Short Term Exposure of Sheep Tracheal Epithelium to Cigarette Smoke Extract Reduces ENaC Current: A Pilot Study.

BACKGROUND/AIM: Cigarette smoke has been shown to induce a phenotype in humans known as "acquired cystic fibrosis". This occurs because the cystic fibrosis transmembrane conductance regulator (CFTR) functions are impaired systemically due to the deleterious effects of smoke components. Elucidation of cigarette smoke effects on the tracheal epithelium is important. The aim of this study was to develop an ex vivo sheep tracheal model to investigate tracheal ion function. In this model, the epithelial sodium channel (ENaC) is inhibited after exposure to cigarette smoke extract (CSE) as a proof of principle. MATERIALS AND METHODS: Tracheas were isolated from healthy sheep and the tracheal epithelium was surgically excised. Tissues were mounted in Ussing chambers and the short circuit current (Isc) was measured after incubation with 5% CSE in PBS or PBS alone for 30 min. The function of ENaC was investigated by the addition of amiloride (10-5M) apically. Western blot analysis was performed to assess differences in ENaC quantity after CSE exposure. Some specimens were stained with H&E for detection of histological alterations. RESULTS: The amiloride effect on normal epithelium led to a significant decrease in Isc [ΔI=33±5.92 µA/cm2; p<0.001 versus control experiments (ΔI=1.44±0.71 µA/cm2)]. After incubation with CSE, ENaC Isc was significantly reduced (ΔI=14.80±1.96 µA/cm2; p<0.001). No differences in αENaC expression were observed between CSE-exposed and normal tracheal epithelium. Histological images post CSE incubation revealed decreases in the height of the epithelium, with basal cell hyperplasia and loss of ciliated cells. CONCLUSION: Reduced ENaC inhibition by amiloride after CSE incubation could be due to alterations in the tracheal epithelium.

Tau is required for glial lipid droplet formation and resistance to neuronal oxidative stress.

The accumulation of reactive oxygen species (ROS) is a common feature of tauopathies, defined by Tau accumulations in neurons and glia. High ROS in neurons causes lipid production and the export of toxic peroxidated lipids (LPOs). Glia uptake these LPOs and incorporate them into lipid droplets (LDs) for storage and catabolism. We found that overexpressing Tau in glia disrupts LDs in flies and rat neuron-astrocyte co-cultures, sensitizing the glia to toxic, neuronal LPOs. Using a new fly tau loss-of-function allele and RNA-mediated interference, we found that endogenous Tau is required for glial LD formation and protection against neuronal LPOs. Similarly, endogenous Tau is required in rat astrocytes and human oligodendrocyte-like cells for LD formation and the breakdown of LPOs. Behaviorally, flies lacking glial Tau have decreased lifespans and motor defects that are rescuable by administering the antioxidant N-acetylcysteine amide. Overall, this work provides insights into the important role that Tau has in glia to mitigate ROS in the brain.

Laryngeal rare benign non-epithelial tumors and sarcomas emphasizing on chondrosarcomas: A literature review and a case presentation.

Laryngeal rare tumors include benign and malignant tumors of epithelial, non-epithelial, or mesenchymal origin. Chondrosarcomas are the most common mesenchymal malignant tumors of the larynx. We performed a literature review (Pubmed/Medline; PRISMA 2020) to detect the frequency of published studies from 2021 to April 2024 regarding benign and malignant epithelial, non-epithelial, or mesenchymal rare tumors of the larynx, emphasizing laryngeal chondrosarcoma (LC) cases. Articles including cases discussed before 2021 were excluded and articles without available English translations. We included 154 articles investigating rare tumors of the larynx, the majority of them discussed non-epithelial or mesenchymal entities (75 %). Specifically, a high proportion of studies examined benign non-epithelial or mesenchymal tumors (79.5 %) or mesenchymal rare malignancies (72 %) of the larynx concerning epithelial tumors in the last three years. Sarcomas were discussed in 74 % of mesenchymal laryngeal malignancies and more than 50 % of rare laryngeal tumor studies, and LC was discussed in ∼50 % of laryngeal sarcoma studies. LC studies reported 174 cases, 21 % of them of high-grade LC (II), including a new case of LC presented here in the supraglottic (grade II), which showed intense staining for the S100 marker. Our study highlights the awareness of rare laryngeal tumors emphasizing non-epithelial benign tumors and laryngeal sarcomas, including chondrosarcomas, as pathologic entities of the larynx. Although the majority of LC included low-grade neoplasms, a markedness proportion of LC cases was evaluated as high-grade. Future research approaches, including a range of low and high-grade tumors, would reveal prognostic markers or therapeutic targets for LC and other rare laryngeal malignancies of non-epithelial or mesenchymal origin.

