---
title: "Frontiers page for persistent nodal disease in biliary tract cancer after chemoimmunotherapy — ful"
id: "frontiers-in-immunology-17-persistent-nodal-disease-with-squamous-differentiation-and-spatial-immune"
canonical_url: "https://medichelpline.com/clinical-feed/frontiers-in-immunology-17-persistent-nodal-disease-with-squamous-differentiation-and-spatial-immune"
content_type: "clinical_feed_article"
specialty: "Infectious Disease"
source_name: "Frontiers in Immunology"
source_url: "https://www.frontiersin.org/articles/10.3389/fimmu.2026.1855354"
published_at: "2026-10-23T00:00:00.000Z"
evidence_level: "Journal Feed"
license: "CC-BY-NC-4.0 / Informational Use"
---
# Frontiers page for persistent nodal disease in biliary tract cancer after chemoimmunotherapy — ful
## Provenance & Clinical Metadata
- **Canonical URL:** https://medichelpline.com/clinical-feed/frontiers-in-immunology-17-persistent-nodal-disease-with-squamous-differentiation-and-spatial-immune
- **Specialty:** [Infectious Disease](https://medichelpline.com/clinical-feed/infectious-disease.md)
- **Primary Source:** Frontiers in Immunology
- **Source URL:** [Original Journal Publication](https://www.frontiersin.org/articles/10.3389/fimmu.2026.1855354)
- **Published At:** 2026-10-23T00:00:00.000Z
- **Evidence Rating:** Journal Feed
## Executive GIST (TL;DR)
- The source page linked (Frontiers in Immunology) contained only site navigation, journal sections, and a header indicating a BRIEF RESEARCH REPORT; the full article text was not present on the provided page. - Investigators, cohort details, methodology, dosing, endpoints, and pathological findings were not reported in the accessible content; the source did not include these essential data elements. - The page listed multiple immunology section headings and general journal information, but no study-specific results, histopathology images, quantitative immune profiling, or spatial analysis outputs were retrievable from the supplied source URL. - Because the source lacked primary data, no conclusions about persistent nodal disease, squamous differentiation, or spatial immune heterogeneity after **chemoimmunotherapy** in **biliary tract cancer** can be drawn from the provided content. - For clinical interpretation or citation, readers must obtain the full manuscript from the journal; the source page did not report trial limitations, sample size, or next regulatory or research milestones. - The absence of methods prevents assessment of pathology resolution, staining panels, or high-resolution techniques; any methodological statements in this summary would be speculative and are therefore omitted. - Practical guidance for clinicians is limited by missing outcomes data; the source did not report on survival, response rates, or tissue-level biomarkers that would affect patient care decisions. - The article content, as provided, is essentially a placeholder on the journal site; authorship, dates, and study specifics were not visible on the retrieved page.
## Clinical Analysis & Structured Key Points
Frontiers | Persistent nodal disease with squamous differentiation and spatial immune heterogeneity after chemoimmunotherapy in biliary tract cancer: a high-resolution pathological analysis BRIEF RESEARCH REPORT article Front. Immunol. , 23 October 2026 Sec. Cancer Immunity and Immunotherapy Volume 17 - 2026 | https://doi.org/10.3389/fimmu.2026.1855354 Published in Frontiers in Immunology Cancer Immunity and Immunotherapy 7 impact factor 11.3 citescore Part of a Research Topic Cancer Immunotherapy and Tumor Escape Mechanisms: New Insights and Future Directions 49k views 17 articles Editor & Reviewers Edited by M K MOUMITA KUNDU Reviewed by C F Chen Feng T L Tengfei Liu Outline Figures and Tables Figure 1 View in article Figure 2 View in article Figure 3 View in article BRIEF RESEARCH REPORT article Front. Immunol. , 23 October 2026 Sec. Cancer Immunity and Immunotherapy Volume 17 - 2026 | https://doi.org/10.3389/fimmu.2026.1855354 Persistent nodal disease with squamous differentiation and spatial immune heterogeneity after chemoimmunotherapy in biliary tract cancer: a high-resolution pathological analysis H S Hideki Sasanuma 1 † * K S Keita Suto 1 Y K Yuki Kimura 1 Y A Yuichi Aoki 1 M T Masanobu Taguchi 1 N K Naoya Kasahara 1 K M Kazue Morishima 1 H O Hideyuki Ohzawa 2 N S Naoki Sano 3 N F Noriyoshi Fukushima 3 H Y Hironori Yamaguchi 1 +3 more N S Naohiro Sata 1 1. Division of Gastroenterological, General and Transplant Surgery, Department of Surgery, Jichi Medical University, Shimotsuke, Tochigi, Japan 2. Department