Metastasizing pleomorphic adenoma of the parotid gland: A common tumour with a very unusual presentation / Metástasis de adenoma pleomorfo de la glándula parótida: un tumor frecuente con una presentación muy poco habitual

Metastasizing pleomorphic adenoma is recognized as a subtype of pleomorphic adenoma in WHO classification 5th edition of salivary glands. The controversy pertaining to the entity is the benign features of the disease even at a metastatic site. We present a rare case of left recurrent pre-auricular swelling in a young male reported as metastasizing pleomorphic adenoma. A nineteen-year-old male presented with left preauricular swelling seven years ago which was diagnosed as pleomorphic adenoma and underwent complete excision of tumour. The tumour recurred twice – two and five years after the surgery. At the second recurrence, the level II neck dissection showed multiple encapsulated deposits of pleomorphic adenoma having similar morphology in the cervical soft tissue with no features of high-grade transformation. (AU)

La metástasis de adenoma pleomorfo está reconocida como un subtipo de adenoma pleomorfo según la clasificación de tumores de las glándulas salivales de la Organización Mundial de la Salud (OMS), 5ª edición. La controversia sobre la entidad se refiere a las características benignas de la enfermedad, incluso en lugares de metástasis. Presentamos un raro caso, en un varón de 19 años, de inflamación preauricular izquierda recurrente que se comunica como una metástasis de adenoma pleomorfo. El paciente presentó inflamación preauricular izquierda hace siete años, que se diagnosticó como adenoma pleomorfo, y se sometió a una resección completa del tumor, el cual presentó dos recidivas, dos y cinco años después de la cirugía. En la segunda recidiva, la resección a nivel II del cuello mostró múltiples depósitos encapsulados de adenoma pleomorfo de morfología similar en el tejido blando cervical, sin características de transformación de alto grado. (AU)

Chinese surgical robot-assisted surgery for parotid tumor: a case report.

Robotic surgery is known as the "third technological revolution" in the field of surgery, and is an important milestone in the development of modern surgery. However, our country's innovative surgical robot industry is still in its early stages, and it is only being utilized in certain surgical fields. To explore the effectiveness of the application of domestic surgical robot in oral and maxillofacial surgery, the author successfully completed a case of benign parotid tumor resection with the assistance of a domestic autonomous robot. The operation was successful, facial nerve function was preserved, and postoperative wound healing was good.

Mucoepidermoid microcarcinoma in the context of parotid gland cyst.

Mucoepidermoid carcinoma is a type of salivary gland cancer that can develop in the context of a parotid gland cyst. This type of tumor is composed of mucous, epidermoid, and intercalated cells, and usually presents as a slow-growing and painless mass. A parotid gland cyst is a condition in which a fluid-filled sac forms in the parotid gland. The tumor can be masked as it develops within the parotid cyst. A 45-year-old female patient presented with a suspect of benign neoplasm of the major salivary gland. She underwent partial right parotidectomy, which upon pathological analysis confirmed the diagnosis of mucoepidermoid microcarcinoma associated with parotid gland cysts. The patient did well and continues under regular follow-up with no further treatment.

Preoperative Direct Puncture Embolization of Castleman Disease of the Parotid Gland: A Case Report.

BACKGROUND: Castleman disease (CD) is an uncommon benign lymphoproliferative disease characterized by hypervascular lymphoid hyperplasia. We present a unique case of unicentric CD of the parotid gland treated by preoperative direct puncture embolization. CASE PRESENTATION: A 27-year-old female patient was admitted for a right neck mass. Ultrasound examination and MRI scan documented a hypervascular mass within the right parotid gland. Preoperative embolization was performed by direct puncture technique: a needle was inserted into the core of the mass under both ultrasound and fluoroscopic guidance and SQUID 12 was injected into the mass under fluoroscopic control, achieving a total devascularization. CONCLUSION: Preoperative direct puncture embolization was safe and effective and provides excellent hemostatic control during the surgical operation, limiting the amount of intraoperative bleeding.

Metastatic cutaneous squamous cell carcinoma accounts for nearly all squamous cell carcinomas of the parotid gland.