Hypoxia-inducible factor 1alpha and vascular endothelial growth factor in Glioblastoma Multiforme: a systematic review going beyond pathologic implications.

Glioblastoma multiforme (GBM) is an aggressive primary brain tumor characterized by extensive heterogeneity and vascular proliferation. Hypoxic conditions in the tissue microenvironment are considered a pivotal player leading tumor progression. Specifically, hypoxia is known to activate inducible factors, such as hypoxia-inducible factor 1alpha (HIF-1α), which in turn can stimulate tumor neo-angiogenesis through activation of various downward mediators, such as the vascular endothelial growth factor (VEGF). Here, we aimed to explore the role of HIF-1α/VEGF immunophenotypes alone and in combination with other prognostic markers or clinical and image analysis data, as potential biomarkers of GBM prognosis and treatment efficacy. We performed a systematic review (Medline/Embase, and Pubmed database search was completed by 16th of April 2024 by two independent teams; PRISMA 2020). We evaluated methods of immunoassays, cell viability, or animal or patient survival methods of the retrieved studies to assess unbiased data. We used inclusion criteria, such as the evaluation of GBM prognosis based on HIF-1α/VEGF expression, other biomarkers or clinical and imaging manifestations in GBM related to HIF-1α/VEGF expression, application of immunoassays for protein expression, and evaluation of the effectiveness of GBM therapeutic strategies based on HIF-1α/VEGF expression. We used exclusion criteria, such as data not reporting both HIF-1α and VEGF or prognosis. We included 50 studies investigating in total 1319 GBM human specimens, 18 different cell lines or GBM-derived stem cells, and 6 different animal models, to identify the association of HIF-1α/VEGF immunophenotypes, and with other prognostic factors, clinical and macroscopic data in GBM prognosis and therapeutic approaches. We found that increased HIF-1α/VEGF expression in GBM correlates with oncogenic factors, such as miR-210-3p, Oct4, AKT, COX-2, PDGF-C, PLDO3, M2 polarization, or ALK, leading to unfavorable survival. Reduced HIF-1α/VEGF expression correlates with FIH-1, ADNP, or STAT1 upregulation, as well as with clinical manifestations, like epileptogenicity, and a favorable prognosis of GBM. Based on our data, HIF-1α or VEGF immunophenotypes may be a useful tool to clarify MRI-PET imaging data distinguishing between GBM tumor progression and pseudoprogression. Finally, HIF-1α/VEGF immunophenotypes can reflect GBM treatment efficacy, including combined first-line treatment with histone deacetylase inhibitors, thimerosal, or an active metabolite of irinotecan, as well as STAT3 inhibitors alone, and resulting in a favorable tumor prognosis and patient survival. These data were supported by a combination of variable methods used to evaluate HIF-1α/VEGF immunophenotypes. Data limitations may include the use of less sensitive detection methods in some cases. Overall, our data support HIF-1α/VEGF's role as biomarkers of GBM prognosis and treatment efficacy.

State of the Art in Low-Grade Glioma Management: Insights From Isocitrate Dehydrogenase and Beyond.

Low-grade gliomas present a formidable challenge in neuro-oncology because of the challenges imposed by the blood-brain barrier, predilection for the young adult population, and propensity for recurrence. In the past two decades, the systematic examination of genomic alterations in adults and children with primary brain tumors has uncovered profound new insights into the pathogenesis of these tumors, resulting in more accurate tumor classification and prognostication. It also identified several common recurrent genomic alterations that now define specific brain tumor subtypes and have provided a new opportunity for molecularly targeted therapeutic intervention. Adult-type diffuse low-grade gliomas are frequently associated with mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2), resulting in production of 2-hydroxyglutarate, an oncometabolite important for tumorigenesis. Recent studies of IDH inhibitors have yielded promising results in patients at early stages of disease with prolonged progression-free survival (PFS) and delayed time to radiation and chemotherapy. Pediatric-type gliomas have high rates of alterations in BRAF, including BRAF V600E point mutations or BRAF-KIAA1549 rearrangements. BRAF inhibitors, often combined with MEK inhibitors, have resulted in radiographic response and improved PFS in these patients. This article reviews emerging approaches to the treatment of low-grade gliomas, including a discussion of targeted therapies and how they integrate with the current treatment modalities of surgical resection, chemotherapy, and radiation.