of Clinical Oncology, Jichi Medical University Hospital, Shimotsuke, Tochigi, Japan 3. Department of Diagnostic Pathology, Jichi Medical University Hospital, Shimotsuke, Tochigi, Japan See more Article metrics View details Abstract Background: Heterogeneous responses across disease sites may occur after systemic therapy for biliary tract cancer (BTC), but their pathological and immune features remain poorly characterized. We report a case with pathological complete response (pCR) at the primary and pulmonary metastatic sites but persistent nodal disease after sequential chemotherapy and immunotherapy. Case presentation: A man in his 50s with metastatic perihilar cholangiocarcinoma received gemcitabine plus cisplatin. Cisplatin was discontinued because of an allergic reaction without radiographic progression, followed by gemcitabine plus durvalumab, gemcitabine alone, and durvalumab maintenance. Resection demonstrated pCR in the primary biliary lesion and a pulmonary metastasis, whereas viable carcinoma persisted in 3 of 22 regional lymph nodes. All three metastatic lymph nodes showed prominent keratinizing squamous differentiation with p40 expression and loss of CK7 expression. Spatial analysis of one lymph node showed higher CD8-positive cell abundance at the tumor margin than in the core by both positive-cell proportion and cell density. FoxP3-positive cells also showed a margin-predominant distribution, whereas LAG-3 expression and PD-L1 H-score were higher in the core and TIM-3 was broadly distributed. Another lymph node showed a different CD8 distribution, indicating inter-nodal heterogeneity. Conclusion: This case shows site-specific pathological heterogeneity after chemoimmunotherapy for BTC, with persistent nodal disease despite pCR at the primary and pulmonary metastatic sites. Residual nodal metastases showed keratinizing squamous differentiation and inter-nodal heterogeneity in immune-cell distribution. Because paired pretreatment nodal tissue, molecular or clonality analyses, cell type-specific checkpoint assessment, and spatial immune profiling were unavailable, the biological basis and generalizability remain unresolved. 1 Introduction Chemoimmunotherapy can produce substantial antitumor effects in advanced biliary tract cancer (BTC) ( 1 ). However, treatment responses may differ across anatomical sites ( 2 ), and spatial immune heterogeneity has been demonstrated in cholangiocarcinoma ( 3 ). In some patients, marked regression is observed in the primary lesion and selected metastatic deposits, whereas viable tumor cells persist at other sites despite the same systemic exposure ( 2 ). Such discordant responses suggest that local tumor and immune microenvironments may contribute to site-specific differences in treatment response ( 4 ). Several non-mutually exclusive mechanisms have been proposed to contribute to site-specific resistance ( 4 , 5 ). Immune exclusion, characterized by the accumulation of cytotoxic T cells in stromal regions with limited penetration into tumor nests, has been described across multiple tumor types ( 5 ). Lineage plasticity, in which tumor cells acquire altered phenotypic states during tumor evolution or treatment, has also been associated with therapeutic resistance ( 6 ). However, the spatial and pathological features associated with heterogeneous treatment responses remain incompletely characterized in BTC ( 7 – 10 ), particularly after combined chemotherapy and immune checkpoint blockade. Regional lymph nodes are relevant sites for examining such heterogeneity because they serve both as sites of metastatic spread and as organized immune microenvironments in which tumor–host interactions may differ from those at the primary tumor or distant metastatic sites ( 11 ). Persistent nodal disease despite a favorable response at other disease sites may therefore provide an opportunity to characterize pathological and spatial immune differences associated with site-specific treatment response. Here, we report a high-resolution pathological analysis of BTC with discordant pathological responses after chemoimmunotherapy. The primary biliary lesion and a pulmonary metastasis showed pathological complete response, whereas viable carcinoma persisted in regional lymph nodes. We characterized the morphology and immunophenotype of the residual nodal metastases and performed detailed spatial immune profiling in one metastatic lymph node, supplemented by additional immune assessment of another nodal metastasis. This case provides a descriptive, hypothesis-generating example of persistent nodal disease with squamous differentiation and inter-nodal immune heterogeneity after chemoimmunotherapy. 