Basile Tessier‐Cloutier

Prognostic values of molecular subtypes and SWI/SNF protein expression in de‐differentiated/undifferentiated endometrial carcinoma

AimsClassification and risk stratification of endometrial carcinoma (EC) has transitioned from histopathological features to molecular classification, e.g. the ProMisE classifier, identifying four prognostic subtypes: POLE mutant (POLEmut) with almost no recurrence or disease‐specific death events, mismatch repair deficient (MMRd) and no specific molecular profile (NSMP), with intermediate outcome and p53 abnormal (p53abn) with poor outcomes. However, the applicability of molecular classification is unclear in rare but aggressive histotypes of EC, e.g. de‐differentiated and undifferentiated endometrial cancers (DD/UDEC). Here, we aim to assembled a cohort of DD/UDEC from a single institution and analysed the prognostic significance of ProMisE molecular subtypes and the expression of SWItch/sucrose non‐fermentable (SWI/SNF) chromatin remodelling complex members, previously implicated in the pathogenesis of DD/UDEC.Methods and resultsWe accrued 88 DD/UDEC cases, assessed POLE status by Sanger sequencing and performed immunohistochemistry for p53, mismatch repair and SWI/SNF proteins on the tissue microarrays assembled. Assignment of molecular subtypes was possible in 80 tumours; POLE sequencing failed in the remaining eight cases. There were 12 (15%) POLEmut, 44 (55%) MMRd, 14 (17.5%) p53abn and 10 (12.5%) NSMP DD/UDEC. POLEmut DD/UDECs had excellent outcomes, but the other three molecular subtypes all had poor outcomes, with no significant differences among them. The loss of one or more SWI/SNF proteins [AT‐rich interactive domain‐containing protein 1A (ARID1A), ARID1B, SWI/SNF‐related, matrix‐associated, actin‐dependent regulator of chromatin, subfamily A, member 4 (SMARCA4), SMARCA2], observed in 66% (55 of 83) cases, was not of prognostic significance.ConclusionsThese results indicate that all molecular subtypes of DD/UDEC except POLEmut behave in an aggressive fashion. Further study is needed to determine whether these molecular alterations can be targeted with adjuvant therapy, in order to improve outcomes of patients with DD/UDEC.

Dedifferentiated and Undifferentiated Ovarian Carcinoma: An Aggressive and Molecularly Distinct Ovarian Tumor Characterized by Frequent SWI/SNF Complex Inactivation

Dedifferentiated and undifferentiated ovarian carcinomas (DDOC/UDOC) are rare neoplasms defined by the presence of an undifferentiated carcinoma. In this study, we detailed the clinical, pathological, immunohistochemical, and molecular features of a series of DDOC/UDOC. We collected a multi-institutional cohort of 23 DDOC/UDOC and performed immunohistochemistry for core switch/sucrose nonfermentable (SWI/SNF) complex proteins (ARID1A, ARID1B, SMARCA4, and SMARCB1), mismatch repair (MMR) proteins, and p53. Array-based genome-wide DNA methylation and copy number variation analyses were performed on a subset of cases with comparison made to a previously reported cohort of undifferentiated endometrial carcinoma (UDEC), small cell carcinoma of the ovary, hypercalcemic type (SCCOHT), and tubo-ovarian high-grade serous carcinoma (HGSC). The age of all 23 patients with DDOC/UDOC ranged between 22 and 71 years (with an average age of 50 years), and a majority of them presented with extraovarian disease (16/23). Clinical follow-up was available for 19 patients. Except for 2 patients, the remaining 17 patients died from disease, with rapid disease progression resulting in mortality within a year in stage II-IV settings (median disease-specific survival of 3 months). Eighteen of 22 cases with interpretable immunohistochemistry results showed loss of expression of core SWI/SNF protein(s) that are expected to result in SWI/SNF complex inactivation as 10 exhibited coloss of ARID1A and ARID1B, 7 loss of SMARCA4, and 1 loss of SMARCB1. Six of 23 cases were MMR-deficient. Two of 20 cases exhibited mutation-type p53 immunoreactivity. Methylation profiles showed coclustering of DDOC/UDOC with UDEC, which collectively were distinct from SCCOHT and HGSC. However, DDOC/UDOC showed an intermediate degree of copy number variation, which was slightly greater, compared with SCCOHT but much less compared with HGSC. Overall, DDOC/UDOC, like its endometrial counterpart, is highly aggressive and is characterized by frequent inactivation of core SWI/SNF complex proteins and MMR deficiency. Its molecular profile overlaps with UDEC while being distinct from SCCOHT and HGSC.

