A Curious Case of Clear Cell Morphology in a Patient with Lung Cancer: Diagnostic Challenges.

An 82-year-old woman with COPD presented to the emergency department with cough, increasing sputum production, wheezing, and worsening shortness of breath for two weeks. On imaging studies, the patient was found to have a right upper lobe spiculated nodule and an endobronchial lesion with near total occlusion of the right lower lobe bronchus with sub-segmental atelectasis. Bronchoscopy with EBUS-TBNA of subcarinal and right hilar lymph nodes revealed lung cancer with clear cell phenotype. Given the predominance of clear cell morphology, the diagnosis of metastatic renal or ovarian cancer was entertained. However, there was no evidence of renal or ovarian lesions on the PET-CT scan, ruling out the possibility. Salivary gland type lung cancer (STLC), which is responsible for less than 1% of all lung cancer cases in adults, was also considered. The two distinct STLCs that may have similar morphologic appearances are hyalinizing clear cell carcinoma (HCCC) and mucoepidermoid carcinoma (MEC). The other type of tumour in the lung that demonstrates a clear cell phenotype is perivascular epithelioid cell neoplasms or PEComa, which are mesenchymal in origin. Immunohistochemical staining was strongly positive for p63, CK5/6, CK7, CK-LMW, and negative for TTF-1, Napsin A, p16, and CK20. Additional staining, including HMB-45, S-100, and mucicarmine, were also negative. Next-generation sequencing for the salivary gland fusion panel, including EWSR1-ATF1 fusion and EWSR1 gene rearrangement for HCCC and MAML2 gene rearrangements for MEC, was negative. She was diagnosed with non-small cell lung cancer favouring squamous cell carcinoma with clear cell phenotype, a rare entity.

Global Incidence of Ovarian Cancer According to Histologic Subtype: A Population-Based Cancer Registry Study.

PURPOSE: Ovarian cancer can be categorized into distinct histologic subtypes with varying identifiable risk factors, molecular composition, clinical features, and treatment. The global incidence of ovarian cancer subtypes remains limited, especially in low- and middle-income countries (LMICs) without high-quality cancer registry systems. MATERIALS AND METHODS: We used data from population-based cancer registries of the Cancer Incidence in Five Continents project to calculate the proportions of serous, mucinous, endometrioid, clear cell, and other histologic subtypes of ovarian cancer. Proportions were applied to the estimated numbers of patients with ovarian cancer from Global Cancer Observatory 2020. Age-standardized incidence rates were calculated. RESULTS: Globally, an estimated 133,818 new patients of serous cancer, 35,712 new patients of mucinous cancer, 29,319 new patients of endometrioid cancer, and 17,894 new patients of clear cell cancer were identified in 2020. The distribution of ovarian cancer histologic subtypes exhibited regional variation. Eastern Europe had the highest rate of serous and mucinous carcinomas, whereas Northern Africa and Eastern Asia had the highest burden of endometrioid and clear cell carcinomas, respectively. CONCLUSION: This study provides a global incidence landscape of histologic subtypes of ovarian cancer, particularly in LMICs lacking comprehensive registry systems. Our analysis offers valuable insights into disease burden and guidance for tailored strategies for prevention of ovarian cancer.

Novel Ultrastructural Insights into the Clear-Cell Carcinoma of the Pancreas: A Case Report.

Pancreatic cancer, most frequently as ductal adenocarcinoma (PDAC), is the third leading cause of cancer death. Clear-cell primary adenocarcinoma of the pancreas (CCCP) is a rare, aggressive, still poorly characterized subtype of PDAC. We report here a case of a 65-year-old male presenting with pancreatic neoplasia. A histochemical examination of the tumor showed large cells with clear and abundant intracytoplasmic vacuoles. The clear-cell foamy appearance was not related to the hyperproduction of mucins. Ultrastructural characterization with transmission electron microscopy revealed the massive presence of mitochondria in the clear-cell cytoplasm. The mitochondria showed disordered cristae and various degrees of loss of structural integrity. Immunohistochemistry staining for NADH dehydrogenase [ubiquinone] 1 alpha subcomplex, 4-like 2 (NDUFA4L2) proved specifically negative for the clear-cell tumor. Our ultrastructural and molecular data indicate that the clear-cell nature in CCCP is linked to the accumulation of disrupted mitochondria. We propose that this may impact on the origin and progression of this PDAC subtype.