Primary squamous cell carcinoma of the parotid gland (pSCCP) has long been recognized as a separate entity and is included in the WHO classifications of salivary gland tumors. However, it is widely accepted among head and neck pathologists that pSCCP is exceptionally rare. Yet, there are many publications describing series of pSCCP and data from SEER and other cancer register databases indicate erroneously an increasing incidence of pSCCP. Importantly, pSCCP and metastatic (secondary) squamous cell carcinoma to the parotid gland (mSCCP) have nearly identical histological features, and the diagnosis of pSCCP should only be made after the exclusion of mSCCP. Moreover, all of the histological diagnostic criteria proposed to be in favor of pSCCP (such as, for example, dysplasia of ductal epithelium) can be encountered in unequivocal mSCCP, thereby representing secondary growth along preexistent ducts. Squamous cell differentiation has also been reported in rare genetically defined primary parotid carcinomas, either as unequivocal histological squamous features (e.g., NUT carcinoma, mucoepidermoid carcinoma), by immunohistochemistry (e.g., in NUT carcinoma, adamantinoma-like Ewing sarcoma, basal-type salivary duct carcinoma, mucoepidermoid carcinoma), or a combination of both. Another major issue in this context is that the International Classification of Diseases (ICD) coding system does not distinguish between primary or metastatic disease, resulting in a large number of patients with mSCCP being misclassified as pSCCP. Immunohistochemistry and new molecular biomarkers have significantly improved the accuracy of the diagnosis of many salivary gland neoplasms, but until recently there were no biomarkers that can accurately distinguish between mSCCP and pSCCP. However, recent genomic profiling studies have unequivocally demonstrated that almost all SCCP analyzed to date have an ultraviolet light (UV)-induced mutational signature typical of mSCCP of skin origin. Thus, mutational signature analysis can be a very useful tool in determining the cutaneous origin of these tumors. Additional molecular studies may shed new light on this old diagnostic and clinical problem. This review presents a critical view of head and neck experts on this topic.

Ewing's sarcoma of the parotid gland: A rare entity with review of the literature.

Background: Ewing's sarcoma is a rare malignant entity. Extraosseous Ewing's sarcoma (EES) of the head and neck region is a rare occurrence, and Ewing's sarcoma of the parotid gland is even rarer. To the best of our knowledge, we reported the first case of extraskeletal ES originating from the parotid gland in the Tunisian literature. Case report: We report a rare case of EES of the parotid gland in a 35-year-old female. She presented with left parotid tumefaction. Physical examination revealed solid and fixed mass associated with facial paralysis. Magnetic resonance imaging illustrated a left intra-parotid process occupying the entire gland measuring 42 mm infiltrating the masseter and pterygoid muscles. The patient had a total left parotidectomy with ipsilateral triangular lymph node dissection. The definitive pathological examination and the immunohistochemical staining confirmed a primary peripheral neuroectodermal tumor or PNET with the presence of a specific EWING/PNET-type translocation in 60% of the tumor cells. She had an adjuvant chemotherapy (four cycles of vincristine, doxorubicin, cyclophosphamide alternating with ifosfamide and etoposide) followed by external radiotherapy. Conclusion: A clinical and radiological follow-up by cervical MRI was done every 3 months and The 10-month follow-up showed no locoregional and distant recurrence.

Introduction: Le sarcome d'Ewing est une entité maligne rare. La localisation extra osseuse en particulier la région de la tête et du cou est caractérisée par son agressivité locorégionale. Nous rapportons le cas d'un sarcome d'Ewing de la parotide. A notre connaissance, il s'agit du premier cas rapporté dans la littérature tunisienne. Presentation du cas: Il s'agit d'une femme âgée de 35 ans qui a consulté initialement pour une tuméfaction au niveau de la glande parotide gauche. L'examen clinique a révélé une masse sous angulomandibulaire associée à une paralysie faciale périphérique gauche. Une IRM parotidienne a objectivé un processus intra-parotidien gauche occupant l'entièreté de la glande mesurant 42 mm mal limitée infiltrant modérément le muscle masséter et ptérygoïdiens. Le bilan d'extension était sans anomalie. La patiente a eu une parotidectomie gauche large avec un curage triangulaire homolatéral. L'examen anatomopathologique définitif et l'étude par hybridation in situ en fluorescence (FISH) ont confirmé la présence d'une translocation spécifique type EWING/PNET dans 60% des cellules tumorales. La patiente a été traitée par une chimiothérapie type VDC/IE (vincristine, doxorubicine, cyclophosphamide en alternance avec ifosfamide, et etoposide) suivie d'une radiothérapie externe. Un suivi clinique et radiologique trimestrielle n'a montré aucune récidive locorégionale ni à distance à ce jour soit à 10 mois de recul. Conclusion: Une surveillance clinique et radiologique trimestrielle a été faite et le contrôle à 10 mois n'a pas montré de récidive locorégionale ou à distance.

