Cystic Nephroma

Paediatric cystic nephroma is an exclusively cystic neoplasm with DICER1 mutations, in which the septa contain only fibrous tissue and differentiated tubules. The typical presentation is that of an abdominal mass, occurs slightly more commonly in boys than in girl, and most patients are aged < 24 months. Most paediatric cystic nephromas are well demarcated microscopically by a fibrous pseudocapsule, but a minority lack a pseudocapsule, either partially or completely. They are composed entirely of septated cysts lined by flattened, cuboidal, or hobnail epithelium, or they are denuded. The septa contain fibrous tissue with focal cellular condensations and well-differentiated tubules. The stroma labels for ER like many other cystic renal lesions. The presence of immature nephroblastic elements excludes the diagnosis of paediatric cystic nephroma and indicates cystic partially differentiated nephroblastoma. The lesions known as adult cystic nephromas belong to the mixed epithelial and stromal tumour family; unlike paediatric cystic nephroma, they typically contain ropy collagen and label for inhibin. Demonstration of DICER1 mutation is helpful in some cases. Paediatric cystic nephroma is treated with surgery only. Its prognosis is excellent, with 100% event-free and overall survival. Very rare cases of cystic nephroma transformation into DICER1 sarcoma have been described, but the risk is regarded as very low (The above text was taken from: WHO Classification of Tumours. Urinary and male genital tumours [Internet]. Lyon (France): IARC. 5th ed. 2022; vol. 8. Available from: https://tumourclassification.iarc.who.int/chapters/36).

See the chapter: Renal Neoplasms of our Tutorial (this chapter only has a Spanish version).

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WHO Classification of Tumours. Urinary and male genital tumours [Internet]. Lyon (France): IARC. 5th ed. 2022; vol. 8. Available from: https://tumourclassification.iarc.who.int/chapters/36.