Targeting PDGF signaling of cancer-associated fibroblasts blocks feedback activation of HIF-1α and tumor progression of clear cell ovarian cancer.

Ovarian clear cell carcinoma (OCCC) is a gynecological cancer with a dismal prognosis; however, the mechanism underlying OCCC chemoresistance is not well understood. To explore the intracellular networks associated with the chemoresistance, we analyze surgical specimens by performing integrative analyses that combine single-cell analyses and spatial transcriptomics. We find that a chemoresistant OCCC subpopulation with elevated HIF activity localizes mainly in areas populated by cancer-associated fibroblasts (CAFs) with a myofibroblastic phenotype, which is corroborated by quantitative immunostaining. CAF-enhanced chemoresistance and HIF-1α induction are recapitulated in co-culture assays, which show that cancer-derived platelet-derived growth factor (PDGF) contributes to the chemoresistance and HIF-1α induction via PDGF receptor signaling in CAFs. Ripretinib is identified as an effective receptor tyrosine kinase inhibitor against CAF survival. In the co-culture system and xenograft tumors, ripretinib prevents CAF survival and suppresses OCCC proliferation in the presence of carboplatin, indicating that combination of conventional chemotherapy and CAF-targeted agents is effective against OCCC.

Case of metastatic clear cell odontogenic carcinoma with response to chemoimmunotherapy.

Our patient initially presented with 6 months of left jaw pain and gingival bleeding, leading to the discovery of a radiolucent left maxillary mass on dental evaluation. A biopsy confirmed clear cell odontogenic carcinoma, and the patient was treated with definitive surgery and radiation for localised disease. Unfortunately, the patient was found to have pulmonary metastases 3 months after initial management and was subsequently treated with a combination of cytotoxic chemotherapy and immunotherapy with a partial response. To our knowledge, this is the first case demonstrating the successful use of chemoimmunotherapy in metastatic clear cell odontogenic carcinoma.

PURE vs. mixed clear cell ovarian carcinomas: Is there any impact on survival?

OBJECTIVE: Our primary aim in this study is to define the clinical characteristics of patients with clear-cell ovarian carcinoma and evaluate the prognostic factors affecting survival. STUDY DESIGN: Records of 85 patients, operated between 2000 and 2018, for an adnexal mass and whose final pathology reported clear cell ovarian carcinoma were reviewed. The study considered demographic data, clinical characteristics of the patients, as well as pure and mixed-type clear cell histology. The patients' follow-up time, disease-free and overall survival recorded. The primary outcomes were disease-free survival (DFS) and overall survival (OS). RESULTS: The median age of the patients at diagnosis was 52. In 64.7 % of the cases, clear cell histology was pure, while the others (35.3 %) were mixed. Patients with ovarian endometriosis constituted 27.1 % of the whole population. The median OS for the entire population was 92 months (95 %CI:72-124). On univariate and multivariate analyses, advanced age was found to have a significant independent impact on OS and DFS (p < 0.05) and, was associated with a worse prognosis. Also, the multivariate analyses showed that the presence of endometriosis has a significant independent impact on OS (p < 0.05). When examining the relationship between the histological origin (mixed vs. pure) and 5-year survival, the mixed type showed longer OS and DFS rates (76.8 % vs. 69.8 %, 61.5 % vs. 53.8 %), the difference was not statistically significant (p > 0.05). CONCLUSION: This retrospective study showed that although mixed type histological origin was associated with higher OS and DFS rates compared to pure type in patients with CCOC, the difference was not statistically significant. Advanced age and the presence of endometriosis was found to have a significant independent effect on OS and DFS and was associated with a worse prognosis. Overall, this study provides useful insights into the clinical characteristics of patients with CCOC and identifies important prognostic factors affecting survival.

Differentiation of ovarian serous carcinoma from ovarian clear cell carcinoma using a 10-gene signature selected by comprehensive gene expression analysis.

