Noninvasive low-grade papillary urothelial carcinoma with degenerative nuclear atypia: a grading pitfall

Pathologic assessment of hepatocellular carcinoma in the era of immunotherapy: a narrative review

Background and Objective

Immune checkpoint inhibitor (ICI)-based therapy has achieved impressive success in various cancer types. Several ICIs have been unprecedentedly approved as the treatment regimens for advanced hepatocellular carcinoma (HCC) in recent decade. Meanwhile, numerous clinical trials are being performed to exploit more ICIs into initially unresectable HCC and postoperative HCC to expectantly induce adequate tumor downstaging for further resection or implement adjuvant treatment for relapse-free survival, respectively. In this review, we aim to summarize some pragmatic histomorphologic, immunohistochemical, and molecular pathologic parameters which promisingly indicate the response of neoadjuvant/conversion ICI-related therapy and predict the efficacy of adjuvant/therapeutic ICI-related therapy for HCC.

Methods

We searched PubMed using the terms hepatocellular carcinoma, immunotherapy, immune checkpoint inhibitor, immune checkpoint blockade, conversion therapy, neoadjuvant therapy, adjuvant therapy, biomarker, pathologic evaluation, pathologic assessment till February 2023.

Key Content and Findings

Although there is no consensus regarding the pathologic evaluation of relevant HCC specimens, it is encouraging that a few of studies have concentrated on this field, and moreover, the methods and parameters noted on other cancer types are also worthy of reference. For the pathologic assessment of HCC specimens underwent immunotherapy, a suitable sampling scheme, identifying immunotherapy-related pathologic response, and quantification of pathologic response rate should be emphasized. For the patients of HCC who are scheduled to receive immunotherapy, tumor-infiltrating lymphocyte, intratumoral tertiary lymphoid structure, programmed cell death ligand 1, Wnt/β-catenin, microsatellite instability and mismatch repair, tumor mutational burden and tumor neoantigen, as well as some other signaling pathways are the potential predictive biomarkers of treatment response of ICI.

Conclusions

The management of HCC in the era of immunotherapy arises a brand-new pathological challenge that is to provide an immunotherapy-related diagnostic report. Albeit many related researches are preclinical or insufficient, they may tremendously alter the immunotherapy strategy of HCC in future.

Utility of GATA-3 and Cytokeratin 5/6 Immunostains in Separating Condyloma Acuminatum Arising in the Urinary Tract From Non-Invasive Papillary Urothelial Carcinoma

Background Condyloma acuminatum is a squamous epithelial lesion which uncommonly involves the urinary tract. In this location, non-invasive papillary urothelial carcinoma constitutes one of the main differential diagnoses with significant prognostic and therapeutic implications. To date, no ancillary immunohistochemical stain has been described to differentiate these two entities. We assess the utility of cytokeratin 5/6 (CK5/6) and GATA-3 immunohistochemistry in distinguishing condyloma acuminatum from non-invasive papillary urothelial carcinoma. Design We reviewed 9 condylomata acuminata involving the urinary tract, 12 low-grade and 8 high-grade non-invasive papillary urothelial carcinomas. CK5/6 immunostaining was performed in all cases. GATA-3 immunostaining and low-risk human papilloma virus (HPV) chromogenic in situ hybridization was performed in all condyloma cases and 2 urothelial carcinomas with squamous differentiation. Results 8/9 condylomata acuminata were positive for low-risk HPV. All condylomata acuminata exhibited strong full-thickness cytoplasmic staining for CK5/6. In 10 of 12 low-grade non-invasive papillary urothelial carcinomas, CK5/6 expression was continuous and limited to the basal cell layer, while it was patchy and limited to the basal cell layer in all 8 high-grade non-invasive papillary urothelial carcinomas. Two low-grade non-invasive papillary urothelial carcinomas showed focal full-thickness CK5/6 expression in the areas of squamous differentiation. These 2 cases were negative for low-risk HPV. GATA-3 immunostaining was positive in all condylomata acuminata. Conclusions CK5/6 immunostaining is a useful and simple tool that can help separate low-grade and high-grade non-invasive papillary urothelial carcinomas from condyloma acuminatum involving the urothelium-lined organs. GATA-3 has no discriminatory role between condyloma acuminatum and papillary urothelial carcinomas.