Acute Onset of Delayed Facial Nerve Paralysis After an Uncomplicated Total Parotidectomy for an Oncocytoma.

Facial nerve injury is one of the most substantial potential sequelae of parotid surgery. Pulling, stretching, and otherwise disturbing the facial nerve during parotid surgery can lead to post-surgical neural paresis and consequential deficits in facial movement. Furthermore, transection of the main facial nerve trunk or its branches, either purposeful or incidental, can lead to complete paralysis of the related facial musculature. Facial nerve injury is often diagnosed immediately post-operatively as evident by deficits in ipsilateral facial motion on examination of the patient in the recovery unit or, at most, by one week post-operatively. Although delayed onset facial nerve paralysis is seen in traumatic injury and otologic surgery, it is uncommon that facial nerve paralysis presents late after parotid surgery in the absence of hematoma development, viral reactivation, or secondary insult. Here, we present the case of a 70-year-old man developing a delayed acute onset of hemi-facial paralysis 12 days after right-sided total parotidectomy for an oncocytoma; a facial nerve examination done immediately post-operatively and at the one-week post-operative follow-up was found to be normal. The patient was treated with two courses of high-dose oral steroids with close-to-complete resolution.

Extra-oral, Non-mucosal Approach for Oncologic Resections of the Mandible: A Case Series.

Introduction: Malignant tumors afflicting the sub-condylar area and ascending ramus of the mandible without mucosal involvement are extremely rare. Traditional approaches such as lip-split-cheek flap and Visor flap would prove sub-optimal and excessive for such limited lesions and entail salivary contamination and mental nerve sacrifice. To circumvent these limitations, we developed a surgical approach that achieves wide, extra-oral exposure to the condyle and ascending ramus and permits controlled resection, affording protection to the facial nerve branches and mental nerve, while avoiding salivary contamination. Case Report: The main features of the approach include a pre-auricular skin crease incision extendable both ways, trans-parotid dissection with protection of facial nerve branches, and controlled bony resection. In all cases, monobloc resection was possible with preservation of the uninvolved facial nerve branches, avoidance of salivary contamination, and prompt healing. Conclusion: An extra-oral non-mucosal surgical approach is described for highly selected cases of mandibular resection.

Machine learning-based survival prediction nomogram for postoperative parotid mucoepidermoid carcinoma.

Parotid mucoepidermoid carcinoma (P-MEC) is a significant histopathological subtype of salivary gland cancer with inherent heterogeneity and complexity. Existing clinical models inadequately offer personalized treatment options for patients. In response, we assessed the efficacy of four machine learning algorithms vis-à-vis traditional analysis in forecasting the overall survival (OS) of P-MEC patients. Using the SEER database, we analyzed data from 882 postoperative P-MEC patients (stages I-IVA). Single-factor Cox regression and four machine learning techniques (random forest, LASSO, XGBoost, best subset regression) were employed for variable selection. The optimal model was derived via stepwise backward regression, Akaike Information Criterion (AIC), and Area Under the Curve (AUC). Bootstrap resampling facilitated internal validation, while prediction accuracy was gauged through C-index, time-dependent ROC curve, and calibration curve. The model's clinical relevance was ascertained using decision curve analysis (DCA). The study found 3-, 5-, and 10-year OS rates of 0.887, 0.841, and 0.753, respectively. XGBoost, BSR, and LASSO stood out in predictive efficacy, identifying seven key prognostic factors including age, pathological grade, T stage, N stage, radiation therapy, chemotherapy, and marital status. A subsequent nomogram revealed a C-index of 0.8499 (3-year), 0.8557 (5-year), and 0.8375 (10-year) and AUC values of 0.8670, 0.8879, and 0.8767, respectively. The model also highlighted the clinical significance of postoperative radiotherapy across varying risk levels. Our prognostic model, grounded in machine learning, surpasses traditional models in prediction and offer superior visualization of variable importance.

