CASE OF THE WEEK
2020-40 / October 5
Contributors: Daniel Athanazio
A woman in her 50s underwent a total nephrectomy for a 2.3 cm complex solid and cystic renal mass.
Quiz
1. What is the correct diagnosis?
a. Clear cell renal cell carcinoma with cystic changes
b. Clear cell tubulopapillary renal cell carcinoma with cystic changes
c. Cystic nephroma
d. Tubulocystic renal cell carcinoma
e. Multilocular cystic renal neoplasm of low malignant potential
1. b
1. Clear cell tubulopapillary renal cell carcinoma with cystic changes
Clear cell tubulopapillary renal cell carcinoma is an indolent tumor characterized by papillary and tubular growth. Tumor cells show clear cytoplasm and reverse polarity with apical located nuclei (nuclei align away from the basement membrane. Expression of cytokeratin 7, carbonic anhydrase IX (basolateral pattern, or “cup-shaped”) and GATA3 is useful to distinguish this tumor from the more aggressive conventional clear cell renal cell carcinoma.
Cystic change is common in clear cell tubulopapillary renal cell carcinoma. In some cases, the tumor may resemble multilocular cystic renal neoplasm of low malignant potential (MCRNLMP), as both may share dilated spaces lined by clear cell with bland cytology. The differential diagnosis of MCRNLMP with both clear cell and clear cell papillary carcinomas relies on the identification of solid areas within the tumor. Expansile growth confirmed microscopically excludes the diagnosis of MCRNLMP.
The presence of expansile growth within a predominantly cystic tumor with clear cells should prompt the pathologist to consider the diagnosis of a cystic form of clear cell renal cell carcinoma. Identification of this probably under-recognized cystic form of clear cell papillary renal cell carcinoma is important, given the indolent nature of this neoplasm.
Brimo F, Atallah C, Li G, Srigley JR. Cystic clear cell papillary renal cell carcinoma: is it related to multilocular clear cell cystic neoplasm of low malignant potential?. Histopathology. 2016;68(5):666-672.
Mantilla JG, Antic T, Tretiakova M. GATA3 as a valuable marker to distinguish clear cell papillary renal cell carcinomas from morphologic mimics. Hum Pathol. 2017;66:152-158.
Dhakal HP, McKenney JK, Khor LY, Reynolds JP, Magi-Galluzzi C, Przybycin CG. Renal Neoplasms With Overlapping Features of Clear Cell Renal Cell Carcinoma and Clear Cell Papillary Renal Cell Carcinoma: A Clinicopathologic Study of 37 Cases From a Single Institution. Am J Surg Pathol. 2016;40(2):141-154.
Moch H, Humphrey PA, Ulbright TM, Reuter VE. Chapter 1 Tumours of the Kidney. In: WHO Classification of Tumours of the Urinary system and male genital organs. Lyon: IARC; 2016. p. 40-41.
Daniel Athanazio
Federal University of Bahia
Imagepat, Laboratory of Pathology
Salvador, Bahia, Brazil
Kidney
Kidney Neoplasms; Clear Cell Tubulopapillary Renal Cell Carcinoma