Mesonephric‐like adenocarcinoma harbours characteristic copy number variations and a distinct DNA methylation signature closely related to mesonephric adenocarcinoma of the cervix

Abstract Mesonephric‐like adenocarcinoma (MLA) of the female genital tract is an uncommon histotype that can arise in both the endometrium and the ovary. The exact cell of origin and histogenesis currently remain unknown. Here, we investigated whole genome DNA methylation patterns and copy number variations (CNVs) in a series of MLAs in the context of a large cohort of various gynaecological carcinoma types. CNV analysis of 19 MLAs uncovered gains of chromosomes 1q (18/19, 95%), 10 (15/19, 79%), 12 (14/19, 74%), and 2 (10/19, 53%), as well as loss of chromosome 1p (7/19, 37%). Gains of chromosomes 1q, 10, and 12 were also identified in the majority of mesonephric adenocarcinomas of the uterine cervix (MAs) as well as subsets of endometrioid carcinomas (ECs) and low‐grade serous carcinomas of the ovary (LGSCs) but only in a minority of serous carcinomas of the uterine corpus (USCs), clear cell carcinomas (CCCs), and tubo‐ovarian high‐grade serous carcinomas (HGSCs). While losses of chromosome 1p together with gains of chromosome 1q were also identified in both MA and LGSC, gains of chromosome 2 were almost exclusively identified in MLA and MA. Unsupervised hierarchical clustering and t‐SNE analysis of DNA methylation data (Illumina EPIC array) identified a co‐clustering for MLAs and MAs, which was distinct from clusters of ECs, USCs, CCCs, LGSCs, and HGSCs. Group‐wise comparisons confirmed a close epigenetic relationship between MLA and MA. These findings, in conjunction with the established histological and immunophenotypical overlap, suggest bona fide mesonephric differentiation, and support a more precise terminology of mesonephric‐type adenocarcinoma instead of MLA in these tumours. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Endometrial neuroendocrine carcinoma and undifferentiated carcinoma are distinct entities with overlap in neuroendocrine marker expression

AimsDedifferentiated endometrial carcinomas (DDECs)/undifferentiated endometrial carcinomas (UDECs) frequently harbour genomic activation of switch/sucrose non‐fermentable (SWI/SNF)‐complex proteins, and can show histological overlap with neuroendocrine carcinoma (NEC). The aim of this study was to compare the extent of the expression of neuroendocrine markers, SWI/SNF proteins and mismatch repair (MMR) proteins in DDEC/UDEC and NEC.Methods and resultsThe extent of expression of synaptophysin, chromogranin, CD56, ARID1A, ARID1B, SMARCA4, SMARCB1 and MMR proteins was evaluated by immunohistochemistry on 44 SWI/SNF‐deficient DDECs/UDECs and 15 NECs. Thirty‐three of 44 (75%) DDECs/UDECs showed expression of at least one neuroendocrine marker, with 18 of 44 (41%) expressing two or more neuroendocrine markers, whereas all 15 NECs showed expression of at least one neuroendocrine marker, with 14 of 15 (93%) expressing two or more neuroendocrine markers. Neuroendocrine marker expression in DDECs/UDECs was typically focal when present, with average extents of 17%, 4% and 8% for synaptophysin, chromogranin and CD56 in the positive cases, respectively, in contrast to 73%, 40% and 62% in the positive NEC cases, respectively. All 15 NECs showed intact expression of SWI/SNF‐complex proteins, except for one that showed isolated loss of ARID1A. Thirty‐eight of 44 DDECs/UDECs were MMR‐abnormal (34 with loss of MLH1 and PMS2, and four with loss of PMS2 alone), whereas all NECs retained MMR protein expression.ConclusionsOur study demonstrates frequent but typically focal neuroendocrine marker expression in SWI/SNF‐deficient DDECs/UDECs, whereas NECs typically express two or more neuroendocrine markers, with diffuse expression of at least one marker. ARID1B, SMARCA4 and SMARCB1 immunohistochemistry can be used to aid in the differentiation between DDEC/UDEC and NEC.