Pleomorphic Lipoma of the Parotid Gland: A Potential Cytological Pitfall.

Pleomorphic lipoma is an uncommon benign adipocytic tumor that arises from the subcutis. It has no risk of recurrence, metastasis or malignant transformation. The cytological findings of pleomorphic lipoma are often overdiagnosed as suspicious of malignancy owing to the pleomorphic morphology of the floret giant cells. We present a rare case of pleomorphic lipoma of the parotid gland which was misdiagnosed as a malignant tumor on fine needle aspiration cytology. Histopathological examination and positive expression for CD34 helped to arrive at the final diagnosis. Awareness about this rare entity will prevent overdiagnosis as a malignant tumor and unnecessary radical resections for this benign tumor.

Intraoperative Facial Nerve Involvement in Parotid Tumours - A Retrospective Analysis in a Tertiary Care Centre.

Purpose: The study aims to provide a comprehensive overview of the various malignant and benign parotid tumours and evaluate the predictive factors for intraoperative nerve involvement leading to facial palsy (FP). Methods: It is a single-centre retrospective analysis for reviewing the involvement of facial nerve in post- parotidectomy patients. The clinical database from January 2012 to December 2020 was included in the study with a follow-up period of a minimum of 2 years. To maintain homogeneity, all squamous cell carcinomas of level 2 nodes involving parotid or residual/recurrent disease of the oral cavity requiring parotid dissection were excluded. Results: A total of 248 patients (171 benign; 77 malignant) were evaluated with a mean age of 46.48 ± 10.76 years. The presence of malignancy increases the risk of FP (p = 0.027). 37 (14.92%) patients with FP were detected which included 34 with partial [32.35% in malignant; 62.16% in recurrent pleomorphic adenoma (RPA)] and 3 with total paralysis (66.67% in malignant; 33.33% in RPA). The recurrence of pleomorphic adenoma increases FP. While old age, larger size, hard fixed swelling with masseteric space (MS) infiltration appeared as risk factors for FP in malignant tumours (p = 0.047; p = 0.004; p < 0.00001 respectively). Conclusion: Tumour size, malignancy, hard fixed mass, masseteric space infiltration, recurrence, and age > 45yrs have been statistically significant predictive factors for intraoperative facial nerve involvement leading to FP. The study also revealed that FP occurred more commonly when there was concurrent involvement of both superficial and deep lobes but was not statistically significant.

Rapamycin alleviates irradiation-induced parotid injury by enhancing the whole gland homeostasis.

OBJECTIVES: Salivary gland injury is one of the most common complications of radiotherapy in head-and-neck cancers. This study investigated the mechanism by which rapamycin prevents irradiation (IR)-induced injury in the parotid glands. MATERIALS AND METHODS: Miniature pigs either received (a) no treatment (NT), (b) IR in the right parotid gland for 5 consecutive days (IR), or intraperitoneal administration of rapamycin (Rap) 1 h prior to IR (IR + Rap). Tissues were collected at three distinct time points (24 h, 4 weeks, and 16 weeks) after IR. Histological analyses, western blot, and real-time reverse transcriptase-polymerase chain reaction were performed to explore the mechanisms of IR-induced injury in the parotid gland. RESULTS: Rapamycin treatment maintained parotid salivary flow 16 weeks post-IR, preserved the number of acinar cells, and reduced parotid tissue fibrosis, as well as reduced apoptosis levels, decreased cleaved caspase-3 expression, and increased the Bcl-2/Bax ratio in the parotid glands. Autophagy marker LC3B was upregulated by rapamycin after IR, while P62 expression was downregulated. Rapamycin reduced the expression of pro-inflammatory factors and the mesenchymal tissue fibrosis following IR. CONCLUSIONS: Rapamycin maintains gland homeostasis after IR by decreasing apoptosis, reducing the expression of pro-inflammatory factors, and enhancing autophagy.

