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.

Lacrimal gland pleomorphic adenoma: a narrative review / Adenoma pleomórfico de glândula lacrimal: uma revisão narrativa

ABSTRACT We present a literature review of 57 publications describing this pathology, published from the year 2012. In all these studies patients were reported to depict a slow-growing, motionless mass, which is painless at most times. All cases were managed by total excision, except for one report where adjuvant radiotherapy was applied. Among the several therapeutic strategies, the total tumor resection, preserving the tumor pseudocapsule intact, appears to be a consensus in treating the disease efficiently. Furthermore, fine-needle aspiration biopsy, including the assessment of genetic alterations, has proved to be a valuable tool in the diagnosis of challenging cases. Our literature survey also suggests that an incisional biopsy before the surgery may lead to the pseudocapsule disruption, thus considerably increasing the chances of adenoma recurrence, enabling its malignization. At present, genetics studies indicate that the molecular aberrations involved in the adenoma are similar to those represented in the salivary gland tumor pathogenesis. Further, in the recurrent cases, the pathology becomes difficult to treat and multiple surgeries may be required, occasionally, leading to radical surgery treatment.

RESUMO Uma revisão narrativa da literatura de 57 publicações que descrevem esta patologia, publicada a partir de 2012. Os pacientes têm uma massa de crescimento lento e imóvel, que na maioria das vezes é indolor. Todos os casos foram tratados por excisão total, com exceção de um relatório de radioterapia adjuvante. Entre as estratégias terapêuticas encontradas, a ressecção total do tumor, preservando a pseudocápsula tumoral intacta, parece ser um consenso. Alternativamente, a biópsia por aspiração de agulha fina incluindo a avaliação de alterações genéticas pode representar uma ferramenta valiosa nos casos diagnósticos desafiadores. Uma biópsia incisional antes da cirurgia não é recomendada, pois a ruptura da pseudocápsula aumenta consideravelmente a recorrência do adenoma, permitindo até mesmo sua malignização. Com relação à genética, estudos atuais indicam que as aberrações moleculares envolvidas no adenoma são semelhantes às da patogênese do tumor da glândula salivar. Para casos de recorrência, a patologia torna-se difícil de tratar e múltiplas cirurgias podem ser necessárias, às vezes levando a um tratamento cirúrgico radical.

Clinical behavior of recurrent pleomorphic adenoma in the palate: a systematic review

Purpose: This systematic review analyzed the clinical behavior and odds of malignancy of the palatal recurrent pleomorphic adenomas. Methods: Systematic review of patients with recurrent pleomorphic adenoma arising in the palate. Database search: MEDLINE, Scopus, Web of Science, Cochrane, EMBASE, Virtual Health Library, Google Scholar, and OpenGrey. A binomial logistic regression was performed to assess the odds of detecting recurrence five, 10 and 20 years after the treatment of primary tumor. Results: Thirteen studies (n = 18 patients) out of 336 were included. The recurrent pleomorphic adenoma in palate was more common in females (61.6%), average age was 49 years old (range 9-73 years old). Four patients progressed to malignant transformation. The odds ratio (OR) of detecting a recurrence at 10 (OR = 5.57; 95% confidence interval - 95%CI 1.13-27.52), and 20 years (OR = 18.78; 95%CI 3.18-110.84) after treatment of primary pleomorphic adenoma was significantly higher than at one-year follow-up. Conclusions: The recurrence of pleomorphic adenoma in palate remains a rare event of late occurrence. It mainly affects middle-aged female and carries a risk of malignant transformation. Although uncommon, patients with palatal pleomorphic adenoma should be warned about the possibility of recurrence or malignant transformation of tumor at advanced ages.