Cellular context determines DNA methylation profiles in SWI/SNF‐deficient cancers of the gynecologic tract

AbstractSWI/SNF (SWItch/Sucrose Non‐Fermentable) complex deficiency has been reported in a wide variety of cancers and is often associated with an undifferentiated phenotype. In the gynecologic tract SWI/SNF‐deficient cancers are diagnostically challenging and little is known about their cellular origins. Here we show that undifferentiated endometrial carcinoma (UDEC), SMARCA4‐deficient uterine sarcoma (SDUS), and ovarian small cell carcinoma, hypercalcemic type (SCCOHT) harbor distinct DNA methylation signatures despite shared morphology and SWI/SNF inactivation. Our results indicate that the cellular context is an important determinant of the epigenetic landscape, even in the setting of core SWI/SNF deficiency, and therefore methylation profiling may represent a useful diagnostic tool in undifferentiated, SWI/SNF‐deficient cancers. Furthermore, applying copy number analyses and group‐wise differential methylation analyses including endometrioid endometrial carcinomas and extracranial malignant rhabdoid tumors, we uncover analogous molecular features in SDUS and SCCOHT in contrast to UDEC. These results suggest that SDUS and SCCOHT represent chromosomally stable SWI/SNF‐deficient cancers of the gynecologic tract, which are within the broader spectrum of malignant rhabdoid tumors. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

SWI/SNF‐deficiency defines highly aggressive undifferentiated endometrial carcinoma

AbstractDedifferentiated/undifferentiated endometrial carcinoma (DDEC/UEC) is an endometrial cancer characterized by the presence of histologically undifferentiated carcinoma. Genomic inactivation of core switch/sucrose nonfermentable (SWI/SNF) complex proteins was recently identified in approximately two‐thirds of DDEC/UEC. The aim of this study was to delineate the clinical behavior of SWI/SNF‐deficient DDEC/UEC in comparison to SWI/SNF‐intact DDEC/UEC. The study cohort consisted of 56 SWI/SNF‐deficient DDEC/UEC (2 POLE‐mutated), which showed either SMARCA4 (BRG1) loss, ARID1A/1B co‐loss, or SMARCB1 (INI1) loss in the undifferentiated tumor, and 26 SWI/SNF‐intact DDEC/UEC (4 POLE‐mutated). The average age at diagnosis was 61 years for patients with SWI/SNF‐deficient tumors and 64 years for SWI/SNF‐intact tumors. Mismatch repair (MMR) protein deficiency was seen in 66% of SWI/SNF‐deficient and 50% of SWI/SNF‐intact tumors. At initial presentation, 55% of patients with SWI/SNF‐deficient tumors had extrauterine disease spread in contrast to 38% of patients with SWI/SNF‐intact tumors. The 2‐year disease specific survival (DSS) for stages I and II disease was 65% for SWI/SNF deficient tumors relative to 100% for SWI/SNF‐intact tumors (p = 0.042). For patients with stages III and IV disease, the median survival was 4 months for SWI/SNF‐deficient tumors compared to 36 months for SWI/SNF‐intact tumors (p = 0.0003). All six patients with POLE‐mutated tumors, including one with stage IV SWI/SNF‐deficient tumor were alive with no evidence of disease. Among the patients with advanced stage SWI/SNF‐deficient tumors, 68% (21 of 31) received adjuvant or neoadjuvant chemotherapy (platinum/taxane‐based) and all except the patient with a POLE‐mutated tumor (20 of 21) experienced disease progression either during chemotherapy or within 4 months after its completion. These findings show that core SWI/SNF‐deficiency defines a highly aggressive group of undifferentiated cancer characterized by rapid disease progression that is refractory to conventional platinum/taxane‐based chemotherapy. This underscores the importance of accurate clinical recognition of this aggressive tumor and the need to consider alternative systemic therapy for these tumors.

Small cell neuroendocrine carcinoma of the cervix: diagnostic challenges and emerging molecular insights †

Abstract Small cell neuroendocrine carcinoma of the cervix (SCNECC) is a rare and highly aggressive malignancy with poor prognosis that predominantly affects premenopausal women. Histopathological evaluation is central to diagnosis and clinical management; however, distinguishing SCNECC from other ‘small blue round cell’ malignancies often requires a multimodal approach that integrates morphology, immunohistochemistry, and advanced molecular testing. In the absence of specific and sensitive biomarkers, SCNECC largely remains a diagnosis of exclusion, underscoring the need for comprehensive diagnostic algorithms. A study by Pan, Yan, Yuan et al employed whole transcriptome profiling and identified three molecular subgroups within SCNECC. Importantly, one subgroup displayed an inflamed phenotype, characterized by high expression of MHC‐II complex and IFN‐α/β–related genes, suggesting potential susceptibility to immunotherapy, a finding that mirrors observations in small cell lung cancer. These findings highlight the biological heterogeneity of SCNECC and reinforce the importance of integrating molecular data to refine diagnostic accuracy and guide therapeutic decision‐making. This commentary emphasizes the pressing need for comprehensive diagnostics and further research to advance treatment strategies for this rare and challenging malignancy. © 2025 The Pathological Society of Great Britain and Ireland.