An ultrasound-based ensemble machine learning model for the preoperative classification of pleomorphic adenoma and Warthin tumor in the parotid gland.

OBJECTIVES: The preoperative classification of pleomorphic adenomas (PMA) and Warthin tumors (WT) in the parotid gland plays an essential role in determining therapeutic strategies. This study aims to develop and validate an ultrasound-based ensemble machine learning (USEML) model, employing nonradiative and noninvasive features to differentiate PMA from WT. METHODS: A total of 203 patients with histologically confirmed PMA or WT who underwent parotidectomy from two centers were enrolled. Clinical factors, ultrasound (US) features, and radiomic features were extracted to develop three types of machine learning model: clinical models, US models, and USEML models. The diagnostic performance of the USEML model, as well as that of physicians based on experience, was evaluated and validated using receiver operating characteristic (ROC) curves in internal and external validation cohorts. DeLong's test was used for comparisons of AUCs. SHAP values were also utilized to explain the classification model. RESULTS: The USEML model achieved the highest AUC of 0.891 (95% CI, 0.774-0.961), surpassing the AUCs of both the US (0.847; 95% CI, 0.720-0.932) and clinical (0.814; 95% CI, 0.682-0.908) models. The USEML model also outperformed physicians in both internal and external validation datasets (both p < 0.05). The sensitivity, specificity, negative predictive value, and positive predictive value of the USEML model and physician experience were 89.3%/75.0%, 87.5%/54.2%, 87.5%/65.6%, and 89.3%/65.0%, respectively. CONCLUSIONS: The USEML model, incorporating clinical factors, ultrasound factors, and radiomic features, demonstrated efficient performance in distinguishing PMA from WT in the parotid gland. CLINICAL RELEVANCE STATEMENT: This study developed a machine learning model for preoperative diagnosis of pleomorphic adenoma and Warthin tumor in the parotid gland based on clinical, ultrasound, and radiomic features. Furthermore, it outperformed physicians in an external validation dataset, indicating its potential for clinical application. KEY POINTS: • Differentiating pleomorphic adenoma (PMA) and Warthin tumor (WT) affects management decisions and is currently done by invasive biopsy. • Integration of US-radiomic, clinical, and ultrasound findings in a machine learning model results in improved diagnostic accuracy. • The ultrasound-based ensemble machine learning (USEML) model consistently outperforms physicians, suggesting its potential applicability in clinical settings.

Unicentric Castleman's disease in the parotid gland associated with psoriasis: a case report.

BACKGROUND: Castleman's disease is a rare lymphoproliferative disorder that is often misdiagnosed because of its untypical clinical or imaging features except for a painless mass. Besides, it is also difficult to cure Castleman's disease due to its unclear pathogenesis. CASE PRESENTATION: We present a Castleman's disease case with diagnostic significance regarding a 54-year-old Chinese male who has a painless mass in his left parotid gland for 18 months with a 30-years history of autoimmune disease psoriasis. Computed tomography scan showed a high-density nodule with clear boundaries in the left parotid and multiple enlarged lymph nodes in the left submandibular and neck region. General checkup, the extremely elevated serum interleukin-6 and lymph node biopsy in the left submandibular region gave us an initial suspicion of Castleman's disease. Then the patient underwent a left superficial parotidectomy. Based on histopathologic analysis, we made a certain diagnosis of Castleman's disease and gave corresponding treatments. In 18 months of follow-up, the patient showed no evidence of recurrence, with the level of serum interleukin-6 decreased. CONCLUSIONS: Clinicians should be aware of the possibility of Castleman's disease when faced with masses or enlarged lymph nodes in the parotid gland to avoid misdiagnosis, especially in patients with autoimmune diseases and elevated serum interleukin-6.

Factors influencing Frey syndrome after parotidectomy with acellular dermal matrix.

