Papillary renal cell carcinoma: a single institutional study of 199 cases addressing classification, clinicopathologic and molecular features, and treatment outcome

Autor: Murugan, Paari, Jia, Liwei, Dinatale, Renzo G., Assel, Melissa, Benfante, Nicole, Al-Ahmadie, Hikmat A., Fine, Samson W., Gopalan, Anuradha, Sarungbam, Judy, Sirintrapun, S. Joseph, Hakimi, A. Ari, Russo, Paul, Chen, Ying-Bei, Tickoo, Satish K., Reuter, Victor E.
Zdroj: Modern Pathology; June 2022, Vol. 35 Issue: 6 p825-835, 11p
Abstrakt: The morphologic spectrum of type 1 papillary renal cell carcinoma (PRCC) is not well-defined, since a significant proportion of cases have mixed type 1 and 2 histology. We analyzed 199 cases of PRCC with any (even if focal) type 1 features, with a median follow-up of 12 years, to identify clinicopathological features associated with outcome. Ninety-five tumors (48%) of the cohort contained some type 2 component (median amount: 25%; IQR: 10%, 70%). As a group they showed high rates of progression-free (PFS) and cancer-specific survival (CSS). Tumor size, mitotic rate, lymphovascular invasion, sarcomatoid differentiation, sheet-like architecture, and lack of tumor circumscription were significantly associated with CSS (p≤ 0.015) on univariate analysis. While predominant WHO/ISUP nucleolar grade was associated with PFS (p= 0.013) and CSS (p= 0.030), the presence of non-predominant (<50%) nucleolar grade did not show association with outcome (p= 0.7). PFS and CSS showed no significant association with the presence or the amount of type 2 morphology. We compared the molecular alterations in paired type 1 and type 2 areas in a subset of 22 cases with mixed type 1 and 2 features and identified 12 recurrently mutated genes including TERT, ARID1A, KDM6A, KMT2D, NFE2L2, MET, APC, and TP53. Among 78 detected somatic mutations, 61 (78%) were shared between the paired type 1 and type 2 areas. Copy number alterations, including chromosome 7 and 17 gains, were similar between type 1 and 2 areas. These findings support that type 2 features in a PRCC with mixed histology represent either morphologic variance or clonal evolution. Our study underscores the notion that PRCC with any classic type 1 regions is best considered as type 1 PRCC and assigned the appropriate WHO/ISUP nucleolar grade. It provides additional evidence that type 2 PRCC as a separate category should be re-assessed and likely needs to be abandoned.
Databáze: Supplemental Index
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