papilläres Adenom der Nieren
Papillary adenomas of the kidney are benign renal neoplasms arising from the renal tubular epithelium and almost always located within the cortex. They fall under the general category of renal adenomas, and are considered one of the commonest of renal epithelial neoplasms.
Epidemiology
The estimated prevalence rate is ~40% in patients older than 70 years of age (by autopsy series).
Clinical presentation
Most papillary adenomas are asymptomatic.
Pathology
As defined in the 2016 WHO classification, papillary adenomas are unencapsulated, low grade tumors with papillary or tubular architecture, measuring ≤1.5 cm in diameter (previous guidelines defined a size cutoff of 0.5 mm).
A papillary adenoma-to-carcinoma sequence has been described that is akin to similar transformation in colonic adenomas.
Adenomas are histologically characterized by papillary or tubular cytoarchitecture and frequent psammoma bodies.
Genetics
Cytogenetic changes of papillary adenomas include loss of the Y chromosome and combined trisomy of chromosomes 7 and 17. Histologic and genetic abnormalities of renal adenomas are indistinguishable from papillary RCCs.
Associations
- von Hippel Lindau disease
- acquired renal cystic disease, long-term haemodialysis
- these papillary adenomas may have different pathogenesis
Radiographic features
Papillary adenomas are usually extremely small (<15 mm) and may not be distinguished from other renal tumors (e.g. RCC/papillary renal carcinoma pRCC) and renal pseudotumors on imaging.
See also
- renal papillary adenomatosis - multiple papillary adenomas