BACKGROUND: Frey syndrome, also known as ototemporal nerve syndrome or gustatory sweating syndrome, is one of the most common complications of parotid gland surgery. This condition is characterized by abnormal sensations in the facial skin accompanied by episodes of flushing and sweating triggered by cognitive processes, visual stimuli, or eating. AIM: To investigate the preventive effect of acellular dermal matrix (ADM) on Frey syndrome after parotid tumor resection and analyzed the effects of Frey syndrome across various surgical methods and other factors involved in parotid tumor resection. METHODS: Retrospective data from 82 patients were analyzed to assess the correlation between sex, age, resection sample size, operation time, operation mode, ADM usage, and occurrence of postoperative Frey syndrome. RESULTS: Among the 82 patients, the incidence of Frey syndrome was 56.1%. There were no significant differences in sex, age, or operation time between the two groups (P > 0.05). However, there was a significant difference between ADM implantation and occurrence of Frey syndrome (P < 0.05). ADM application could reduce the variation in the incidence of Frey syndrome across different operation modes. CONCLUSION: ADM can effectively prevent Frey syndrome and delay its onset.

Direct visualization of intraparotid facial nerve assisting in parotid tumor resection.

Precise recognition of the intraparotid facial nerve (IFN) is crucial during parotid tumor resection. We aimed to explore the application effect of direct visualization of the IFN in parotid tumor resection. Fifteen patients with parotid tumors were enrolled in this study and underwent specific radiological scanning in which the IFNs were displayed as high-intensity images. After image segmentation, IFN could be preoperatively directly visualized. Mixed reality combined with surgical navigation were applied to intraoperatively directly visualize the segmentation results as real-time three-dimensional holograms, guiding the surgeons in IFN dissection and tumor resection. Radiological visibility of the IFN, accuracy of image segmentation and postoperative facial nerve function were analyzed. The trunks of IFN were directly visible in radiological images for all patients. Of 37 landmark points on the IFN, 36 were accurately segmented. Four patients were classified as House-Brackmann Grade I postoperatively. Two patients with malignancies had postoperative long-standing facial paralysis. Direct visualization of IFN was a feasible novel method with high accuracy that could assist in recognition of IFN and therefore potentially improve the treatment outcome of parotid tumor resection.

Heterogeneous PSMA ligand uptake inside parotid glands.

The purpose of this investigation is to quantify the spatial heterogeneity of prostate-specific membrane antigen (PSMA) positron emission tomography (PET) uptake within parotid glands. We aim to quantify patterns in well-defined regions to facilitate further investigations. Furthermore, we investigate whether uptake is correlated with computed tomography (CT) texture features. METHODS: Parotid glands from [18F]DCFPyL PSMA PET/CT images of 30 prostate cancer patients were analyzed. Uptake patterns were assessed with various segmentation schemes. Spearman's rank correlation coefficient was calculated between PSMA PET uptake and feature values of a Grey Level Run Length Matrix using a long and short run length emphasis (GLRLML and GLRLMS) in subregions of the parotid gland. RESULTS: PSMA PET uptake was significantly higher (p < 0.001) in lateral/posterior regions of the glands than anterior/medial regions. Maximum uptake was found in the lateral half of parotid glands in 50 out of 60 glands. The difference in SUVmean between parotid halves is greatest when parotids are divided by a plane separating the anterior/medial and posterior/lateral halves symmetrically (out of 120 bisections tested). PSMA PET uptake was significantly correlated with CT GLRLML (p < 0.001), and anti-correlated with CT GLRLMS (p < 0.001). CONCLUSION: Uptake of PSMA PET is heterogeneous within parotid glands, with uptake biased towards lateral/posterior regions. Uptake within parotid glands was strongly correlated with CT texture feature maps.

Parotid hypersalivation after inferior salivatory nucleus glutamate/NMDA receptor excitation in the rat.

Although salivation is essential during eating behavior, little is known about the brainstem centers that directly control the salivary glands. With regard to the inferior salivatory nucleus (ISN), the site of origin of the parasympathetic preganglionic cell bodies that innervate the parotid glands, previous anatomical studies have located it within the rostrodorsal medullary reticular formation. However, to date there is no functional data that shows the secretory nature of the somas grouped in this region. To activate only the somas and rule out the activation of the efferent fibers from and the afferent fibers to the ISN, in exp. 1, NMDA neurotoxin was administered to the rostrodorsal medullary region and the secretion of saliva was recorded during the following hour. Results showed an increased secretion of parotid saliva but a total absence of submandibular-sublingual secretion. In exp. 2, results showed that the hypersecretion of parotid saliva after NMDA microinjection was completely blocked by the administration of atropine (a cholinergic blocker) but not after administration of dihydroergotamine plus propranolol (α and ß-adrenergic blockers, respectively). These findings suggest that the somata of the rostrodorsal medulla are secretory in nature, controlling parotid secretion via a cholinergic pathway. The data thus functionally supports the idea that these cells constitute the ISN.

