Exosome-mediated secretion of miR-127-3p regulated by RAB27A accelerates metastasis in renal cell carcinoma.

BACKGROUND: The exosome-mediated extracellular secretion of miRNAs occurs in many cancers, and RAB27A is a potent regulator of exosome secretion. For metastatic renal cell carcinoma (RCC), this study examines the mechanisms of cancer metastasis via the RAB27A-regulated secretion of specific miRNAs. METHODS: RAB27A knockdown (KD) and overexpressing (OE) RCC cells were used to examine cell migration and adhesion. The particle counts and sizes of exosomes in RAB27A OE cells were analyzed using Exoview, and those of intraluminal vesicles (ILV) and multivesicular bodies (MVB) were measured using an electron microscope. Analysis of RNA sequences, protein-protein interaction networks, and the competing endogenous RNA (ceRNA) network were used to identify representative downregulated miRNAs that are likely to undergo cargo-sorting into exosomes and subsequent secretion. A molecular beacon of miR-137-3p, one of the most representatively downregulated genes with a fold change of 339, was produced, and its secretion was analyzed using Exoview. RAB27A OE and control cells were incubated in an exosome-containing media to determine the uptake of tumor suppressor miRNAs that affect cancer cell metastasis. RESULTS: Migration and cell adhesion were higher in RAB27A OE cells than in RAB27A KD cells. Electron microscopy revealed that the numbers of multivesicular bodies and intraluminal vesicles per cell were higher in RAB27A OE cells than in control cells, suggesting their secretion. The finding revealed that miR-127-3p was sorted into exosomes and disposed of extracellularly. Protein-protein interaction analysis revealed MYCN to be the most significant hub for RAB27A-OE RCC cells. ceRNA network analysis revealed that MAPK4 interacted strongly with miR-127-3p. CONCLUSION: The disposal of miR-127-3p through exosome secretion in RAB27A overexpressing cells may not inhibit the MAPK pathway to gain metastatic potential by activating MYCN. The exosomes containing miRNAs are valuable therapeutic targets for cancer treatment.

PD-L1 and PD-1 Expression in Early Stage Uterine Endometrioid Carcinoma.

BACKGROUND/AIM: Immune checkpoint inhibitors (ICI) and tumor-infiltrating lymphocytes (TILs) for cancer treatment in clinical oncology have revolutionized patient care. However, no gold standard exists for the criteria of analytical validity of TILs of different types of cancer. MATERIALS AND METHODS: Clinicopathological data from 60 patients with endometrioid carcinoma (EC) who had undergone surgical treatment at the Gyeongsang National University Hospital between January 2002 and December 2009, were investigated. The programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PDL1) expression levels were characterized by immunohistochemical staining patterns, and the interpretations derived from machine learning morphometric analysis (Genie) and the pathologists' assessments were compared. In solid tumors, pathologists assessed the proportion of positive cells in each core of the tissue microarray. For Genie, the proportion of positive cells in the entire core and the number of positive cells per 1 mm2 were used. RESULTS: Both the pathologists and Genie identified the same trend in association with tumor size, with significant differences (p=0.026, p=0.033). Genie expression showed a significant association with PD1 expression, and pathologists identified a significant association with PDL1 expression in immune cells. CONCLUSION: The PD1 expression levels identified in immune cells of EC specimens were similar between the pathologists and Genie, suggesting that there is little resistance to the introduction of morphometric analysis. To our knowledge, this is the first study to introduce and validate machine learning as an integrated method for predicting prognosis and treatment based on PD1 expression in EC tumor microenvironments.

Perilipin1 Expression as a Prognostic Factor in Patients with Squamous Cell Carcinoma of the Lung.

Perilipin (PLIN) is a major structural protein located on the surface of lipid droplets. PLIN plays an important role in human metabolism and is associated with metabolic diseases, such as obesity, diabetes, hypertension, and endocrine disorders. The dysregulation of lipid metabolism is one of the most prominent metabolic changes observed in cancers. Therefore, the PLIN protein family has recently attracted attention owing to its role in lipid metabolism and cancer. To date, no studies have addressed the association between the prognosis of lung cancer and PLIN1 expression. For the first time, we found that high PLIN1 expression was significantly correlated with worse disease-free survival (DFS) in lung squamous cell carcinoma (SCC). We examined PLIN1 expression by the immunohistochemical analysis of surgical lung SCC specimens obtained from 94 patients. We analyzed the correlation between PLIN1 expression, clinicopathological data, and patient survival, using a chi-squared test, Kaplan-Meier analysis with log-rank tests, and the multivariate Cox proportional hazards regression test. High PLIN1 expression was significantly correlated with lower DFS in the Kaplan-Meier analysis and the multivariate Cox proportional hazards regression model. High PLIN1 expression was significantly correlated with worse prognosis in lung SCC.

