Intralobar Nephroblastematosis in a Nine-week-old Wistar Rat

Abstract

Intralobar nephroblastematosis (ILNB) is a precursor lesion to the development of nephroblastoma (NB) in rats. Unilateral ILNB was observed in the kidney of a nine-week-old female Wistar rat (Crl:WI) from a short-term toxicity study. Clinical pathology and urinalysis did not reveal altered renal function. This microscopic, unencapsulated lesion consisted of basophilic sheets of blastemal cells that did not include a prominent mesenchymal component. These cells expanded in the interstitium, which trapped and compressed few normal renal tubules. The blastemal cells moderately differentiated to form rosettes, primitive tubules, and a glomeruloid body. Multifocally, the lumen of primitive tubules contained eosinophilic secretions with basophilic material in the center. The diagnostic criteria used were compared and differentiated with renal dysplasia, nephrogenic rest, NB in rats, and with that of the identical lesion in children.

Arachidonic acid supplementation does not affect N-methyl-N-nitrosourea-induced renal preneoplastic lesions in young Lewis rats

“…It is characterized by discrete clusters of highly basophilic blast cells surrounding mature ducts and organoid differentiation as epithelial rosettes, primitive basophilic tubules, attempted glomerulus formation or mature epithelial ducts (20,21). Nephroblastomatosis is a small, solitary, basophilic cell mass consisting of densely crowded blast cells with ill-defined cytoplasm and basophilic nuclei and a few signs of early organoid differentiation into epithelial rosettes (20,22,23). Nephroblastomatosis has the potential to develop into a nephroblastoma as it grows, and is regarded as a preneoplastic lesion of nephroblastoma (24).…”

A case report of RccHan^TM: WIST rat with multiple neoplastic and non-neoplastic proliferative lesions

“…Differentiation into muscular, cartilaginous, osseous, or vascular tissues is not generally identified in rat nephroblastoma 9 , 12 . Nephroblastematosis is considered as a precursor of nephroblastoma and is characterized by a small, solitary, and basophilic cell mass consisting of blast cells in the outer medulla, and is sometimes associated with primitive tubular and glomerular structures 10 , 14 . The blastemal cells displace the existing renal tubules and form rosettes and alveolar structures.…”

“…The blastemal cells displace the existing renal tubules and form rosettes and alveolar structures. Nephroblastematosis is usually grossly invisible in rats; however, when grossly visible, it fully develops into neoplastic tissue, that is, nephroblastoma 14 , 15 . Renal dysplasia is a developmental anomaly in the kidneys, and renal components are often present with hypoplasia.…”