Incidentally found parotid gland lesion in 18F-FDG PET/CT for staging evaluation of patients with hepatocellular carcinoma: remote possibility of metastatic tumor or second primary salivary gland malignancy.

OBJECTIVES: We primarily aimed to evaluate whether parotid incidental lesion (PIL) in 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for staging evaluation of patients with hepatocellular carcinoma (HCC) would represent a possibility of extrahepatic metastasis or second primary malignancy (SPM). Additionally, we explored the incidence of PIL in HCC patients and examined any associated risk factors. METHODS: We retrospectively analyzed patients with HCC who underwent 18F-FDG PET/CT at our institution from 2010 to 2022. The pathological findings of PILs in HCC patients were investigated for confirmatory identification of the risk of HCC metastasis or SPM in parotid gland. Healthy controls received 18F-FDG PET/CT for health screening were also enrolled to compare the incidence of PILs with HCC patients. Various parameters associated with patient demographics and characteristics of HCC were analyzed to find the related factors of PILs. RESULTS: A total of 17,674 patients with HCC and 2,090 healthy individuals who had undergone 18F-FDG PET/CT scans were enrolled in the analyses. Among the 54 HCC patients who underwent pathological confirmation for PILs, benign primary parotid tumor was most commonly observed (n = 43 [79.6%]); however, no malignant lesions were detected, including HCC metastasis. The incidence of PILs was higher in patients diagnosed with HCC compared with the control group (485 [2.7%] vs. 23 [1.1%], p = 0.002). Analysis for the risk factors for PILs revealed that patient age, sex, and positive viral markers were significantly associated with the incidence of PILs in patients with HCC (all p < 0.001). CONCLUSIONS: Our study demonstrates that PILs are more frequently identified in patients with HCC on 18F-FDG PET/CT. However, no malignant PIL, including extrahepatic metastasis of HCC, was identified. Therefore, the presence of PIL should not impede or delay the treatment process for patients with HCC. Additionally, we suggested that for future swift and straightforward differential diagnoses of PIL, the development of additional protocols within the PET/CT imaging could be beneficial.

Treatment of Warthin's Tumors of the Parotid Gland With Radiofrequency Ablation: A Systematic Review of the Current Literature.

Objective: Warthin's tumors of the parotid gland can be safely observed. Definitive treatment usually requires parotidectomy under general anesthesia. The decision to operate on Warthin's tumors of the parotid gland can be complicated in patients who wish to avoid risks of surgery and general anesthesia. This systematic review explores the potential of radiofrequency ablation (RFA) as a minimally invasive alternative. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) model was used to collect 3 relevant studies that focused on RFA treatment for Warthin's tumors. The cumulative averages for tumor size and cosmetic scores were then quantified for patients with Warthin's tumors who underwent RFA therapy. The PRISMA systematic review method was employed to the PubMed and EMBASE databases. The comprehensive search term "Warthin Tumor Treatment" yielded 1299 articles from the years 1955 to 2023, 3 of which met inclusion criteria and were then selected. Results: The 3 quantitative studies collectively assessed 37 patients with Warthin's tumors treated with RFA. Patients experienced an average tumor size reduction of 85.03% at 12 months post-RFA. There were minimal complications associated with RFA in these patients. Conclusion: This study suggests that RFA is an alternative to parotidectomy for the symptomatic treatment of Warthin's tumors. RFA procedures demonstrated substantial tumor size reduction with few complications. However, further meta-analysis and comparison with alternative treatments is warranted to establish RFA's role in treatment of Warthin's tumors. The study is limited by its reliance on only 2 databases and a lack of comprehensive examination of different RFA settings.