EZH2 immunoexpression in pleomorphic adenoma and adenoid cystic carcinoma and clinicopathological features

Abstract The aim of this study was to evaluate the expression of the EZH2 protein and describe the clinical and microscopic characteristics of adenoid cystic carcinoma (ACC) and pleomorphic adenoma (PA). The study included 16 ACC cases and 12 PA. All ACC and PA cases were positive for EZH2 and the ACC samples showed significantly higher EZH2 expression. The clinical and microscopic covariates were described in relation to EZH2 staining in ACC samples. The highest mean values of EZH2 were observed in cases with local metastasis, recurrence, perineural invasion, and predominantly cribriform growth pattern without solid areas. EZH2 is a potential marker of malignancy.

Influence of p16 Protein Immunostaining on Histopathological Features of Pleomorphic Adenoma and Carcinoma ex- Pleomorphic Adenoma.

The objective of this study was to evaluate the role of p16 in histologic characteristics and transition of Pleomorphic Adenoma (PA) to Carcinoma ex-PA (CxPA). So, 60 PA and 4 CxPA were histologic reviewed based on microscopic characteristics proposed by Hellquist, Triantafyllou and Dulguerov (PA) and Morais, Antony and Toluie (CxPA). Immunostaining for p16 was associated in different parenchyma and stroma of both tumors and Fisher's/chi-square tests and Mann-Whitney test were performed (SPSS v20.0, p<0.05). In PA the periductal cells were predominantly p16- and that ductal and myoepithelial cells showed a significant increase in p16+ cells (p<0.001). In CxPA, none of the cases showed p16+ in periductal cells, most parotid cases showed p16+ in ductal cells, and one case of parotid and the submandibular case showed mild immunostaining for myoepithelial cells. There was a small reduction in p16+ in CxPA compared to PA (p=0.537), but in both tumors there was less p16+ cells in solid stroma than other (p<0.001). The p16+ cases of PA had a higher capsular thickness (p=0.047). So, the loss of p16 immunostaining does not seem to be associated with the transition from PA to CxPA, but in both tumors the loss of p16+ cells are related to microscopic aggressiveness.

Evaluation of Mast Cell Density in Mucoepidermoid Carcinoma and Pleomorphic Adenoma.

Statement of the Problem: Mast cells are round to elliptical cells that originate from bone marrow stem cells and enter the peripheral blood. By releasing inflammatory mediators, these cells are involved in type I hypersensitivity, wound healing, defense against pathogens, increased blood vessel formation, and destruction of the extracellular matrix. There are contradictory results regarding the role of mast cells in tumor lesions. Purpose: Considering the contradictory results and few studies on the density of mast cells in salivary tumors, the present study investigated and compared the density of mast cells in two common salivary gland tumors. Materials and Method: In the cross-sectional study after reviewing the records of patients referred to the Pathology Department of the School of Dentistry and Shahid Sadoughi Hospital in Yazd, 15 blocks of each of the mucoepidermoid carcinoma and pleomorphic adenoma tumors were taken. After Giemsa staining of the samples, the average of stained cells in 10 random fields under 400× magnification was counted. The results were analyzed using statistical tests of t-test, ANOVA, Chi-square, and Mann-Whitney in SPSS ver. 22. Results: The average mast cell counts in pleomorphic adenoma (4.2) was higher than muco-epidermoid carcinoma (1.7) but there was no significant relationship (p= 0.305). In mucoepidermoid carcinoma, the numbers of mast cells increased with increasing tumor grade (low: 0/467 moderate: 1/567 high: 2/983) and there was a significant relationship (p= 0.009). Conclusion: According to the results of the present study, it seems that the mast cells accumulation may be secondarily associated with inflammatory responses due to cell accumulation and tissue destruction by tumor cells.

