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4 slides generated from the cancer page, with a quiz from the open benchmark and speaker notes that cite the sources. Arrow keys move between slides; Print gives one slide per page.
Clear cell papillary renal cell tumour is a small, low-grade kidney tumour that looks like a mix of clear cell and papillary kidney cancer but behaves harmlessly: no case has been reported to spread. The WHO renamed it from carcinoma to tumour in 2022 for that reason. It is common in people with kidney failure and is cured by removing it.
The 2016 WHO classification recognised clear cell papillary renal cell carcinoma as a type, and the 2022 edition renamed it clear cell papillary renal cell tumour because no metastasis has been documented (Moch 2016; Moch 2022). It is composed of clear cells lining cystic, tubular and papillary structures with nuclei aligned away from the basement membrane, is strongly CK7-positive with cup-shaped carbonic anhydrase IX staining, and lacks the VHL alterations and 3p loss of clear cell carcinoma and the trisomies of papillary carcinoma. In 55 tumours from 34 patients (8 with end-stage renal disease), tumours were 0.2 to 7.5 cm (mean 2.0), 87 percent grade 2 and 96 percent stage pT1a, multiple in 9 patients (Modern Pathology 2013). In 290 consecutive nephrectomies it was the fourth most common type, average age 58, a third associated with end-stage renal disease, all pT1, and two cases had been misclassified as clear cell carcinoma (Human Pathology 2014).
How it differs from its parent: it is the renal cell tumour that is not, in behaviour, a cancer; misclassifying it as clear cell carcinoma can lead to over-treatment and to unnecessary VHL testing.
| Setting | Approach | Guideline |
|---|---|---|
| All cases | Partial nephrectomy or active surveillance of a small mass; no systemic therapy. | not mapped |