High-Grade Surface Osteosarcoma of the Rib Mimicking a Neurogenic Tumor: Radiologic and Pathologic Findings.

Osteosarcoma commonly occurs in the intramedullary cavity of long bones such as the femur, tibia, and humerus in children and adolescents. Osteosarcoma occurring as a primary tumor in the chest wall is rare. Only a limited number of such cases have been documented in the existing literature. Herein, we present radiologic and pathologic findings of a high-grade surface osteosarcoma of the rib mimicking a neurogenic tumor in a 44-year-old woman.

Kikuchi-Fujimoto Disease in the Axilla after COVID-19 Vaccination: A Case Report.

BACKGROUND: Kikuchi-Fujimoto disease (KFD) is a rare, self-limiting inflammatory condition of unknown etiology that is characterized by fever and painful lymphadenopathy. KFD commonly involves the posterior cervical region and very rarely occurs in the axilla. CASE PRESENTATION: We report on a case of KFD that presented 3 weeks after receiving the messenger ribonucleic acid-based coronavirus disease 2019 (COVID-19) vaccine. In this case, we suspected the lesions as COVID-19 vaccination-related lymphadenopathy on the initial ultrasonographic examination. CONCLUSION: Through this case report, we highlight that KFD should be considered in the differential diagnosis of patients with axillary lymphadenopathy who have undergone COVID-19 vaccination, as unusual side effects of COVID-19 vaccination have been increasingly reported in the literature owing to the rapid development of various COVID-19 vaccines during the pandemic period. In addition, we emphasize the importance of clinical suspicion in diagnosing KFD due to the fact that axillary involvement of KFD is extremely rare.

IgA nephropathy with minimal change disease associated with primary Sjögren's syndrome: A case report.

RATIONALE: Only 1 case of IgA nephropathy (IgAN) with minimal change disease (MCD) associated with primary Sjögren's syndrome (SS) has been reported. We additionally describe IgAN with MCD associated with primary SS. PATIENT CONCERNS: A 80-year-old woman visited our hospital complaining of generalized edema that had started 4 weeks prior. She reported a sense of thirst and dry eye for the last 5 years. DIAGNOSES: Her initial laboratory findings were compatible with nephrotic syndrome; both the antinuclear antibody (1:80) and anti-SS-A (Ro) antibody (200 U/mL) tests were positive. A salivary gland scan revealed markedly decreased uptake for both the parotid and submandibular glands. The Schirmer test was positive. The random urine protein/creatinine ratio was 10 mg/mg. Renal biopsy was compatible with IgAN with superimposed MCD. INTERVENTIONS: Furosemide was intravenously administered with intermittent albumin infusion for her edema control. She was started on prednisone 40mg daily for 6 weeks, which was tapered to 5 mg for another 6 months after starting prednisolone. OUTCOMES: Over the next 6 months, her edema improved and the proteinuria decreased significantly. LESSONS: Physician should suspect IgA with MCD when patient with SS clinically showed nephrotic syndrome, and perform renal biopsy for pathologically diagnosis and appropriate treatment.

Impact of ACE2 and TMPRSS2 Expression in Patients With Preeclampsia.