SWI/SNF‐deficient undifferentiated malignancies: where to draw the line†

AbstractAlterations in chromatin remodelling genes are increasingly recognised as drivers of undifferentiated malignancies. In atypical teratoid/rhabdoid tumours (ATRTs) and extracranial rhabdoid tumours (ECRTs), inactivation of SMARCB1 underlies >95% of cases. In the remainder, the culprit is another SWI/SNF family member, SMARCA4. By contrast, in small cell carcinoma of the ovary hypercalcaemic type (SCCOHT), SMARCA4 deficiency is by far the most common driver mechanism, while SMARCB1 alterations are rarely seen. It is unclear why alterations are so heavily weighted towards one or another subunit based on site alone, but both have become essential markers for the diagnosis and management of these undifferentiated lesions. Core SMARCA4‐deficient undifferentiated malignancies share an aggressive clinical course and show an overlapping morphologic phenotype. In their study, Andrianteranagna, Cyrta and colleagues used DNA methylation and gene expression profiling to compare two subsets of SMARCA4‐deficient malignancies diagnosed as SCCOHT and ECRT. Their work gives further insight into the subtle molecular spectrum of SMARCA4‐deficient tumours, and their distinction from ATRT and ECRT with SMARCB1 inactivation. The characterisation of these molecular features is likely to play an important role in the future as we try to establish a clinically meaningful framework for the diagnosis and management of these lesions. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The proteome of clear cell ovarian carcinoma

AbstractClear cell ovarian carcinoma (CCOC) is the second most common subtype of epithelial ovarian carcinoma. Late‐stage CCOC is not responsive to gold‐standard chemotherapy and results in suboptimal outcomes for patients. In‐depth molecular insight is urgently needed to stratify the disease and drive therapeutic development. We conducted global proteomics for 192 cases of CCOC and compared these with other epithelial ovarian carcinoma subtypes. Our results showed distinct proteomic differences in CCOC compared with other epithelial ovarian cancer subtypes including alterations in lipid and purine metabolism pathways. Furthermore, we report potential clinically significant proteomic subgroups within CCOC, suggesting the biologic plausibility of stratified treatment for this cancer. Taken together, our results provide a comprehensive understanding of the CCOC proteomic landscape to facilitate future understanding and research of this disease. © 2022 The Pathological Society of Great Britain and Ireland.

Loss of ARID1B and SMARCB1 expression are specific for the diagnosis of dedifferentiated/undifferentiated carcinoma in tumours of the upper gynaecological tract and cervix

Aims Genomic inactivation of ARID1B in ARID1A‐inactivated tumour and genomic inactivation of SMARCB1 represent two recurrent mechanisms, core SWItch/sucrose non‐fermentable (SWI/SNF) complex inactivation, that are associated with de‐differentiation in endometrial carcinoma. Approximately one‐third of dedifferentiated/undifferentiated endometrial carcinomas (DDEC/UEC) show loss of ARID1B expression with a minor subset showing loss of SMARCB1 expression, but little is known regarding the specificity of ARID1B or SMARCB1 loss in gynaecological tract tumours in general. The aim of this study was to examine the frequency of ARID1B and SMARCB1 loss by immunohistochemistry in a series of gynaecological tract epithelial/mesenchymal neoplasms. Methods and results We evaluated 1849 tumours that included 748 endometrial carcinomas, 101 uterine carcinosarcomas/adenosarcomas, 64 uterine sarcomas, 221 cervical carcinomas and 715 ovarian carcinomas/borderline tumours by tissue microarrays (TMA). We observed ARID1B loss in 35 of 86 (41%) and SMARCB1 loss in three of 86 (3%) DDEC/UEC, but not in any other uterine tumour types examined. ARID1B‐deficient DDEC/UEC also showed concurrent loss of ARID1A expression. All SMARCB1‐deficient tumours showed loss of MLH1 and PMS2, while 29 of 35 ARID1B‐deficient tumours showed loss of MLH1 and PMS2 or loss of MSH6. All ovarian carcinomas/borderline tumours and cervical carcinomas showed intact expression of ARID1B and SMARCB1. Conclusion Our findings indicate that the loss of expression of ARID1B or SMARCB1 by immunohistochemistry is highly specific for undifferentiated carcinoma among tumours of the upper gynaecological tract and cervix, and therefore can be used to identify these highly aggressive malignant tumours.