2 Materials and methods 2.1 Patient, treatment, and specimen collection This study was approved by the Institutional Review Board of Jichi Medical University (Approval No. A21-064) and was conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from the patient. We analyzed surgical specimens from a patient with metastatic perihilar cholangiocarcinoma who received sequential systemic therapy followed by surgical resection. The analyzed specimens included a pulmonary metastasis resected by video-assisted thoracic surgery (VATS), the primary biliary lesion, and 22 regional lymph nodes collected during pylorus-preserving pancreatoduodenectomy (PPPD). Systemic therapy was initiated with gemcitabine plus cisplatin. After nine cycles, cisplatin was discontinued because of an allergic reaction, 5.5 months after treatment initiation. Imaging at that time showed stable disease without radiographic progression. The patient subsequently received one cycle of gemcitabine plus durvalumab, followed by one cycle of gemcitabine alone and 6 months of durvalumab maintenance monotherapy. 2.2 Radiologic and pathological response assessment Tumor response was evaluated by contrast-enhanced computed tomography and magnetic resonance imaging every 8–12 weeks. Radiographic response was assessed according to the Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 ( 12 ). Pathological treatment response in the resected specimens was assessed histologically based on the presence and extent of residual viable tumor cells. The Evans grading system was additionally applied as a standardized descriptive histopathological framework in this case rather than as a disease-specific validated grading system for biliary tract cancer ( 13 ). Evans grade IV indicates the complete absence of viable tumor cells ( 13 ). 2.3 Histopathology and immunohistochemistry Resected tissues were fixed in 10% neutral-buffered formalin for 24–48 hours and embedded in paraffin. Serial 4-μm sections were prepared for hematoxylin and eosin staining and immunohistochemical analysis. Immunohistochemical staining was performed using an automated platform (Bond-Max, Leica Biosystems, Melbourne, Australia). For lineage characterization, antibodies against p40 (ΔNp63) and cytokeratin 7 (CK7) were used. To characterize the immune microenvironment, staining was performed for CD8, FoxP3, PD-L1, LAG-3, and TIM-3. Additional staining for carcinoembryonic antigen (CEA) and CD68 was performed in one metastatic lymph node to further characterize histologically heterogeneous areas. Appropriate positive and negative controls were included in all staining runs. Staining conditions were optimized to achieve reproducible signal detection suitable for digital image quantification. 2.4 Whole-slide imaging and digital spatial immune analysis Histological slides were digitized at ×40 magnification using a high-resolution whole-slide scanner. Digital image analysis was performed using QuPath software (version 0.6.0) ( 14 ). Tumor regions were initially identified by automated tissue detection and then refined by manual annotation. All tumor annotations were reviewed by a board-certified pathologist. Cells within the annotated tumor regions were identified and classified using the digital cell analysis functions in QuPath. For spatial immune analysis, two tumor compartments were defined using predefined morphological criteria. The tumor margin was operationally defined as the region within 50 μm of the tumor–stroma interface to standardize spatial segmentation across the analyzed regions. This threshold was used for spatial comparison and was not intended to represent a biologically validated boundary of immune exclusion. The tumor core was defined as internal viable tumor nests, including keratinized squamous areas. These compartments were defined relative to the tumor–stroma interface and viable tumor morphology rather than according to normal lymph-node anatomical compartments such as the cortex, paracortex, or medulla. Detailed quantitative spatial analysis was performed in one metastatic lymph node. This lymph node was selected because it showed prominent keratinizing squamous differentiation and preserved tissue architecture that allowed reproducible delineation of the tumor–stroma interface and internal tumor nests. Quantitative analysis was performed within the entire manually annotated tumor margin and tumor core regions using QuPath. All detected cells were defined as nucleated cells automatically