BACKGROUND/AIM: As maternal morbidity and mortality during pregnancy have increased during the COVID-19 pandemic, studies on pregnancy-related complications from SARS-CoV-2 infection are being actively conducted. Considering that pregnant women with COVID-19 may develop a preeclampsia (PE)-like syndrome, it is necessary to differentiate it from PE because true PE can result in an unfavorable perinatal outcome during a hasty delivery. MATERIALS AND METHODS: We investigated the protein expression of transmembrane serine protease 2 (TMPRSS2) and angiotensin-converting enzyme 2 (ACE2) in placental samples from 42 normotensive (n=9) and PE (n=33) patients without SARS-CoV-2 infection. We isolated placental trophoblast cells from normotensive and PE patients without evidence of SARS-CoV-2 infection to determine the mRNA and protein expression levels of TMPRSS2 and ACE2. RESULTS: High ACE2 cytoplasmic expression in extravillous trophoblasts (EVTs) was correlated with lower fibrin deposition (p=0.017). In comparison with high nuclear TMPRSS2 expression, low nuclearTMPRSS2 expression in endothelial cells (ECs) was positively correlated with PE (p=0.005), significantly higher systolic blood pressure (p=0.006), and higher urine protein-to-creatinine ratio (p=0.022). In contrast, high cytoplasmic TMPRSS2 expression in fibroblasts (FBs) was correlated with higher urine protein-to-creatinine ratio (p=0.018). Trophoblast cells extracted from PE placental tissue showed lower mRNA levels for both ACE2 and TMPRSS2. CONCLUSION: TMPRSS2 nuclear expression in ECs and cytoplasmic expression in FBs of the placenta may be related to a trophoblast-independent PE mechanism, and TMPRSS2 could be a new biomarker to discriminate actual PE from a PE-like syndrome associated with COVID-19.

Airspace Enlargement with Fibrosis in a Young Heavy Smoker Mimicking Diffuse Cystic Lung Disease.

The widespread use of computed tomography (CT) has led to the increased recognition of cystic lung lesions. Multiple pulmonary cysts can be observed in heterogeneous disorders called diffuse cystic lung diseases (DCLDs), which include pulmonary Langerhans cell histiocytosis, lymphangioleiomyomatosis, lymphocytic interstitial pneumonia, and Birt-Hogg-Dubé syndrome. Recently, airspace enlargement with fibrosis (AEF) has been recognized as an entity on the spectrum of smoking-related lung diseases. We report a young male heavy smoker presenting diffuse pulmonary cysts on chest CT with suspected DCLD. However, histopathological examination of the surgical biopsy specimen revealed dilated emphysematous cysts with prominent mural fibrosis, consistent with AEF.

Fc Receptor Expression as a Prognostic Factor in Patients With Non-small-cell Lung Cancer.

BACKGROUND/AIM: The neonatal Fc receptor (FcRn) is a major histocompatibility class I-like molecule responsible for the transfer of passive humoral immunity from a mother to her newborn. Recent research revealed that FcRn is involved in antigen-presentation, humoral immunity and antitumor immunity of various types of cancer, such as lung, colon and breast. Lung cancer is the leading cause of cancer-related death and non-small cell lung cancer (NSCLC) accounts for 85% of all lung cancer. NSCLC is a highly heterogeneous disease and this affects the prognosis. Therefore, many studies have tried to identify factors that are associated with prognosis. The lungs are a major organ expressing FcRn. We aimed to evaluate FcRn expression in surgical specimens of NSCLC and determine its correlation with patient prognosis. MATERIALS AND METHODS: We analyzed 140 NSCLC surgical specimens for FcRn expression using immunohistochemistry and correlated positivity with clinicopathology and survival of these patients. A chi-squared test and Kaplan-Meier analysis with log-rank tests were performed for statistical evaluation. RESULTS: The FcRn-positive group had a significantly higher disease-free survival and a tendency towards increased disease-specific survival in patients with tumor-node-metastasis stage I NSCLC. CONCLUSION: Our study supports the hypothesis that FcRn down-regulation is associated with NSCLC progression.

Factors Associated with the Severity of Pregnancy-Related Hypertensive Disorder: Significance of Clinical, Laboratory, and Histopathological Features.

The purpose of this paper is to evaluate the association of maternal clinical and laboratory features and placental histopathological changes with disease severity in pregnancy-related hypertensive disorders. From January 2021 to December 2021, clinical and laboratory data at the time of delivery and histopathological features of the placenta were collected from pregnant women with pregnancy-related hypertensive disorders at a single institution. The women were classified according to the pregnancy-related hypertensive disorder clinical severity, and each variable was compared accordingly. Gestational age-matched normotensive groups were also compared. Univariate and multivariate regression analyses were used to identify factors influencing pregnancy-related hypertensive disorder severity. Fifty-eight pregnancies were analyzed. Maternal albumin levels before delivery (beta coefficient -0.83, p = 0.043) and increased placental syncytial knots (beta coefficient 0.71, p = 0.026) are important parameters that are closely related to disease severity in women with pregnancy-related hypertensive disorders. The combination of albumin, PAPP-A, total bilirubin, and eGFR levels appears to be optimal for predicting pregnancy-related hypertensive disorder severity.