AIM: Ovarian serous carcinoma (OSC) and ovarian clear cell carcinoma (OCCC) are two major histological types of epithelial ovarian carcinoma (EOC), each with different biological features and clinical behaviors. Although immunostaining is commonly used for differential diagnosis between OSC and OCCC, correct identification of EOC with mixed-type histology is sometimes a diagnostic challenge. The aim of the present study was to explore candidate genes as potential diagnostic biomarkers that distinguish OSC from OCCC. METHODS: A total of 57 surgical specimens were obtained from EOC patients who had previously undergone primary debulking surgery. Total RNAs were extracted from fresh-frozen tissues of EOC patients, and were used for comprehensive gene expression analysis using DNA microarray technology. RESULTS: Ten candidate genes, FXYD2, TMEM101, GABARAPL1, ARG2, GLRX, RBPMS, GDF15, PPP1R3B, TOB1, and GSTM3 were up-regulated in OCCC compared to OSC. All EOC patients were divided into two groups according to hierarchical clustering using a 10-gene signature. CONCLUSION: Our data suggest that the 10 candidate genes would be an excellent marker for distinguishing OSC from OCCC. Furthermore, the molecular signatures of the 10 genes may enlighten us on the differences in carcinogenesis, and provide a theoretical basis for OCCC's resistance to chemotherapy in the future.

Cervical clear cell carcinoma: Case report and literature review.

RATIONALE: Clear cell carcinoma (CCC) is a highly invasive malignant tumor. CCCs of the female reproductive system occur mostly in the endometrium and ovaries and rarely in the cervix. So, it is difficult to diagnose cervical clear cell carcinoma (CCAC) on imaging. This report helps to further deepen our understanding of CCAC. PATIENT CONCERNS: A 39-year-old female patient presented with vaginal discharge with no obvious cause, elevated levels of carcinoembryonic antigen (CEA), CA125, CA153, and squamous cell carcinoma antigen (SCC), and underwent ultrasonography (US) CT and MRI examination in our hospital, which showed a mass in the cervix of the uterus, considered of cervical squamous carcinoma. DIAGNOSES: The cervix biopsy guided by vaginoscope biopsy and immunohistochemistry confirmed CCAC, combined Magnetic Resonance Imaging examination, CCAC with pelvic lymph node metastasis was considered. INTERVENTIONS AND OUTCOMES: The patient refused further treatment and was discharged from hospital. LESSONS: CCAC exhibited no specific symptoms, and is slightly different from cervical squamous carcinoma in image features, mainly relying on immunohistochemistry for diagnosis. The reported case raised awareness of CCAC.

Histologic Subtypes in Endometriosis-Associated Ovarian Cancer and Ovarian Cancer Arising in Endometriosis: A Systematic Review and Meta-Analysis.

The definition of the association between ovarian cancer and endometriosis was first reported by Sampson in 1925. He identified the following criteria: (a) clear evidence of endometriosis in proximity to the tumour, (b) exclusion of a metastatic tumour to the ovary, (c) presence of tissue resembling endometrial stroma surrounding epithelial glands. The naming of these cancers is "endometriosis-associated ovarian cancer" (EAOC). Scott proposed an additional stringent criterion: evidence of histological transition from endometriosis to cancer is to define "ovarian cancer arising in endometriosis" (OCAE). The aim of this systematic review is to analyse the distribution of different ovarian cancer histotypes in EAOC and OCAE to understand their similarities and differences. A total of 31 studies were included. Four studies added data for both EAOC and OCAE. Twenty-three studies were selected for EAOC, with a total of 800 patients, and 12 studies were selected for OCAE, with a total of 375 patients. The results show no significant differences in the distribution of histotypes in the two populations analysed. Clear cell carcinoma (CCC) and endometrioid carcinoma (EC) were the most common subtypes and were less frequent in EAOC compared to OCAE; the odd ratios were 0.58 (0.26-1.29) and 0.65 (0.33-1.26) respectively, although the difference was not statistically significant. The other histotypes were present in small proportions. This analysis shows that the histological profiles of EAOC and OCAE are similar, suggesting a similar aetiopathological mechanism, which requires further research to investigate whether EAOC and OCAE may be in the same way but at different points of the process to malignancy or have different pathways of progression to malignancy.

Pulmonary salivary gland tumor-hyalinizing clear cell carcinoma: a literature review.