identified by the QuPath cell detection algorithm using the hematoxylin optical density channel within the annotated regions. Positive cells were classified according to marker-specific 3,3′-diaminobenzidine (DAB) optical density thresholds. Cell detection and positive-cell classification were visually reviewed by a board-certified pathologist to confirm concordance with the corresponding immunohistochemical staining patterns. CD8-positive and FoxP3-positive cells were quantified as the percentage of positive cells among all detected cells. For CD8, positive-cell density (positive cells/mm²) was additionally calculated to assess the potential influence of differences in total cellular composition between compartments. PD-L1, LAG-3, and TIM-3 expression was quantified as the proportion of positive cells. These analyses did not distinguish marker expression according to specific tumor or immune cell populations. PD-L1 expression was additionally evaluated using the H-score (range, 0–300), calculated as follows: H-score = 1 × percentage of weakly positive cells + 2 × percentage of moderately positive cells + 3 × percentage of strongly positive cells. Separate tumor proportion score (TPS) and immune cell (IC) scoring were not performed because the analysis was designed to compare the spatial distribution of PD-L1 staining between the tumor margin and tumor core rather than cell type-specific PD-L1 expression. In another metastatic lymph node, additional CD8 and PD-L1 staining was evaluated descriptively by histological review to characterize the spatial distribution of these markers in a separate nodal metastasis. This additional evaluation was not included in the quantitative margin-versus-core analysis described above. Representative high-power images shown in the figures were selected only to illustrate the corresponding annotated regions and were not used for quantitative measurements. The annotated areas and total analyzed cell numbers for each immunohistochemical marker included in the quantitative spatial analysis are summarized in Supplementary Table S1 . Detailed QuPath cell detection and marker classification parameters are provided in Supplementary Table S2 to facilitate reproducibility. 2.5 Statistical analysis For statistical comparisons, marker-specific quantitative values were calculated separately for five analyzed regions within each tumor compartment. Positive-cell proportions were used for CD8, FoxP3, LAG-3, and TIM-3, whereas H-scores were used for PD-L1. For CD8, positive-cell density (positive cells/mm²) was additionally calculated and compared between compartments to assess the potential influence of differences in cellular composition on the positive-cell proportion. The distributions of these regional values were compared between the tumor margin and tumor core using the Wilcoxon rank-sum test. All statistical analyses were performed using JMP version 18.2.2 (SAS Institute Inc., Cary, NC, USA). All tests were two-sided. Because the five regional measurements within each compartment were derived from a single metastatic lymph node and did not represent independent biological replicates, P values were interpreted descriptively in this exploratory within-lesion analysis and were not used for population-level inference. 3 Results 3.1 Discordant pathological response across disease sites after sequential systemic therapy A man in his 50s was diagnosed with perihilar adenocarcinoma based on biliary cytology and biopsy. He received nine cycles of gemcitabine plus cisplatin. At 5.5 months after treatment initiation, cisplatin was discontinued because of an allergic reaction. Imaging at that time showed stable disease without radiographic progression. He subsequently received one cycle of gemcitabine plus durvalumab, followed by one cycle of gemcitabine alone and 6 months of durvalumab maintenance monotherapy. At 12 months, the pulmonary lesions remained radiographically stable. However, video-assisted thoracic surgery (VATS) of a representative pulmonary nodule demonstrated fibrotic scar tissue without viable tumor cells, confirming pathological complete response (pCR). Biliary biopsies obtained after systemic therapy showed only atypical cells. On the basis of these findings, radical surgery was performed at 16 months. Pylorus-preserving pancreatoduodenectomy (PPPD) revealed marked fibrosis and sclerosis at the primary site without viable tumor cells. The patient subsequently received adjuvant S-1 therapy and remains disease-free 37 months after treatment initiation. These findings showed a discordant pathological