Oral rehabilitation after partial maxilectomy for removal of pleomorphic adenoma: case report / Reabilitação oral após maxilectomia parcial para remoção de adenoma pleomórfico: relato de caso

ABSTRACT Salivary gland tumors account for only 3%-5% of all tumors in the head and neck, 10%-15% of which originate from minor salivary glands. Pleomorphic adenoma is a benign lesion of the salivary gland, most commonly occurring in the region of the hard and soft palates. The treatment of choice for pleomorphic adenomas is with the partial or total function of the extension of the lesion, and placing palatal obturators are one method of reestablishing masticatory function and facial esthetics. This study aimed to rehabilitate a patient using a palatal implant following partial maxillectomy for the removal of a pleomorphic adenoma. A young patient with pleomorphic adenoma of the hard palate underwent a partial right-sided maxillectomy procedure which removed the hard palate and alveolar regions of the molars. Prior to surgery, the patient was assessed to make a surgical guide for resection of the tumor, as well as a provisional obturator plate using orthodontic wire clasps. After healing, the patient was rehabilitated using a palatal obturator which had been incorporated into a removable partial denture. The clinical sequence used to fabricate the final prosthesis was as follows: initial molding after surgery, prosthesis design, preparation of the mouth, work molding, structure testing and orientation planning, teeth testing and installation, and periodic maintenance. Thus, we can conclude that the palatal obturator is an excellent means of restoring a patient's oral function, facial esthetics, and overall quality of life.

RESUMO Os tumores de glândulas salivares representam apenas 3%-5% de todos os tumores em região de cabeça e pescoço, dentre eles 10%-15% se originam de glândulas salivares menores. O adenoma pleomórfico é uma lesão benigna de glândula salivar, tendo uma maior prevalência em região de palato. O tratamento dessas lesões se dá por método excisional ou maxilectomia dependendo da extensão da lesão e, uma das formas de reestabelecimento da estética e função do paciente é com um obturador palatino. O objetivo deste trabalho foi relatar uma reabilitação oral através da utilização de um obturador palatino em um paciente submetido a maxilectomia parcial para remoção de adenoma pleomórfico. Paciente de 22 anos, com adenoma pleomórfico em região de palato, foi submetido a maxilectomia parcial, removendo região de palato duro e região alveolar dos molares do lado direito. Foi realizada moldagem da maxila previamente a cirurgia para confecção de um guia cirúrgico, o guia foi utilizado na ressecção do tumor e, serviu também, para confecção de uma placa obturadora provisória associada a fios ortodônticos. Após cicatrização completa, foi acordado que a reabilitação do paciente seria com uma prótese parcial removível do tipo obturador palatino. A sequência clínica para a realização da prótese foi: moldagem inicial após a cirurgia, delineamento, preparo de boca, moldagem de trabalho, prova da infraestrutura e plano de orientação, prova dos dentes, instalação e manutenções periódicas. Com isso, podemos concluir que o obturador palatino é um excelente meio de reestabelecer função e estética do paciente, melhorando sua qualidade de vida.

Siringoma condroide: apresentação incomum de tumor raro / Chondroid syringoma: unusual presentation of a rare tumor

O siringoma condroide, também conhecido como tumor misto cutâneo, é uma neoplasia benigna rara, originada das glândulas sudoríparas, composta por estruturas epiteliais imersas em um estroma mixocondroide. Geralmente, apresenta-se como tumor sólido, único, localizado em face ou pescoço, com evolução crônica e assintomática. Relata-se caso de mulher, 75 anos, com lesão discretamente elevada na fronte, cujo diagnóstico foi definido pela análise histopatológica.

Chondroid syringoma, also known as a cutaneous mixed tumor, is a rare benign neoplasm originating from the sweat glands, composed of epithelial structures immersed in a myxochondroid stroma. It usually presents as a solid, single tumor located on the face or neck with a chronic and asymptomatic course. We report the case of a 75-year-old woman with a slightly elevated lesion on the forehead, whose diagnosis was defined by histopathological analysis.

Myotonic dystrophy and recurrent pleomorphic adenomas: Case report and association hypothesis.