MEK inhibition enhances the antitumor effect of radiation therapy in NF1-deficient glioblastoma.

Individuals with neurofibromatosis type 1 (NF-1), an autosomal dominant neurogenetic and tumor predisposition syndrome, are susceptible to developing low-grade glioma (LGG) and, less commonly, high-grade glioma (HGG). These gliomas exhibit loss of the neurofibromin gene (NF1), and 10-15% of sporadic HGG have somatic NF1 alterations. Loss of NF1 leads to hyperactive RAS signaling, creating opportunity given the established efficacy of MEK inhibitors (MEKi) in plexiform neurofibromas and some individuals with LGG. We observed that NF1-deficient glioblastoma neurospheres were sensitive to the combination of a MEKi (mirdametinib) with irradiation, as evidenced by synergistic inhibition of cell growth, colony formation, and increased cell death. In contrast, NF1-intact neurospheres were not sensitive to the combination, despite complete ERK pathway inhibition. No neurosphere lines exhibited enhanced sensitivity to temozolomide combined with mirdametinib. Mirdametinib decreased transcription of homologous recombination genes and RAD51 foci, associated with DNA damage repair, in sensitive models. Heterotopic xenograft models displayed synergistic growth inhibition to mirdametinib combined with irradiation in NF1-deficient glioma xenografts, but not those with intact NF1. In sensitive models, benefits were observed at least three weeks beyond the completion of treatment, including sustained phosphor-ERK inhibition on immunoblot and decreased Ki-67 expression. These observations demonstrate synergistic activity between mirdametinib and irradiation in NF1-deficient glioma models and may have clinical implications for patients with gliomas that harbor germline or somatic NF1 alterations.

Microvessel Density (MVD) in Patients with Osteosarcoma: A Systematic Review and Meta-Analysis.

A meta-analysis was designed and conducted to estimate the effect of tumoral microvessel density (MVD) on the survival of patients with osteosarcoma. There was no difference between high and low MVD regarding the overall (OS) and disease-free (DFS) survival. Low MVD tumors displayed a lower DFS at the third year of follow-up. Although primary metastases did not affect the mean MVD measurements, tumors with a good chemotherapy response had a higher MVD value. Although no significant differences between tumoral MVD, OS and DFS were found, good adjuvant therapy responders had a significant higher vascularization pattern.

A guideline on the molecular ecosystem regulating ferroptosis.

Ferroptosis, an intricately regulated form of cell death characterized by uncontrolled lipid peroxidation, has garnered substantial interest since this term was first coined in 2012. Recent years have witnessed remarkable progress in elucidating the detailed molecular mechanisms that govern ferroptosis induction and defence, with particular emphasis on the roles of heterogeneity and plasticity. In this Review, we discuss the molecular ecosystem of ferroptosis, with implications that may inform and enable safe and effective therapeutic strategies across a broad spectrum of diseases.

Driving factors of neuronal ferroptosis.

Ferroptosis is an oxidative form of iron-dependent cell death characterized by the accumulation of lipid peroxides on membranes. Iron and lipids containing polyunsaturated fatty acids are essential for this process. Ferroptosis is central to several neurological diseases and underlies the importance of balanced iron and polyunsaturated fatty acid metabolism in the brain, particularly in neurons. Here, we reflect on the potential links between neuronal physiology and the accumulation of iron and peroxidated lipids, the mechanisms neurons use to protect themselves from ferroptosis, and the relationship between pathogenic protein deposition and ferroptosis in neurodegenerative disease. We propose that the unique physiology of neurons makes them especially vulnerable to ferroptosis.

The Immunohistochemical Expression of REV-7 in Various Human Cancer Pathology Specimens: A Systematic Review.

