Renal neoplasia with papillary architecture involving the pelvicalyceal system

• Published in: Human pathology 2021-01, Vol.107, p.46-57
• Main Authors: Gupta, Sounak, Cheville, John C., Galeano, Belinda K., Sukov, William R., Herrera-Hernandez, Loren, Reed, Katelyn A., Lohse, Christine M., Thompson, R.Houston, Boorjian, Stephen A., Leibovich, Bradley C., Jimenez, Rafael E.
• Format: Article
• Language: English
• Subjects: BRAF p.V600E–mutated RCC; Cloning; Deoxyribonucleic acid; DNA; FH p.Lys477dup; Kidney cancer; Nephrogenic papillary renal neoplasia; Papillary renal cell carcinoma; Pathology; Patients; Pelvicalyceal system; Polymorphism; Sinuses; Staging; Tumors
• ISSN: 0046-8177; 1532-8392
• DOI: 10.1016/j.humpath.2020.10.013

Pelvicalyceal system (PS) involvement by renal cell carcinoma (RCC) is staged as pT3a disease (American Joint Committee on Cancer [AJCC], 8th edition). As papillary RCC (PRCC) has been infrequently represented in studies looking at the prognostic impact of PS involvement, we reviewed our institutional cohort of 8225 cases for PS involvement by PRCC. Nine such cases were subjected to histopathologic review and immunohistochemistry. Fluorescence in situ hybridization for TFE3/TFEB alterations was performed if indicated. One case each (1 of 9, 11%) was classified as TFE3-rearranged and FH-deficient RCC. The majority were high grade (World Health Organization/International Society of Urologic Pathology grade 3: 8 of 9, 89%) or had features of aggressive disease, including hilar fat (6 of 9, 67%) and regional lymph node involvement (5 of 7, 71%). One low-grade 3.3-cm tumor with isolated PS involvement with a germline heterozygous FH p.Lys477dup alteration with retained FH, lack of increased S-(2-succino)-cysteine expression, BRAF V600E immunohistochemistry positivity, and lack of trisomy 7/17 on chromosomal microarray was identified, arguing against an FH-deficient and conventional PRCC. Our study shows that PS involvement by renal neoplasia with papillary architecture is a rare event. Aside from PRCC, it is important to note that these may include other aggressive and nonaggressive subtypes of renal neoplasia with papillary architecture. One case of isolated PS involvement by a low-grade, noninvasive tumor that we refer to as nephrogenic papillary neoplasm was identified. At present, there are insufficient data to stage such tumors as pT3a (AJCC, 8th edition), and additional studies are needed to address this question. •Pelvicalyceal system involvement by papillary renal cell carcinoma is a rare event.•Papillary renal neoplasia with pelvicalyceal system involvement is enriched for various subtypes of renal neoplasia.•In this study this included BRAF p.V600E mutated papillary renal neoplasia, FH-deficient RCC and TFE3-rearranged RCC.•BRAF p.V600E mutated papillary renal neoplasia lack gains of chromosomes 7/17 and may have unique morphologic features.•Additional studies are needed regarding staging papillary renal neoplasia with isolated pelvicalyceal system involvement.