Tubulocystic renal cell carcinoma
Tubulocystic renal cell carcinomas are a rare subtype of renal cell carcinoma (RCC) with predominantly cystic appearance.
Tubulocystic RCC was first identified as a distinct histopathologic entity in 2005, and subsequently acknowledged as an independent disease category in the 2016 WHO classification of renal tumors 1,3.
Peak incidence occurs in the 6th through 8th decades.
Males are much more commonly affected than females (7:1 ratio).
- papillary renal cell carcinoma coexists in the same kidney in up to 50% (in small cases series 2)
Most patients are asymptomatic and the tumor is discovered incidentally.
Macroscopically, the tumors are well-circumscribed lesions comprising extensive tiny cysts with numerous thin septa, resulting in a spongy or "bubble wrap" appearance. Microscopically, the tumor is composed of tubular and cystic spaces separated by fibrous stroma.
Limited information from genetic studies suggest gene expression similar to papillary RCC 4.
- markedly hyperechoic (70%)
- posterior acoustic enhancement (50%), consistent with cystic nature
- no internal vascularity on color Doppler
- variable attenuation so may appear solid or cystic
- C+: contrast enhancement is usually mild or indeterminate given small amount of solid tissue
- T2: hyperintense due to cystic component, with septa
- T1 C+ (Gd): mild enhancement in small solid components or wall
Treatment and prognosis
Surgical resection is curative. Recurrence and/or metastasis occur in less than 10% of cases.
- cystic renal tumors
- hyperechoic renal tumors
- 1. Cornelis F, Hélénon O, Correas JM, Lemaitre L, André M, Meuwly JY, Sengel C, Derchi L, Yacoub M, Verkarre V, Grenier N. Tubulocystic renal cell carcinoma: a new radiological entity. (2016) European radiology. 26 (4): 1108-15. doi:10.1007/s00330-015-3923-9 - Pubmed
- 2. Zhou M, Yang XJ, Lopez JI, Shah RB, Hes O, Shen SS, Li R, Yang Y, Lin F, Elson P, Sercia L, Magi-Galluzzi C, Tubbs R. Renal tubulocystic carcinoma is closely related to papillary renal cell carcinoma: implications for pathologic classification. (2009) The American journal of surgical pathology. 33 (12): 1840-9. doi:10.1097/PAS.0b013e3181be22d1 - Pubmed
- 3. Moch H, Cubilla AL, Humphrey PA, Reuter VE, Ulbright TM. The 2016 WHO Classification of Tumours of the Urinary System and Male Genital Organs-Part A: Renal, Penile, and Testicular Tumours. (2016) European urology. 70 (1): 93-105. doi:10.1016/j.eururo.2016.02.029 - Pubmed
- 4. Delahunt B, Srigley JR, Montironi R, Egevad L. Advances in renal neoplasia: recommendations from the 2012 International Society of Urological Pathology Consensus Conference. (2014) Urology. 83 (5): 969-74. doi:10.1016/j.urology.2014.02.004 - Pubmed