The purpose of this systematic review is to summarize all existing evidence, regarding the immunohistochemical expression of REV-7 in different human cancer pathology specimens. Moreover, the association of REV-7 expression with disease severity (clinical course), patients' survival, prognosis, and response to various treatments, such as chemotherapy and irradiation, was investigated. Three databases (PubMed, Scopus, and Cochrane) were systematically screened, from inception to September 2, 2023, as suggested by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Only studies using immunohistochemical staining for REV-7 in paraffin-embedded cancer tissues were included. Nine studies met the inclusion criteria and were included in the final qualitative synthesis. All nine studies were retrospective and non-comparative ones. Selected studies reported immunohistochemical expression of REV-7 in different types of cancer, including testicular cancer, ovarian cancer, esophagus squamous cell carcinoma, prostate cancer, colorectal cancer, diffuse large B-cell lymphoma, breast cancer, lung cancer, and skin cancer. High REV-7 expression was associated with faster disease progression, resistance to available treatment options, and worse prognosis in the majority of included studies. These results indicate that immunohistochemical staining of REV-7 protein could potentially be used as a predictive tissue marker in certain cases. Promising results, arising from REV-7 inactivation experiments, render REV-7 targeting a potential therapeutic strategy for future cancer management, especially in the cases of chemoresistant or radioresistant disease.

Colistin Effects on Emphysematous Lung in an LPS-Sepsis Model.

Emphysema is prevalent in various respiratory diseases like Chronic Obstructive Pulmonary Disease (COPD) and cystic fibrosis. Colistin and vasoconstrictive drugs are crucial for treating these patients when diagnosed with sepsis in the ICU. This study examines colistin impact in ether-induced emphysematous septic and non-septic animals, focusing on lung pathophysiology and inflammatory responses, including IL-1ß, TNF-α, AMPK, caspase-3, cyclin-D1, and colistin levels in lung tissue. All animals exhibited significant emphysematous changes, accentuated by LPS-induced septic conditions, validating the emphysema model and highlighting the exacerbating effect of sepsis on lung pathology. Colistin, alone or with vasoconstrictive drugs, stimulated immune responses through increased inflammatory cell infiltration and the presence of lymphocytes, indicating potential immunomodulatory effects. Vasoconstriction did not alter the effects of colistin or sepsis but correlated with increased colistin levels in the lungs of septic animals. These observations suggest a potential interplay between vasoconstrictive drugs and colistin distribution/metabolism, leading to enhanced local concentrations of colistin in the lung microenvironment. The findings suggest the need for further investigations to optimize colistin and vasoconstrictive drug delivery in critically ill patients with lung pathologies. Understanding these complexities may guide more effective management of inflammatory responses and lung pathologies in these critical conditions.

Multifocal Tuberculosis Verrucosa Cutis: Case Report and Review of the Literature.

Cutaneous tuberculosis (TB) is still a major public health problem worldwide. Tuberculosis verrucosa cutis (TBVC) is a cutaneous form of exogenous TB caused by exogenous reinfection in previously sensitized individuals. TBVC typically presents as a unifocal condition. Multifocal cutaneous lesions without any other tubercular foci are extremely rare in exogenous TB and few cases are reported in the literature. We describe the first case of multifocal TBVC in an 81-year-old Greek man. In total, 14 cases of multifocal TBVC have been reported in the literature (8 males and 6 females), with mean age 47.64 years (SD = 20.75) and mean time to diagnosis of 9.69 years (SD = 15.31). Most cases (11/12) responded rapidly to treatment, implying the accuracy of diagnosis, while no one was reported to be immunocompromised. Finally, in 10 cases (71.4%), history of skin microtrauma was reported (related either to daily life habits or to professional praxis), confirming it as the main risk factor. The tuberculin skin test was positive in 10 cases and tissue culture for mycobacteria was negative in all cases. TBVC can present with multiple lesions, even in countries where TB prevalence is not high, especially in patients with history of skin abrasions. Prompt specialist assessment can expedite the establishment of diagnosis.

Study of Biological Behavior and Antimicrobial Properties of Cerium Oxide Nanoparticles.