Molecular characterization of invasive and in situ squamous neoplasia of the vulva and implications for morphologic diagnosis and outcome

Human papillomavirus (HPV)-independent vulvar squamous cell carcinoma (VSCC) is an aggressive clinical entity. Current diagnostic guidelines for premalignant lesions are ambiguous, and their molecular profile and progression events are still unclear. We selected 75 samples, from 40 patients, including 33 VSCC, 8 verrucous carcinomas (VC), 13 differentiated-type vulvar intraepithelial neoplasia (dVIN), 11 suspicious for dVIN (?dVIN), 6 differentiated exophytic vulvar intraepithelial lesions (DE-VIL), 2 vulvar acanthosis with altered differentiation (VAAD), and 2 usual-type vulvar intraepithelial neoplasia (uVIN/HSIL). Invasive and precursor lesions were matched in 29 cases. Clinical information, p16 immunohistochemistry, and mutation analysis were performed on all lesions. All dVIN, ?dVIN, DE-VIL, and VAAD were p16 negative, all uVIN/HSIL were p16 positive. In the HPV-independent group, mutations were identified in 6 genes: TP53 (n = 40), PIK3CA (n = 20), HRAS (n = 12), MET (n = 5), PTEN (n = 4), and BRAF (n = 1). TP53 mutations occurred in 73% (22/30) VSCC, 85% (11/13) dVIN, 70% (7/10) ?dVIN and no VC (0/8), DE-VIL (0/6) nor VAAD (0/2). Basal atypia was the only reliable feature of TP53 mutations. ?dVIN lesions that were non-acanthotic and atypical but obscured by inflammation, all harbored TP53 mutations. In lesions without TP53 mutations, PIK3CA (50% VC, 33% DE-VIL, 100% VAAD, 40% VSCC) and HRAS (63% VC, 33% DE-VIL, 0% VAAD, 20% VSCC) mutations were found. Mutational progression from in situ to invasive was seen (7/26, 27%) and usually involved TP53 (4/26, 15%). Cases with TP53 and PIK3CA co-mutations had the worse clinical outcomes (p < 0.001). We recommend testing for p53 in all HPV-independent lesions suspicious for dVIN, even in the presence of marked inflammation or non-acanthotic skin, particularly when close to a margin. VC, VAAD, and DE-VIL, were almost never mutated for TP53, but instead often harbored PIK3CA and HRAS mutations. In VSCC, combined TP53 and PIK3CA mutations may inform prognosis.

Performance of the pattern‐based interpretation of p53 immunohistochemistry as a surrogate for TP53 mutations in vulvar squamous cell carcinoma

AimsThe most commonly mutated gene in vulvar squamous cell carcinoma (VSCC) is TP53 and its prognostic value, particularly in HPV‐independent VSCC, is uncertain. In other tumours, p53 immunohistochemistry (IHC) is an excellent surrogate marker for TP53 mutations. In order to study this in VSCC, we assigned six p53 IHC patterns into two final classes: ‘wild‐type’ or ‘mutant’. We determined the performance and interobserver variability of this pattern‐based p53 IHC approach.Methods and resultsTwo experienced gynaecological pathologists scored the predefined p53 IHC patterns of 59 VSCC, independently and blinded for molecular data. Agreement was calculated by Cohen's kappa. All disagreements regarding p53 IHC patterns were resolved by a consensus meeting. After DNA isolation, the presence of pathogenic TP53 variants was determined by next‐generation sequencing (NGS). Sensitivity, specificity and accuracy of p53 IHC as a surrogate marker for TP53 mutation status were calculated. Initial p53 IHC pattern interpretation showed substantial agreement between both observers (k = 0.71, P &lt; 0.001). After consensus, 18 cases (30.5%) were assigned a final p53 IHC class as TP53 wild‐type and 41 cases (69.5%) as mutant. The accuracy between the p53 IHC class and TP53 mutation status, after the consensus meeting, was 96.6%. Moreover, the sensitivity and specificity were high 95.3% [95% confidence interval (CI) = 82.9–99.1% and 100% (95% CI = 75.9–100%)].ConclusionsPattern‐based p53 IHC classification is highly reproducible among experienced gynaecological pathologists and accurately reflects TP53 mutations in VSCC. This approach to p53 IHC interpretation offers guidance and provides necessary clarity for resolving the proposed prognostic relevance of final p53 IHC class within HPV‐independent VSCC.