RAB27A and RAB27B Expression May Predict Lymph Node Metastasis and Survival in Patients With Gastric Cancer.

BACKGROUND/AIM: RAB27A and RAB27B are involved in exosome secretion. To date, there have been many attempts to elucidate the roles of RAB27A and RAB27B in the prognosis of various cancer types. The association of RAB27A and RAB27B expression with the clinical and pathological features was evaluated in patients with stomach cancer. MATERIALS AND METHODS: A total of 360 patients who had undergone surgery for stomach cancer between January 1999 and December 2007 at Gyeongsang National University were enrolled in the study. Disease-free survival (DFS) and disease-specific survival (DSS) were compared according to immunohistochemistry of tumor samples. RAB27A and RAB27B mRNA and protein were also extracted from four stomach cancer cell lines using quantitative polymerase chain reaction and western blotting. RESULTS: Strong nuclear RAB27A expression in tumor samples was statistically significantly correlated with lymph node metastasis. Cytoplasmic RAB27B expression was related to poor disease-free survival and its combined cytoplasmic and membranous expression was related to disease-specific survival of patients with different histopathological types of stomach cancer. High RAB27A expression and high RAB27B expression was found in four stomach cancer cell blocks. Among the four cell lines, NCI-N87 exhibited the lowest relative mRNA density and HS746T exhibited the highest relative protein density for both RAB27A and RAB27B. CONCLUSION: RAB27A and RAB27B expression may help predict lymph node metastasis and survival of patients with gastric cancer.

Quantitative analysis of exosomes in the aqueous humor of Korean patients with pseudoexfoliation glaucoma.

We aimed to quantitatively analyze the exosome and its cargo in individual aqueous humor (AH) samples from pseudoexfoliation (PEX) glaucoma patients compared to controls using a novel detection platform. We investigated the size distribution and measured the quantitative exosome particle counts in each AH sample. AH (80-120 µL) was obtained during cataract surgery or glaucoma filtering surgery from 12 Korean subjects (six with PEX glaucoma and six age-matched controls). The mean size of the exosomes was 58.9 ± 18.5 nm measured by a tangential flow filtration system using single-particle interferometric reflectance imaging sensor. Exosome particle count in each CD 63, CD 81, and CD9 spot was significantly greater in PEX glaucoma than in controls in total, CD 63, CD9, syntenin, and scattering(all p < 0.003). The CD63 spot showed a particle count of 8319.1 ± 797.7 in PEX glaucoma patients and 4786.8 ± 1302.1 in controls (p = 1.88E-11). Individual fluorescent capture spot images also revealed denser exosome particles in PEX patients than in controls. Syntenin, indicating exosomal origin, was detected in all AH samples. Exosomes differentially detected in AH suggest the possible role of exosomes in the pathogenesis of PEX glaucoma.

Correlation between myoferlin expression and lymph node metastasis in papillary thyroid carcinoma.

BACKGROUND: Myoferlin is a multifunctional protein expressed in various normal and cancer cells, with novel oncogenic roles being newly discovered. Recently, correlations have been found between myoferlin expression and unfavorable prognosis in various carcinomas. This study investigated the prognostic role of myoferlin expression in papillary thyroid carcinoma (PTC), specifically that associated with nodal metastasis. METHODS: We collected clinicopathological data and PTC tissues from 116 patients who had been admitted to Gyeongsang National University Hospital in 2010. Immunohistochemical analysis was performed on surgical specimen-derived tissue microarray blocks. Myoferlin expression was graded, and the relationship between expression level and pathological features of tumors based on the American Joint Committee on Cancer staging system was evaluated. RESULTS: Of the 116 patient samples, 100 cases exhibited positive myoferlin expression. Higher grade of myoferlin expression was correlated with lower T category group (p = .010). Presence of lymph node metastasis was determined to be significantly correlated with low-grade myoferlin expression (p = .019), with no significant difference between pN1a and pN1b tumors. CONCLUSIONS: Our study revealed an adverse correlation between myoferlin expression and pathological features of PTC, evidence of the potential prognostic role of myoferlin in PTC lymph node metastasis.

Significance of HER2 and VEGFR2 in Early-stage Endometrial Cancer.