(1) Background: An element that has gained much attention in industrial and biomedical fields is Cerium (Ce). CeO2 nanoparticles have been proven to be promising regarding their different biomedical applications for the control of infection and inflammation. The aim of the present study was to investigate the biological properties and antimicrobial behavior of cerium oxide (CeO2) nanoparticles (NPs). (2) Methods: The investigation of the NPs' biocompatibility with human periodontal ligament cells (hPDLCs) was evaluated via the MTT assay. Measurement of alkaline phosphatase (ALP) levels and alizarine red staining (ARS) were used as markers in the investigation of CeO2 NPs' capacity to induce the osteogenic differentiation of hPDLCs. Induced inflammatory stress conditions were applied to hPDLCs with H2O2 to estimate the influence of CeO2 NPs on the viability of cells under these conditions, as well as to reveal any ROS scavenging properties. Total antioxidant capacity (TAC) of cell lysates with NPs was also investigated. Finally, the macro broth dilution method was the method of choice for checking the antibacterial capacity of CeO2 against the anaerobic pathogens Porphyromonas gingivalis and Prevotella intermedia. (3) Results: Cell viability assay indicated that hPDLCs increase their proliferation rate in a time-dependent manner in the presence of CeO2 NPs. ALP and ARS measurements showed that CeO2 NPs can promote the osteogenic differentiation of hPDLCs. In addition, the MTT assay and ROS determination demonstrated some interesting results concerning the viability of cells under oxidative stress conditions and, respectively, the capability of NPs to decrease free radical levels over the course of time. Antimicrobial toxicity was observed mainly against P. gingivalis. (4) Conclusions: CeO2 NPs could provide an excellent choice for use in clinical practices as they could prohibit bacterial proliferation and control inflammatory conditions.

Association of Length of Stay With the Clinical Trajectory of Hospitalized Patients With Atrial Fibrillation: Staying Less Is More?

Data predicting the length of stay (LOS) in patients with concurrent atrial fibrillation (AF) are scarce. This study aimed to investigate the potential predictors for prolonged LOS and its prognostic value. In this observational post hoc analysis of the MISOAC-AF (Motivational Interviewing to Support Oral AntiCoagulation adherence in patients with non-valvular Atrial Fibrillation) randomized trial logistic regression analyses were conducted to identify the parameters associated with prolonged LOS (defined as >7 days according to diagnostic accuracy analyses). Kaplan-Meier and Cox regression analyses were performed to generate survival curves and adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs) for the primary end point of all-cause mortality and for the secondary end points during a median 3.7-year follow-up. Of the 1,057 patients studied, 462 (43.7%) were hospitalized for ≥7 days. Heart failure with reduced ejection fracture (aHR 1.75, 95% CI 1.17 to 2.63), permanent AF (aHR 1.72, 95% CI 1.29 to 2.31), history of coronary artery disease (aHR 2.32, 95% CI 1.59 to 3.39), and advanced or end-stage chronic kidney disease (aHR 1.54, 95% CI 1.15 to 2.06) were independently associated with prolonged hospitalization. Prolonged LOS was independently linked with increased all-cause mortality rates (aHR 1.68, 95% CI 1.25 to 2.26), cardiovascular mortality (aHR 1.92, 95% CI 1.36 to 2.72), major bleeding (aHR 3.07, 95% CI 1.07 to 8.78), and the composite outcome of cardiovascular death or rehospitalization (aHR 1.31, 95% CI 1.04 to 1.66). Each extra day of LOS was an independent predictor of all-cause mortality (aHR 1.03, 95% CI 1.02 to 1.04). Hospitalized patients with concurrent AF carry a substantial morbidity burden being prone to extended LOS. A jointed approach seems reasonable to reduce the LOS in patients with AF.

Direct Oral Anticoagulants: Navigating Through Clinical Challenges.

PURPOSE: Direct oral anticoagulants (DOACs) have been approved, for over a decade, by both European and American medicine agencies, for treatment and prevention of several cardiovascular conditions. Since then, an increasing amount of data has been added to the medical literature day by day, resulting in a dichotomy in selection of the appropriate agent, dosage, and duration of treatment for special populations with multiple comorbidities. Considering these issues, we have prepared a comprehensive review for the clinical practitioner, to optimize the DOAC utilization in clinical practice. METHODS: A thorough literature search and review was conducted, concerning mainly the last decade. Our review focused on the current guidelines and the most recently published studies in PubMed, Science Direct Scopus, and Google Scholar to date. CONCLUSION: The purpose of this study is to provide guidance for healthcare professionals for making proper decisions when confronted with clinical challenges. Nevertheless, further research is required to establish DOAC superiority in complicated cases, where there is clinical uncertainty.

Microvessel density in patients with gastrointestinal stromal tumors: A systematic review and meta-analysis.

