. At necropsy, a large mass was found that extended from one side of the renal pelvis. The cut surface of the mass was dark red in color and velvety to the touch. The kidney on the contralateral side was normal. Microscopically, the tumor mass consisted of biphasic components, which consisted of epithelial (tubular and glomerular) and blastemal (nodular) elements. No sarcomatous proliferation was observed. In addition, some of the tubules were lined by cells with a large amount of eosinophilic cytoplasm. The cells were confirmed as oncocytes by immunohistochemical and electron microscopic examinations. The present case was therefore diagnosed as a nephroblastoma with oncocytic differentiation.

Nephroblastoma in a Sprague Dawley rat unrelated to titanium dioxide nanoparticle exposure in utero

“…A similar population of epithelial cells were present in the nodules identified on the serosal surface of liver, pancreas, stomach and small intestine. Rare instances of metastatic spread of neoplastic cells to thoracic cavity (lungs) and abdominal cavity have been recorded (Hard & Grasso, 1976; Katsuta et al., 2017; Mesfin & Breech, 1992; Potkay & Garman, 1969). Interestingly, specific strains of rats are genetically predisposed to this renal tumour (Sprague Dawley subline [Upj:TUC(SD)spf.nb]; Mesfin & Breech, 1992).…”

“…In domestic animals, this tumour has a poor prognosis even with therapeutic intervention, and metastasis has been known to occur to the lymphatic system, lungs and liver (Montinaro et al., 2013). In laboratory mice, rats and rabbits, the occurrence of nephroblastoma is rare (Katsuta et al., 2017; Mesfin & Breech, 1992). Nephroblastomas often develop during foetal life and are not detected until the animal becomes symptomatic, usually later in life (Mesfin & Breech, 1992).…”