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clear cell tubulopapillary renal cell carcinoma

Monday 15 November 2010

Definition: "Clear cell tubulopapillary renal cell carcinoma," constitute a unique subtype in the spectrum of renal epithelial neoplasia based on their characteristic morphologic and immunohistochemical features.

Low-grade renal cell tumors

Recently several low-grade renal cell tumors, distinct from those recognized by the 2004 World Health Organization classification of renal tumors, have been described. These tumors had similar clinicopathologic features, being low-stage tumors with cystic, tubuloacinar, and/or papillary architecture.

The tumor cells were low grade with variable amounts of clear cytoplasm that was positive for cytokeratin 7 (CK7), but negative for CD10.

Genetic changes characteristic of clear cell or papillary renal cell carcinoma were not seen in these tumors.

Synopsis

- mean age: 60.4 , range: 26 to 88.
- Sex ratio 1/1
- 10% bilateral tumors
- mostly cystic
- prominent fibrous capsule and stroma
- variable amount of cysts, papillae, tubules, acini, and solid nests
- branching tubules and acini
- anastomosing clear cell ribbons with low-grade nuclei

Immunochemistry

- strongly positive for CK7
- variably positive for CA9
- negative for CD10
- negative for α-methylacyl-CoA racemase and TFE-3.

Cytogenetics

- No CGH anomaly
- 1/36 tumor: gains of chromosomes 7 and 17 (20924276)
- no deletion of 3p (20924276)
- 1/36 : low copy number gains of chromosomes 7 and 17 (20924276)
- no VHL gene mutation and promoter methylation (20924276)

References

- Clear cell tubulopapillary renal cell carcinoma: a study of 36 distinctive low-grade epithelial tumors of the kidney. Aydin H, Chen L, Cheng L, Vaziri S, He H, Ganapathi R, Delahunt B, Magi-Galluzzi C, Zhou M. Am J Surg Pathol. 2010 Nov;34(11):1608-21. PMID: 20924276