Paediatric Pathology Online: Wilms' Tumour Related Lesions

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Cystic partially differentiated nephroblastoma is a demarcated lesion composed of cysts often with a hobnail epithelial lining, and with Wilms' tumour-like tissue in their walls.

This lesion is adequately treated by excision alone in children, and is distinguished from cystic Wilms' tumour by the absence of any solid area resembling nephroblastoma.

- Cystic partially differentiated nephroblastoma.Australas Radiol. 2006 Jun;50(3):255-7

- Partially differentiated cystic nephroblastoma.Rev Chil Pediatr. 1991 Mar-Apr;62(2):124-7

- Partially differentiated cystic nephroblastoma.An Esp Pediatr. 1986 Sep;25(3):195-9.

- Cystic partially differentiated nephroblastoma and polycystic Wilms tumor: a spectrum of related clinical and pathologic entities.J Urol. 1983 Mar;129(3):577-80

-Cystic partially differentiated nephroblastoma: a clinicopathologic entity in the spectrum of infantile renal neoplasia.Cancer. 1977 Aug;40(2):789-95.

Metanephric (nephrogenic) adenofibroma arises deep in the kidney and consists of spindle cell stroma, and nodules of papillary and tubular epithelial elements with psammoma bodies. The spectrum of metanephric adenofibroma and related lesions: clinicopathologic study of 25 cases from the National Wilms Tumor Study Group Pathology Center.Am J Surg Pathol. 2001 Apr;25(4):433-44

Metanephric adenofibroma: report of a case and review of the literature.Am J Surg Pathol. 1999 Jun;23(6):727-33.

Nephrogenic adenofibroma. A novel kidney tumor of young people.Am J Surg Pathol. 1992 Apr;16(4):325-34.

Nephrogenic adenofibroma is a novel kidney tumor of young people (mean age of presentation, 13 years), who present with polycythemia, hypertension, or hematuria, which resolve following nephrectomy. The typical nephrectomy specimen contains a solitary, nonencapsulated, vaguely circumscribed, irregularly shaped or spherical, firm mass with either tan, gray-white, or pale yellow coloration. Cysts are sometimes present within the tumor. The histologic appearance is distinctive and characterized by a marked proliferation of spindled mesenchymal cells resembling the classical type of congenital mesoblastic nephroma, encasing discrete nodules of embryonal epithelium similar to the hyperplastic nephrogenic rests (nephroblastomatosis) usually associated with Wilms' tumor. The mesenchymal component consists of a fascicular proliferation of tightly interlaced, uniform, benign-appearing spindled cells that immunostatin for vimentin and fibronectin, but not desmin or actin. The epithelial component consists of discrete islands of blastemal cells that are partially or fully differentiated toward tubular, tubulopapillary, or papillary structures. Psammoma bodies are plentiful. Embryonal epithelium immunostains for cytokeratin but not epithelial membrane antigen. The overall histologic appearance of the mesenchymal and epithelial components is benign, and preliminary clinical data suggest that the tumor has a benevolent course. Two cases, however, contained small, well-circumscribed papillary lesions near the renal pelvis that resembled low-grade collecting duct carcinoma. The clinical implications of the latter finding are unclear.

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Metanephric adenoma is composed exclusively of epithelium with characteristic small dark cells arranged in tiny tubules and papillary formations also often with psammoma bodies.

-Metanephric adenoma vs. Wilms' tumor: a report of 2 cases with diagnosis by fine needle aspiration and cytologic comparisons.Acta Cytol. 2007 May-Jun;51(3):464-7.

-Metanephric neoplasms: the hyperdifferentiated, benign end of the Wilms tumor spectrum?Clin Lab Med. 2005 Jun;25(2):379-92.

-Metanephric adenoma in an 8-year-old child: case report and review of the literature.J Pediatr Surg. 2005 May;40(5):e25-8

-Metanephric adenoma of the kidney.Int J Urol. 1999 Apr;6(4):200-2

-Metanephric renal adenoma.Arch Esp Urol. 1998 Jan-Feb;51(1):78-80

- Metanephric adenoma. Clinicopathological study of fifty patients.
Am J Surg Pathol. 1995 Oct; 19(10):1101-14.