Papillary Renal Cell Carcinoma With Microcystic Architecture Is Strongly Associated With Extrarenal Invasion and Metastatic Disease, The American Journal of Surgical Pathology: March 2022 – Volume 46 – Issue 3 – p 392-403 doi: 10.1097\/PAS.0000000000001802<\/p>\n
FREE LINK<\/strong> https:\/\/journals.lww.com\/ajsp\/Fulltext\/2022\/03000\/Papillary_Renal_Neoplasm_With_Reverse_Polarity_Is.5.aspx<\/p>\n Chan, Emily MD*; Stohr, Bradley A. MD, PhD*; Butler, Robert S. MS†; Cox, Roni M. MD‡; Myles, Jonathan L. MD‡; Nguyen, Jane K. MD, PhD‡; Przybycin, Christopher G. MD‡; Reynolds, Jordan P. MD‡; Williamson, Sean R. MD‡; McKenney, Jesse K. MD‡<\/p>\n Précis<\/u><\/p>\n Over the last few years, scientific research has reshaped the histological landscape of the second most common renal cell cancer, namely papillary renal cell carcinoma (PRCC). Accordingly, the novel WHO 2022 classification for renal tumors overcomes the traditional subtyping into type 1 and type 2 PRCC, encompassing a large spectrum of distinct architectural features, which include the conventional “type 1” papillary and tubular structures, along with solid, biphasic\/squamoid, Warthin-like, and reverse polarity patterns (the last one referred to as “papillary neoplasm with reverse polarity”), among the others. Overall, PRCC is still regarded as a tumor with better clinical outcome than clear cell renal cell carcinoma (CCRCC).<\/p>\n In this original 3-arm study, Chan et al. identified the presence of microcystic architecture in 67 out of 102 PRCCs, most of them being high-stage pT2a to pT3b tumors. Traditionally, these cases would be have been labeled type 1 PRCC. Microcysts were defined as “variably sized cysts lined by neoplastic epithelial cells and containing the papillary tumor”. Molecular analysis through capture-based next-generation DNA sequencing was performed on 15 cases, revealing that the majority of such tumors harbored recurrent PRCC-related chromosomal alterations, particularly multiple gains of chromosomes 7, 16, and 17. Microcystic architecture was often combined with other “unfavorable” patterns (namely, micropapillary, solid, and hobnail), and was the most frequent and reproducible among them. Solid and hobnail features, as well as the presence of microcysts at the tumor-stromal interface, were significantly associated with adverse outcome, with hazard ratios as high as 6.3, 5.3, and 4.2, respectively.<\/p>\n <\/p>\n Comment<\/p>\n This study stemmed from the authors’ anecdotal observation that microcystic architecture in PRCC is associated with more aggressive disease. Interestingly, microcystic pattern is not mentioned among the pathological features of PRCC in the WHO classifications for renal tumors over the last 40 years. ‘Microcystic structures containing clumps of tumor cells’, reminiscent to those identified in this study, have been reported in the early 1981 blue book entitled “Histological typing of kidney tumors”, as part of the wide histological landscape of the comprehensive entity referred to as “renal cell carcinoma”. Evidence from the literature taught us that PRCC is rather a group of entities, than a single one, with mostly overlapping, yet variable morphological, immunohistochemical, and molecular features. PRCC is defined after ruling out other, much less frequent, old and new histotypes, including FH-deficient RCC, MiT family gene-rearranged RCC, eosinophilic solid and cystic RCC, and collecting duct RCC, the latter two occasionally presenting with microcystic features as well. Nevertheless, the main finding in this study was the prognostic role and practical value of the microcystic architecture at the invasion front of the tumor, along its high interobserver agreement (k score=0.79). As a side note, in this cohort of mostly high-stage PRCCs, a k score of 0.16 was reported for ISUP nucleolar grade, which was the one histological feature yielding the lowest agreement among 6 expert GU pathologists. Since grade is still regarded as a powerful prognostic factor in RCC, this finding deserves more focused research, particularly in view of the recent attempts to standardize its reproducibility in the digital pathology setting. With its meaningful observations, this study adds to the idea that the subtyping of this tumor into type 1 and type 2 is no longer clinically relevant. Furthermore, it endorses the high complexity of the entity known as PRCC, giving ground to further research on the molecular profiling and clinical correlations of its distinct morphological patterns.<\/p>\n<\/body><\/html>\n","protected":false},"excerpt":{"rendered":" Papillary Renal Cell Carcinoma With Microcystic Architecture Is Strongly Associated With Extrarenal Invasion and Metastatic Disease, The American Journal of Surgical Pathology: March 2022 – Volume 46 – Issue 3 – p 392-403 doi: 10.1097\/PAS.0000000000001802 FREE LINK https:\/\/journals.lww.com\/ajsp\/Fulltext\/2022\/03000\/Papillary_Renal_Neoplasm_With_Reverse_Polarity_Is.5.aspx Chan, Emily MD*; Stohr, Bradley A. MD, PhD*; Butler, Robert S. MS†; Cox, Roni M. MD‡; Myles, … Continue reading FIRST QUARTER OF 2022<\/span>