Primary pulmonary hyalinizing clear cell carcinoma (HCCC) is a very rare lung tumor that accounts for less than 0.09% of all primary lung tumors and has no specific epidemiology. The correct diagnosis requires imaging, laboratory, pathological, immunohistochemical, and molecular examination. The most typical feature of pulmonary HCCC is the clear cell component with clear stroma. In addition, the fusion gene EWSR1::ATF1 due to t(12;22)(q13;q12) is essential for the pathological diagnosis of pulmonary HCCC. The main treatment for pulmonary HCCC is surgery. This review focus on the pathological features, immunohistochemical examination, mutation analysis and treatment of pulmonary HCCC.

The impact of lymphadenectomy on ovarian clear cell carcinoma: a systematic review and meta-analysis.

BACKGROUND: Ovarian clear cell carcinoma (OCCC) shares treatment strategies with epithelial ovarian cancer (EOC). Due to OCCC's rarity, there's a lack of prospective studies on its surgery, resulting in heterogeneous and limited existing data. This study aims to clarify the prognostic significance of lymphadenectomy in OCCC patients. METHODS: We systematically searched Web of Science, Scopus, PubMed, and Google Scholar until July 2023 for studies investigating lymphadenectomy's effects on OCCC patients. We calculated pooled hazard ratios (HR) with 95% confidence intervals (CI). This study is registered in PROSPERO (CRD42021270460). RESULTS: Among 444 screened articles, seven studies (2883 women) met inclusion criteria. Our analysis revealed that lymphadenectomy significantly improved disease-specific survival (DSS) (HR = 0.76, 95%CI = 0.60-0.95, P = 0.02) and disease-free survival (DFS) (HR = 0.58, 95%CI = 0.34-0.99, P = 0.05). However, it did not significantly affect overall survival (OS) (HR = 0.80, 95%CI = 0.60-1.06, P = 0.12) or progression-free survival (PFS) (HR = 0.95, 95%CI = 0.64-1.42, P = 0.79). Notably, some earlier studies reported no survival benefit, warranting cautious interpretation. CONCLUSION: Lymphadenectomy does not significantly enhance OS and PFS for OCCC but does improve DFS and DSS. Tailoring treatment to individual patient profiles is imperative for optimal outcomes. Precise preoperative or intraoperative lymph node metastasis detection is essential for identifying candidates benefiting from lymphadenectomy. Collaborative international efforts and an OCCC database are pivotal for refining future treatment strategies.

Hyalinizing Clear Cell Carcinoma in the Sphenoid Sinus.

ABSTRACT: A 39-year-old man presented with a 1-month history of headaches. Imaging revealed a mass with extensive destruction. T2-weighted imaging displayed mixture of low and sponge-like high intensities and also dark area, with FDG PET/CT showing uneven but intense accumulation. Biopsy confirmed EWSR1 rearrangement, and hyalinizing clear cell carcinoma (HCCC) was diagnosed. HCCC, recently renamed from clear cell carcinoma in the fifth edition of the World Health Organization Classification of Head and Neck Tumors, is a rare tumor. This case describes the features of T2-weighted imaging and FDG PET patterns in HCCC, possibly contributing to their consideration in the differential diagnosis.

Practice patterns, time trends and quality of care of uterine cancer in Belgium: An analysis of the EFFECT database.

OBJECTIVES: To investigate the practice patterns and quality of care for uterine cancer on a national level in Belgium, including trends in practice over the period 2012-2016. METHODS: Quality indicators were measured using the EFFectiveness of Endometrial Cancer Treatment (EFFECT) database. Multivariable logistic mixed regression was used to test for associations between the quality indicators and year of diagnosis, adjusted for potential confounders and intra-cluster correlations. RESULTS: The EFFECT database includes 4178 patients diagnosed with uterine cancer in the period 2012-2016. Minimally invasive surgery (laparoscopic or robotic-assisted) was applied in 61.6% of patients who had surgery for clinical stage I endometrial carcinoma (EC), increasing from 52.9% in 2012 to 66.4% in 2016. At least pelvic lymph node staging was performed in 69.0% of patients with clinical stage I, high-grade EC; and in 63.9% of patients with clinical stage I-II serous carcinoma, clear cell carcinoma or carcinosarcoma. The latter increased from 48.8% in 2012 to 77.2% in 2016. Adjuvant radiotherapy (external beam and/or brachytherapy) was offered to 33.5% of patients who had surgery without lymph node staging for pathological stage I EC at high-intermediate or high risk of recurrence. Adjuvant chemotherapy was administered to 64.4% of patients with pathological stage III-IVA EC. CONCLUSIONS: Study results indicate an overall good quality of care for patients with uterine cancer in Belgium. Treatment areas with potential room for improvement include the use of minimally invasive surgery, comprehensive surgical staging and adjuvant therapy, which confirms the remaining controversies in uterine cancer treatment and the need for further research.