We report a case of a patient with concurrent myotonic dystrophy and recurrent pleomorphic adenoma and hypothesize the association between both diseases. A 58-year-old man with classic myotonic dystrophy type 1 was diagnosed with pleomorphic adenoma. Appropriate treatment was commenced. Massive recurrences occurred within 15, 28 and 22 months respectively, after repeated surgical removal. Three case reports on similar occurrences of synchronous myotonic dystrophy and pleomorphic adenoma are discussed and an association between both disease entities is hypothesized. A conceivable association between myotonic dystrophy and pleomorphic adenoma is hypothesized by upregulation of the Wnt/Beta-catenin signaling pathway, initiated by a decreased expression of microRNA, pleomorphic adenoma gene 1 induced Beta-catenin accumulations and alterations in tumor suppressor genes and oncogenes due to RNA processing defects induced by the expanded repeat in the DMPK gene.

Amide proton transfer (APT) imaging of parotid tumors: Differentiation of malignant and benign tumors.

PURPOSE: To assess the usefulness of amide proton transfer (APT) imaging in differentiating parotid tumors. MATERIAL AND METHODS: We retrospectively analyzed 43 histopathologically proven parotid solid tumors with diameters ≥2 cm. Twenty-one tumors were benign and 12 tumors were malignant. Two-dimensional APT imaging was performed using a saturation pulse with a duration of 2 s and a saturation power level of 2 µT. For acquiring Z-spectra, the imaging was repeated at 25 saturation frequency offsets from ω = -6 to +6 ppm with a step of 0.5 ppm as well as one scan acquired far off-resonance (-1560 ppm) for signal normalization. For the APT imaging, the asymmetry analysis at 3.5 ppm downfield from the water signal was calculated. The mean APT signal intensity (SI) was compared between the benign and malignant tumors. RESULTS: The mean APT SI was 2.23 ± 0.80 % in the benign tumors and significantly higher at 2.99 ± 0.99 % in the malignant tumors (P = 0.01). A receiver operating curve analysis revealed that the optimal APT SI threshold was 2.40 for distinguishing malignant tumors from benign tumors with an area under the curve of 0.74. The sensitivity, specificity, and accuracy were 83.3%, 61.3%, and 67.4%, respectively. CONCLUSION: The mean APT SI of the malignant parotid tumors was significantly higher than that of the benign parotid tumors.

Pleomorphic adenoma of the hard palate with calcifications: an unusual presentation / Adenoma pleomórfico del paladar duro con calcificaciones: una presentación inusual

Pleomorphic Adenoma (PA) is the most common benign salivary gland tumor. The most common sites for minor salivary gland from which PA arises are the palate followed by the lips and buccal mucosa. Calcifications are a common finding in major salivary glands with chronic inflammatory disorders. Major salivary gland tumors rarely show calcifications and it is less common to find them in minor salivary gland tumors. We report a case of pleomorphic adenoma of the hard palate in a 67-year-old female patient with intra-tumoral, irregular and scattered calcifications visible on computed tomography (CT). The treatment was complete surgical excision of the lesion. The diagnosis was confirmed with the histopathological study.

El adenoma pleomórfico (AP) es el tumor benigno de las glándulas salivales más común. Los sitios de mayor frecuencia donde surge el AP en glándulas salivales menores es el paladar seguido de los labios y la mucosa bucal. Las calcificaciones son un hallazgo común en las glándulas salivales mayores con trastornos inflamatorios crónicos, pero en el caso de tumores rara vez muestran calcificaciones y es menos común encontrarlos en tumores de las glándulas salivales menores. Presentamos un caso de adenoma pleomórfico del paladar duro en una paciente de 67 años con calcificaciones intratumorales, irregulares y dispersas visibles en la tomografía computarizada. El tratamiento fue la extirpación quirúrgica completa de la lesión. El diagnóstico se confirmó con el estudio histopatológico

[Role of overexpression of myeloid cell leukemia-1-long in prognosis of malignant pleomorphic adenoma].