BACKGROUND: Gastrointestinal stromal tumors (GISTs) are considered the most common mesenchymal tumors of the gastrointestinal tract. Microvessel density (MVD) constitutes a direct method of vascularity quantification and has been associated with survival rates in multiple malignancies. AIM: To appraise the effect of MVD on the survival of patients with GIST. METHODS: This study adhered to Systematic reviews and Meta-Analyses guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. Electronic scholar databases and grey literature repositories were systematically screened. The Fixed Effects or Random Effects models were used according to the Cochran Q test. RESULTS: In total, 6 eligible studies were identified. The pooled hazard ratio (HR) for disease free survival (DFS) was 8.52 (95%CI: 1.69-42.84, P = 0.009). The odds ratios of disease-free survival between high and low MVD groups at 12 and 60 mo did not reach statistical significance. Significant superiority of the low MVD group in terms of DFS was documented at 36 and 120 mo (OR: 8.46, P < 0.0001 and OR: 22.71, P = 0.0003, respectively) as well as at metastases rate (OR: 0.11, P = 0.0003). CONCLUSION: MVD significantly correlates with the HR of DFS and overall survival rates at 36 and 120 mo. Further prospective studies of higher methodological quality are required.

DENND2B activates Rab35 at the intercellular bridge, regulating cytokinetic abscission and tetraploidy.

Cytokinesis relies on membrane trafficking pathways regulated by Rabs and guanine nucleotide exchange factors (GEFs). During cytokinesis, the intercellular cytokinetic bridge (ICB) connecting daughter cells undergoes abscission, which requires actin depolymerization. Rab35 recruits MICAL1 to oxidize and depolymerize actin filaments. We show that DENND2B, a protein linked to cancer and congenital disorders, functions as a Rab35 GEF, recruiting and activating Rab35 at the ICB. DENND2B's N-terminal region also interacts with an active form of Rab35, suggesting that DENND2B is both a Rab35 GEF and effector. Knockdown of DENND2B delays abscission, leading to multinucleated cells and filamentous actin (F-actin) accumulation at the ICB, impairing recruitment of ESCRT-III at the abscission site. Additionally, F-actin accumulation triggers the formation of a chromatin bridge, activating the NoCut/abscission checkpoint, and DENND2B knockdown activates Aurora B kinase, a hallmark of checkpoint activation. Thus, our study identifies DENND2B as a crucial player in cytokinetic abscission.

Treatment of the CRND8 mouse model for cerebral amyloid angiopathy, exhibited increased levels of neuron specific enolase in brain tissue following long-term treatment with a modified C5a receptor agonist, accompanied by improved cognitive function.

Alzheimer's disease (AD) is an irreversible neurodegenerative disorder characterized by amyloid plaques, neurofibrillary tangles, and cerebral amyloid angiopathy (CAA). CAA is a condition manifesting as amyloid deposits in the cerebral vasculature, eventually leading to microhemorrhage. Here, we have treated the CRND8 mouse model with the C5a agonist (EP67) in order to observe the effects on cerebral amyloidosis, CAA, and hyperphosphorylated tau. EP67 attaches to the C5a receptor on phagocytes and stimulates the engulfment and digestion of fibrillar and prefibrillar amyloid while exhibiting minimal inflammation. Older CRND8 mice and their respective controls were treated with EP67 for a prolonged period of time. Following treatment, the CRND8 mice displayed improved spatial memory, while both amyloid deposition and tau hyperphosphorylation were found to be diminished.

Head and neck follicular lymphoma with marginal zone differentiation and BCL2 translocation t(14;18) in both nodular and extranodular sites: a case report with mini-review.

OBJECTIVE: Head and neck follicular lymphoma (FL) with marginal zone (MZ) differentiation is a rare high-risk B-cell composite variant that has been reported in nodular but not extranodular sites in the parotid glands. Here we summarize the literature on FL with MZ differentiation in head and neck nodular sites and describe a rare case of extranodular FL with MZ differentiation in the parotid gland. STUDY DESIGN: We examined both the germinal center and MZ components of the parotid and bone-marrow biopsies of a 65-year-old female histologically, immunohistochemically, and molecularly to identify B-cell, germinal center, and follicular dendritic cell markers. RESULTS: The immunohistochemical and molecular analysis provided evidence that the FL and the MZ components derived from the same B-cell clone with a similar BCL2/IGH t(14;18) translocation site. The differentiated cells in the MZ did not express germinal center markers BCL6 and CD10. Both the parotid and bone-marrow proliferative B cells showed BCL6, CD2O, and CD79a positivity. CONCLUSIONS: Head and neck FL with MZ differentiation can develop in both nodular and extranodular sites and is characterized by BCL2 translocation t(14;18). Although the mechanism of MZ differentiation is unclear, the characterization of this rare histopathologic phenomenon might be clinically important.