Major p53 immunohistochemical patterns in in situ and invasive squamous cell carcinomas of the vulva and correlation with TP53 mutation status

The recent literature has shown that vulvar squamous cell carcinoma (VSCC) can be stratified into two prognostically relevant groups based on human papillomavirus (HPV) status. The prognostic value of p53 for further sub-stratification, particularly in the HPV-independent group, has not been agreed upon. This disagreement is likely due to tremendous variations in p53 immunohistochemical (IHC) interpretation. To address this problem, we sought to compare p53 IHC patterns with TP53 mutation status. We studied 61 VSCC (48 conventional VSCC, 2 VSCC with sarcomatoid features, and 11 verrucous carcinomas) and 42 in situ lesions (30 differentiated vulvar intraepithelial neoplasia [dVIN], 9 differentiated exophytic vulvar intraepithelial lesions [deVIL], and 3 high-grade squamous intraepithelial lesions or usual vulvar intraepithelial neoplasia [HSIL/uVIN]). IHC for p16 and p53, and sequencing of TP53 exons 4-9 were performed. HPV in situ hybridization (ISH) was performed in selected cases. We identified six major p53 IHC patterns, two wild-type patterns: (1) scattered, (2) mid-epithelial expression (with basal sparing), and four mutant patterns: (3) basal overexpression, (4) parabasal/diffuse overexpression, (5) absent, and (6) cytoplasmic expression. These IHC patterns were consistent with TP53 mutation status in 58/61 (95%) VSCC and 39/42 (93%) in situ lesions. Cases that exhibited strong scattered staining and those with a weak basal overexpression pattern could be easily confused. The mid-epithelial pattern was exclusively observed in p16-positive lesions; the basal and parabasal layers that had absent p53 staining, appeared to correlate with the cells that were positive for HPV-ISH. This study describes a pattern-based p53 IHC interpretation framework, which can be utilized as a surrogate marker for TP53 mutational status in both VSCC and vulvar in situ lesions.

Presence and extent of lymphovascular invasion in surgical stage I squamous cell carcinoma of the cervix: a comprehensive, international, multicentre, retrospective clinicopathological study

The aim of this study was to determine whether the presence and extent of lymphovascular invasion (LVI) is prognostic in surgical stage I cervical squamous cell carcinoma (SCC). All available tumour slides and/or paraffin blocks from 426 patients with stage I cervical SCC treated surgically with curative intent were collected from 18 institutions and retrospectively analysed. Presence and extent of LVI (focal <5 spaces, extensive ≥5 spaces) were assessed on scanning magnification in large haematoxylin and eosin slide sets in 366 cases. Progression-free survival (PFS) was calculated as the time from surgery to first progression or death or last follow-up, whichever occurred first. Overall survival (OS) was defined as the time from surgery to death or last follow-up. Clinicopathological and statistical analyses were performed on 97 patients with the International Federation of Gynecology and Obstetrics (FIGO) 2018 stage IA and 329 patients with stage IB SCC of the cervix. LVI, both focal and extensive, was more frequent in stage IB than in stage IA (p<0.001). Patients with stage IB carcinomas with extensive LVI had worse PFS [hazard ratio (HR) 2.86; 95% confidence interval (CI) 1.49, 5.49; p=0.005] and OS (HR 2.88; 95% CI 1.38, 6.02; p=0.012) than those with focal or no LVI. In stage IA, in contrast, the presence and extent of LVI did not associate with PFS (p=0.926) or OS. Extensive LVI was not statistically correlated with PFS and OS in substages IA1, IA2 or IB2. PFS (HR 3.7; 95% CI 1.61, 8.46; p<0.001) and OS (HR 4.18; 95% CI 1.58, 11.04; p=0.002) in stage IB1, and PFS (HR 7.78; 95% CI 0.87, 69.82; p=0.039) in stage IB3 were diminished in the presence of extensive LVI. In conclusion, in patients with FIGO stage I cervical SCC, the presence and extent of LVI has prognostic significance in stage IB carcinoma, and quantifying LVI is recommended.