Clear Cell Adenocarcinoma of Urethra: Clinical and Pathologic Implications and Characterization of Molecular Aberrations.

PURPOSE: This study aimed to evaluate the molecular features of clear cell adenocarcinoma (CCA) of the urinary tract and investigate its pathogenic pathways and possible actionable targets. MATERIALS AND METHODS: We retrospectively collected the data of patients with CCA between January 1999 and December 2016; the data were independently reviewed by two pathologists. We selected five cases of urinary CCA, based on the clinicopathological features. We analyzed these five cases by whole exome sequencing (WES) and subsequent bioinformatics analyses to determine the mutational spectrum and possible pathogenic pathways. RESULTS: All patients were female with a median age of 62 years. All tumors were located in the urethra and showed aggressive behavior with disease progression. WES revealed several genetic alterations, including driver gene mutations (AMER1, ARID1A, CHD4, KMT2D, KRAS, PBRM1, and PIK3R1) and mutations in other important genes with tumor-suppressive and oncogenic roles (CSMD3, KEAP1, SMARCA4, and CACNA1D). We suggest putative pathogenic pathways (chromatin remodeling pathway, mitogen-activated protein kinase signaling pathway, phosphoinositide 3-kinase/AKT/mammalian target of rapamycin pathway, and Wnt/ß-catenin pathway) as candidates for targeted therapies. CONCLUSION: Our findings shed light on the molecular background of this extremely rare tumor with poor prognosis and can help improve treatment options.

Trends in the incidence and survival outcomes of endometrial cancer in Korea: a nationwide population-based cohort study.

OBJECTIVE: To evaluate trends in the incidence and survival outcomes of endometrial cancer (EC) based on the year of diagnosis, stage, age, and histologic types. METHODS: Women with primary EC diagnosed between 1999 and 2018, and who were followed up with until 2019, were identified from the Korea Central Cancer Registry using the International Classification of Diseases, 10th revision. The age-standardized rates (ASRs) of incidence, annual percent changes (APCs), and survival were estimated according to age, stage, histology, and year of diagnosis. RESULTS: The ASR for EC increased from 2.38 per 100,000 in 1999 to 7.29 per 100,000 in 2018 across all histologic types (APCs of 9.82, 15.97, and 7.73 for endometrioid, serous, and clear cell, respectively, p<0.001). There were significant differences in the 5-year survival rates based on histology (90.9%, 55.0%, and 68.5% for endometrioid, serous, and clear cell, respectively, p<0.001), stage (93.4%, 77.0%, and 31.0% for localized, regional, and distant, respectively, p<0.001), and age (93.0% for <50 years and 80.6% for ≥50 years, p<0.001). The 5-year survival was significantly better in the group diagnosed between 2000 and 2018 (85.9%) than that in the 1999-2008 group (83.3%) (p<0.001). This trend was only observed for endometrioid cancer (p<0.001). CONCLUSION: The incidence of EC increased across the all 3 subtypes. Survival of patients with endometrioid histology improved over the past two decades, but remained static for serous or clear cell histology. Healthcare strategies to prevent EC incidence in at-risk populations and apply effective treatments for high-risk histology are needed.

Immunohistochemical Analysis of the Tissue Factor Pathway Inhibitor-2 in Endometrial Clear Cell Carcinoma: A Single-center Retrospective Study.

