Adult papillary renal tumour with oncocytic cells

Definition

A proposed distinct variant of papillary renal cell carcinoma with an extensively papillary architecture and oncocytic cells.

Clinical features

All ten reported patients were male with a median age of 71 years.

Macroscopic appearances

Tumours were intrarenal and well demarcated (pT1N0).

Histopathology

The tumour forms thin papillae with a thin fibrous core lined by a single layer of oncocytic cells having deeply eosinophilic finely granular cytoplasm. Nuclei are round with central nucleoli. The cores of the papillae contain numerous lipophages. Haemorrhage and necrosis are common. The mitotic rate is low. Hale's colloidal iron stain is negative.

Immunohistochemistry

	Antimitochondrial antibody	10/101
	AMACR	10/101
	Vimentin	10/101
	CD10	10/101
	e-cadherin	5/101
	Renal cell carcinoma marker	4/101
	Cytokeratin 7	3/101
	Cyclin D1	2/101
	EMA	1/101
	MUC1	1/101
	CD117	0/101

Differential diagnosis

Oncocytoma: lacks a papillary architecture or necrosis.
Papillary carcinoma: the cells are not oncocytic. Type II tumours have eosinophilic cytoplasm but differ in showing high grade cytology. There is characteristically trisomy of chromosome 17.

Prognosis

All patients were tumour free at a median of five years after radical nephrectomy.

References

1 Lefevre M, Couturier J, Sibony M, et al. Adult papillary renal tumor with oncocytic cells: clinicopathologic, immunohistochemical, and cytogenetic features of 10 cases. Am J Surg Pathol 2005; 29:1576-81