BACKGROUND/AIM: The majority of patients with early-stage endometrial cancer (EC) have a good prognosis, but recurrence does occur despite diagnosis at an early stage. There is a growing need for early diagnosis of EC and novel treatment options. MATERIALS AND METHODS: Human epidermal growth factor receptor 2 (HER2) and vascular endothelial growth factor receptor 2 (VEGFR) expression in microarrays of patient EC tissue was examined in association with clinicopathological data. HER2 and VEGFR2 expression in Ishikawa cells and differences in migration and proliferation of cells with HER2-knockdown were evaluated. RESULTS: Higher expression of VEGFR2 was associated with lower International Federation of Obstetrics and Gynecology grades (p=0.044). The positive correlation between HER2 and VEFR2 expression was statistically significant in T1 stage (p=0.002) and International Federation of Obstetrics and Gynecology grade 1 tumors (p=0.004). Wound-healing assays revealed that HER2 loss in Ishikawa cells reduced confluence compared to that of control cells. CONCLUSION: The association of VEGFR2 and HER2 expression in early EC was elucidated. This study shows that the measurement of VEGFR2 expression may be useful in the preoperative assessment of EC and suggests the possibility of anti-HER2 therapy for EC.

Clinical experience of tensor-valued diffusion encoding for microstructure imaging by diffusional variance decomposition in patients with breast cancer.

Background: Diffusion-weighted imaging plays a key role in magnetic resonance imaging (MRI) of breast tumors. However, it remains unclear how to interpret single diffusion encoding with respect to its link with tissue microstructure. The purpose of this retrospective cross-sectional study was to use tensor-valued diffusion encoding to investigate the underlying microstructure of invasive ductal carcinoma (IDC) and evaluate its potential value in a clinical setting. Methods: We retrospectively reviewed biopsy-proven breast cancer patients who underwent preoperative breast MRI examination from July 2020 to March 2021. We reviewed the MRI of 29 patients with 30 IDCs, including analysis by diffusional variance decomposition enabled by tensor-valued diffusion encoding. The diffusion parameters of mean diffusivity (MD), total mean kurtosis (MKT), anisotropic mean kurtosis (MKA), isotropic mean kurtosis (MKI), macroscopic fractional anisotropy (FA), and microscopic fractional anisotropy (µFA) were estimated. The parameter differences were compared between IDC and normal fibroglandular breast tissue (FGBT), as well as the association between the diffusion parameters and histopathologic items. Results: The mean value of MD in IDCs was significantly lower than that of normal FGBT (1.07±0.27 vs. 1.34±0.29, P<0.001); however, MKT, MKA, MKI, FA, and µFA were significantly higher (P<0.005). Among all the diffusion parameters, MKI was positively correlated with the tumor size on both MRI and pathological specimen (rs=0.38, P<0.05 vs. rs=0.54, P<0.01), whereas MKT had a positive correlation with the tumor size in the pathological specimen only (rs=0.47, P<0.02). In addition, the lymph node (LN) metastasis group had significantly higher MKT, MKA, and µFA compared to the metastasis negative group (P<0.05). Conclusions: Tensor-valued diffusion encoding enables a useful non-invasive method for characterizing breast cancers with information on tissue microstructures. Particularly, µFA could be a potential imaging biomarker for evaluating breast cancers prior to surgery or chemotherapy.

Cavernous Hemangioma of the Maxillary Sinus Masquerading Recurrent Hemorrhagic Mass: Histological-Radiological Correlation and a Literature Review.

BACKGROUND: Sinonasal cavernous hemangioma is rare. To date, fewer than 20 cases have been reported in the literature; however, they may be a source of recurrent epistaxis and masquerade of a hemorrhagic mass on CT and MRI. CASE REPORT: A 68-year-old woman was presented with recurrent epistaxis and progressive right malar fullness. On rhinoscopy, a bulge lesion was observed with multifocal hemorrhagic and friable surfaces in the right nasal cavity. CT and MRI demonstrated a well-defined mass in the right maxillary sinus with inhomogenous T2 hyperintensity, hypointense septa, peripheral rim, and multiple papillary enhancement, suggesting a recurrent hemorrhagic mass. The mass was excised endoscopically, and the histologic diagnosis was cavernous hemangioma. CONCLUSION: Imaging studies, such as CT and MRI, are essential in making an accurate diagnosis of cavernous hemangioma of the maxillary sinus. Endoscopic excision of the lesion can be curative.

Classification of subtypes including LCNEC in lung cancer biopsy slides using convolutional neural network from scratch.