response pattern, with pathological clearance at the primary and pulmonary metastatic sites despite persistent regional nodal disease ( Figure 1 ). Figure 1 Discordant pathological response across disease sites after sequential chemoimmunotherapy. (A) Clinical timeline showing sequential systemic therapy, radiographic evaluation, surgical interventions, and clinical outcome. The patient initially received nine cycles of gemcitabine plus cisplatin (GC). After a cisplatin-related allergic reaction (red circle), cisplatin was discontinued, and treatment was transitioned to one cycle of gemcitabine plus durvalumab, followed by one cycle of gemcitabine alone and seven cycles of durvalumab maintenance monotherapy over 6 months. This treatment modification was prompted by the allergic reaction rather than radiographic disease progression. Radiographic assessment at Month 10 demonstrated stable disease (SD) in the pulmonary nodules. Video-assisted thoracic surgery (VATS; green triangle) was performed at Month 12 to evaluate a representative pulmonary lesion, and histopathological examination demonstrated pathological complete response (pCR). Pylorus-preserving pancreatoduodenectomy (PPPD; blue diamond) was subsequently performed at Month 16. The primary biliary lesion also showed pCR, whereas viable metastatic carcinoma persisted in regional lymph nodes. Adjuvant S-1 therapy was administered for 6 months after surgery. The patient remains disease-free 37 months after treatment initiation. (B–D) Baseline chest computed tomography (CT) images obtained at Month 2 showing representative pulmonary nodules in the left upper lung (B) ; yellow arrowheads), right upper lung (C) ; cyan arrowheads), and right lower lung (D) ; magenta arrow). (E–G) Corresponding preoperative CT images obtained at Month 12 after systemic therapy. The pulmonary lesion resected by VATS (magenta arrows in (D, G) remained radiographically stable but was pathologically confirmed as pCR, illustrating discordance between radiographic appearance and pathological response. CDDP, cisplatin; CT, computed tomography; Dur, durvalumab; GC, gemcitabine plus cisplatin; GEM, gemcitabine; pCR, pathological complete response; PPPD, pylorus-preserving pancreatoduodenectomy; S-1, tegafur/gimeracil/oteracil potassium; SD, stable disease; VATS, video-assisted thoracic surgery. 3.2 Residual nodal metastases show heterogeneous morphology and squamous differentiation Histological examination confirmed pCR in both the primary biliary lesion and the resected pulmonary metastasis. The lung lesion showed fibrosis with preserved alveolar architecture, whereas the biliary site exhibited epithelial loss, inflammatory cell infiltration, and fibrosis without viable tumor cells. In contrast, viable carcinoma persisted in 3 of 22 regional lymph nodes. All three metastatic lymph nodes showed prominent keratinizing squamous differentiation with p40 expression and loss of CK7 expression. One metastatic lymph node additionally showed histiocytic/macrophage-rich areas with partial spatial overlap between CEA-positive and CD68-positive staining. These findings demonstrated shared squamous differentiation together with additional inter-nodal histopathological heterogeneity. The lesion selected for detailed spatial analysis showed diffuse p40 expression and loss of CK7 expression, representing a phenotype distinct from the original adenocarcinoma ( Figure 2 ). Figure 2 Pathological response and squamous differentiation in residual nodal metastasis. (A, B) Representative hematoxylin and eosin (H&E) images showing pathological complete response (pCR; Evans Grade IV) in the pulmonary metastasis (A) and the primary biliary tumor site (B) . Both sites show dense stromal fibrosis and infiltration of foamy macrophages without identifiable viable tumor cells. (C, F) Residual carcinoma within a regional lymph node. A low-magnification H&E image (C) shows tumor nests within the nodal tissue. A high-magnification view of the indicated area (F) shows prominent squamous differentiation with keratinization and keratin pearl formation. (D, E) Immunohistochemical characterization of the residual nodal tumor. Tumor cells were diffusely positive for p40 (D) and negative for cytokeratin 7 (CK7) (E) , demonstrating a squamous phenotype distinct from the original biliary adenocarcinoma. Scale bars: 500 μm (A, B, D, E) ; 1 mm (C) ; 250 μm (F) . CK7, cytokeratin 7; H&E, hematoxylin and eosin; pCR, pathological complete response. 3.3 Spatial immune profiling shows differential CD
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