The tissue factor pathway inhibitor-2 (TFPI2) was recently identified as a diagnostic serum marker for ovarian clear cell carcinoma. Moreover, the immunohistochemical expression of TFPI2 in ovarian clear cell carcinoma was recently reported. This single-center retrospective study aimed to evaluate whether TFPI2 can be a specific biomarker for immunohistological diagnosis of endometrial clear cell carcinoma (ECCC). Immunohistochemical staining of TFPI2 in 55 endometrial carcinomas was evaluated at Nara Medical University Hospital. Thirteen ECCC samples were included as cases and 42 samples were included as a control (endometrioid carcinoma grade 1, 11 cases; grade 2, 11 cases; grade 3, 10 cases; serous carcinoma, 10 cases). The mean ± SD TFPI2 histoscore for diagnosing ECCC was 115.4 ± 87.9, which was significantly higher than that of non-ECCC (21.3 ± 45.9, P = 0.002). The best TFPI2 histoscore value obtained from the analyses of receiver operating characteristic curves for immunohistochemical diagnosis of ECCC was 15. With TFPI2 histoscores ≥15.0 as positive and <15.0 as negative, all 13 ECCC cases (100%) were positive for TFPI2, whereas 11 (26.2%) non-ECCC cases were positive for TFPI2. The sensitivity and specificity of TFPI2 for diagnosing ECCC were 100% and 73.8%, respectively. TFPI2 is expressed in ECCC and is useful for histopathological diagnosis.

Correlation of clinicopathological and prognostic characteristics between endometriosis-associated and primary ovarian cancer.

BACKGROUND: The main aim of this study was to establish the clinicopathological and prognostic correlations between endometriosis-associated and non-endometriosis-associated primary ovarian cancer, with a view to providing a reference guide for revision of diagnostic criteria for malignant transformation of endometriosis. METHODS: Clinicopathological and follow-up data of 174 patients with clear cell and endometrial ovarian cancer were retrospectively extracted. Cases were divided into endometriosis-associated and non-endometriosis-associated primary ovarian cancer for comparative analysis of clinicopathological characteristics and prognosis. RESULTS: Average age and post-menopausal rate in the endometriosis-associated ovarian cancer group were lower relative to the primary ovarian cancer group (P < 0.05). Body mass index, age at menopause, operation history, dysmenorrhea, complications, tumor size, tumor side, ascites, CA125, HE4, CA19.9, stage, differentiation, expression of ER, PR, P53, P16, Ki67, MMR, HNF-1ß and Napsin A were not significantly different between the groups (P > 0.05). Furthermore, rates of resistance to platinum chemotherapy, relapse, progression-free survival and overall survival were comparable between the two groups (P > 0.05). CONCLUSION: Endometriosis-associated and primary ovarian cancers of the same pathological type are speculated to be homologous in terms of origin from malignant transformation of endometriosis. It may therefore be necessary to revise the diagnostic criteria for ovarian endometriosis malignancy.

Prognosis and adjuvant chemotherapy for patients with malignant peritoneal cytology in early-stage non-endometrioid endometrial cancer.

OBJECTIVE: To investigate the influence of malignant peritoneal cytology (MPC) on the prognosis of early-stage patients with endometrial clear cell carcinoma(CCC) and serous carcinoma(SC), and the value of chemotherapy in their treatment. METHODS: A retrospective observational cohort study was conducted by querying the National Cancer Institute's Surveillance, Epidemiology, and End Results Program from 2010 to 2019. Women with early-stage CCC and SC with available peritoneal cytology results were enrolled. Propensity score matching(PSM) and propensity score inverse probability of treatment weighting (IPTW) was used to balance the measured covariates in each sub-cohort. RESULTS: A total of 3,616 eligible patients were included, and 368 patients had MPC (10.2%). Women with MPC were more likely to receive postoperative chemotherapy (OR 2.033; 95%CI 1.589-2.602). In PSM model, MPC had worse overall survival(OS) and cancer-specific survival (CSS) (All,p < 0.001). The 5-year OS rates were 56.5% for women with MPC and 74.4% for those with negative peritoneal cytology, and the 5-year CSS rates were 60.8% versus 80.0%(All, p < 0.0001). In the subgroup analyses, MPC was associated with decreased OS and CSS in serous, clear cell histology group, and stage IA cases(All,p < 0.001), but not for stage IB or stage II disease. In multivariate analysis, chemotherapy improved the prognosis of patients with MPC(OS:p = 0.005; CSS:p = 0.010). Additionally, in stage IA subgroup, chemotherapy improved survival outcomes in patients with MPC(OS:P = 0.025; CSS:P = 0.038), in NPC patients, however, chemotherapy was a good prognostic factor for OS (P = 0.001) but not for CSS(P = 0.300). CONCLUSION: MPC was a prognostic factor for decreased survival in early-stage endometrial CCC and SC, and those with MPC could further benefit from chemotherapy.