Identifying the lung carcinoma subtype in small biopsy specimens is an important part of determining a suitable treatment plan but is often challenging without the help of special and/or immunohistochemical stains. Pathology image analysis that tackles this issue would be helpful for diagnoses and subtyping of lung carcinoma. In this study, we developed AI models to classify multinomial patterns of lung carcinoma; ADC, LCNEC, SCC, SCLC, and non-neoplastic lung tissue based on convolutional neural networks (CNN or ConvNet). Four CNNs that were pre-trained using transfer learning and one CNN built from scratch were used to classify patch images from pathology whole-slide images (WSIs). We first evaluated the diagnostic performance of each model in the test sets. The Xception model and the CNN built from scratch both achieved the highest performance with a macro average AUC of 0.90. The CNN built from scratch model obtained a macro average AUC of 0.97 on the dataset of four classes excluding LCNEC, and 0.95 on the dataset of three subtypes of lung carcinomas; NSCLC, SCLC, and non-tumor, respectively. Of particular note is that the relatively simple CNN built from scratch may be an approach for pathological image analysis.

Long noncoding RNAs associated with nonalcoholic fatty liver disease in a high cholesterol diet adult zebrafish model.

The mechanism of nonalcoholic fatty liver disease (NAFLD) has not been completely revealed. In this study, we investigated the association of liver histological changes and long noncoding RNAs (lncRNAs) in the NAFLD zebrafish model. Forty zebrafish were fed a high-cholesterol diet (1.5 g per day) for 8 weeks. We measured fatty liver changes in the zebrafish liver using oil red O staining and divided them into two groups based on high and low scores. We pooled each group of zebrafish livers and identified lncRNAs, miRNAs, and mRNAs using Next-generation sequencing. Human homologs of lncRNAs were identified using ZFLNC, Ensembl, and NONCODE. We found several significant genes, including 32 lncRNAs, 5 miRNA genes, and 8 protein-coding genes, that were associated with liver metabolism and NAFLD-related functions in zebrafish. In particular, eight conserved human homologs of lncRNAs were found. We discovered the human homologs of eight lncRNA candidates from fatty liver zebrafish for the first time. The spectrum of biological mechanisms by which lncRNAs mediate their functional roles in NAFLD in a high cholesterol diet adult zebrafish model remains to be uncovered.

MALT Lymphoma of the Tongue in a Patient with Sjögren's Syndrome: A Case Report and Literature Review.

Sjögren's syndrome (SS) is a systemic chronic autoimmune disorder characterized by lymphocytic infiltration of the exocrine glands, as well as oral and ocular dryness. Among the late complications, malignant lymphoma is the most serious complication of SS. The risk of lymphoma in patients with SS has been estimated to be approximately 7-19 times higher than that in a generally healthy population. Although various histologic subtypes of lymphoma can occur in patients with SS, mucosa-associated lymphoid tissue (MALT) lymphoma accounts for 48-75% of malignant lymphomas that are frequently located in the parotid gland. However, MALT lymphoma affecting the tongue in patients with SS is extremely rare. Here, we share our experience with a unique case of MALT lymphoma of the tongue, originating from the minor salivary gland tissue in a patient with SS. Through this case report, we emphasize that MALT lymphoma should be considered in the differential diagnosis of a tongue mass in patients with SS.

Prevalence and Clinical Implications of Incidentally Detected Parotid Lesions as Blind Spot on Brain MRI: A Single-Center Experience.

Background and objective: This study was conducted to assess the prevalence and clinical implications of parotid lesions detected incidentally during brain magnetic resonance imaging (MRI) examination. Materials and Methods: Between February 2016 and February 2021, we identified 86 lesions in the brain MRI reports of 84 patients that contained the words "parotid gland" or "PG". Of these, we finally included 49 lesions involving 45 patients following histopathological confirmation. Results: Based on the laboratory, radiological or histopathological findings, the prevalence of incidental parotid lesions was low (1.2%). Among the 45 study patients, 41 (91.1%) had unilateral lesions, and the majority of the lesions were located in the superficial lobe (40/49, 81.6%). The mean size of the parotid lesions was 1.3 cm ± 0.4 cm (range, 0.5 cm-2.8 cm). Of these, 46 parotid lesions (93.9%) were benign, whereas the remaining three lesions were malignant (6.1%). Conclusions: Despite the low prevalence and incidence of malignancy associated with incidental parotid lesions detected on brain MRI, the clinical implications are potentially significant. Therefore, clinical awareness and appropriate imaging work-up of these lesions are important for accurate diagnosis and timely management.