Objective: To evaluate the clinicopathological significance of the expression of the two myeloid cell leukemia-1 isoforms, myeloid cell leukemia-1-long (Mcl-1L) and myeloid cell leukemia-1-short (Mcl-1S) in malignant pleomorphic adenoma (MPA). Methods: A total of 56 patients with MPA treated with surgery, the expression of Mcl-1L and Mcl-1S were detected by quantitative real-time PCR (qPCR) in mRNA level, and by Western blotting in protein level, respectively. The correlation between clinicopathological parameters (gender, age, site, habits, size, node, metastasis, recurrence) was done using the chi-square test. Kaplan-Merier curve was used to analyze the survival in all patients, Log Rank test was performed to observe the difference between groups. Cox's proportional hazard test was used to identify the factors that were independent predictors of survival. Results: qPCR showed overexpression of Mcl-1L in 66.1%MPA patients (37/56), with significant difference in terms of tumor site, significantly higher expression of Mcl-1L in MPA (parotid gland: 2.21±1.07, sublingual gland: 2.12±1.08, other sites: 1.83±0.81) than benign pleomorphic adenoma tissue (1.00±0.19) (P<0.01). Western blotting analysis showed significantly higher expression of Mcl-1L in MPA (parotid gland: 1.02±0.43, sublingual gland: 0.71±0.29, other sites: 0.70±0.30) than benign pleomorphic adenoma tissue (0.39±0.08) (P<0.01). In malignant pleomorphic adenoma patients, high Mcl-1L expression was significantly associated with node positivity (P=0.045), advanced tumor size (P=0.002). Kaplan-Meier survival line analysis indicated a significantly lower survival time in Mcl-1L higher-expression patients (24.79±9.71) than lower-expression patients (30.59±9.01) (P=0.017). Multivariate analysis indicated Mcl-1L to be an independent prognostic factor for MPA (P=0.002). Conclusions: The studies suggest that overexpression of Mcl-1L is associated with poor prognosis in MPA. Mcl-1L is an independent prognostic factor in malignant pleomorphic adenoma.

[Clinical features and pathological analysis of lacrimal gland occupying lesions in 91 cases].

Objective: To analyze the pathogenesis, histopathological classification and clinical features of lacrimal gland occupying lesions. Methods: This was a retrospective case series study. Clinical data of 91 patients (102 eyes) with lacrimal gland area occupying diseases who received ophthalmic surgery in the Second People's Hospital of Yunnan Province from January 2014 to November 2018 were retrospectively analyzed, including patients' age, reasons for treatment, gender, imageological examination data and pathological diagnosis results. All patients had more than one medical imaging examination results and histopathological diagnosis results. Results: Among 91 cases, 46 patients (50.5%) were male and 45 (49.5%) were female. The age distribution ranged from 1.1 years to 72 years old, with an average age of 43 years. All of benign tumors added up to 58 cases (63.7%). Pleomorphic adenoma (43 cases, 47.3%), dermoid cyst (6 cases, 6.6%), and inflammatory pseudotumor (6 cases, 6.6%) were the most common cases in the benign lacrimal gland occupying tumors. There were 33 cases (36.3%) of malignant tumors. Adenoid cystic carcinoma (15 cases, 16.5%), adenocarcinoma (6 cases, 6.6%) and lymphoma (5 cases, 5.5%) had the highest incidence among the malignant lacrimal gland occupying tumors. The most common reason for seeking medical treatment was exophthalmos (50 cases, 54.9%; 30 cases were pleomorphic adenoma). Brow arch mass (22 cases, 24.2%) and pain in and around the eye (9 cases, 9.9%; 5 cases were adenoid cystic carcinoma) were also major reasons. Conclusions: The most common benign lacrimal gland area occupying lesion in surgery patients of Yunnan is pleomorphic adenoma, which more occurred in patients with exophthalmos as the main symptoms. The most common malignant tumor in the lacrimal gland area is adenoid cystic carcinoma and the most common reason to seek medical advice was pain in and around the eye. (Chin J Ophthalmol, 2019, 55:842-846).

[Recurrent maxillary sinus pleomorphic gonadoma into myoepithelial carcinoma: a case report].

Summary A 44-year-old woman with left nasal obstruction and facial numbness for 4 months was admitted to hospital. The patient did not have amblyopia, vision loss, runny nose with blood, dizziness ,headache or other discomfort.In 1991 and 2001, the patient were pathologically diagnosed as pleomorphic adenomas.CT of nasal cavity and paranasal sinuses showed that in the left maxillary sinus there was an about 4.4 cm×4.5 cm×4.7 cm large mass soft tissue density, showing expansive growth protruding into the left orbital floor.MRI showed that the lumped short T1 signal was seen in the left maxillary sinus and the linear long T1 signal was seen in the left nasal cavity, and the liquid accumulation signal foci could be seen in the left maxillary sinus.Postoperative pathological findings: （left maxillary sinus mass） Combining morphology, immunohistochemical results and medical history, consistent with pleomorphic adenoma carcinogenesis （cancer in pleomorphic adenoma）, carcinogenesis type is myoepithelial carcinoma.

Parotid Lymphoepithelial Cyst in a HIV-Negative Individual: A Case Report.

Benign lymphoepithelial cysts of the parotid are common in retropositive patients, but extremely rare in HIV-negative individuals. We present a 28-year-old man who presented with a painless, gradually increasing swelling in the left parotid region and was clinically diagnosed to have a pleomorphic adenoma of the left parotid gland. Preoperative blood investigations revealed that the patient was seronegative. He underwent a left superficial parotidectomy and the histopathology report indicated a benign lymphoepithelial cyst. The rarity of this lesion in a seronegative patient is the main reason for reporting this case.

Carcinoma Ex Pleomorphic Adenoma Presented as a Gigantic Tumor: Treatment and Diagnostic Challenges.

Parotid gland surgery can be challenging due to intricate relationship between the gland and facial nerve. Besides complete removal of the lesion, the main focus of surgery is centered on the facial nerve. Surgery can be technically demanding especially when the tumor is large or involves the deep lobe. We report a patient with a 30-year history of gigantic parotid mass, which initial fine-needle aspiration cytology reported as pleomorphic adenoma. The tumor, weighing 1.3 kg, was successfully resected with facial nerve preservation. Histopathological examination of the excised mass confirmed as carcinoma ex pleomorphic adenoma (CaExPA) of adenocarcinoma, not otherwise specified type. We describe the specific surgical and reconstruction techniques for successful removal of large parotid tumors with facial nerve preservation. To our knowledge, this is the heaviest CaExPA of the parotid gland in South-East Asian region.

Oncogenic DNA viruses found in salivary gland tumors.

BACKGROUND: Previous investigations studying the association of DNA viruses with salivary gland tumors (SGTs) have led to conflicting results. The aim of this study was to determine the prevalence of different DNA viruses by using a highly sensitive assay in a multi-center series of over 100 fresh frozen salivary gland samples. METHODS: DNA was isolated from 84 SGTs (80 parotid tumors and 4 submandibular gland tumors) and 28 normal salivary tissue samples from 85 patients in Northeast Italy. Using a highly sensitive type-specific multiplex genotyping assay, we analyzed the samples for the presence of DNA from 62 different viruses including 47 papillomaviruses, 10 polyomaviruses, and 5 herpesviruses. RESULTS: We observed a high prevalence of beta human papillomavirus DNA in malignant tumors. In contrast, polyomavirus DNA was present in benign, malignant, and non-tumor control samples. Most striking was the significant distribution of herpesvirus DNA in the SGT samples, in particular the high prevalence of Epstein-Barr type 1 and type 2 DNA in Warthin's tumor samples. CONCLUSION: Our data provides evidence for the presence of DNA viruses in SGTs. Mechanistic studies are needed to further attribute tumor formation to these viruses.

[Use of transmandibular approach for resection of a relapse pleomorphic adenoma on the parapharyngeal space]. / Abordaje transmandibular para resección de adenoma pleomorfo recidivante del espacio parafaríngeo.

In this review of a clinical case we study the most frequent benign neoplasia of the main salivary glands. We present the case of a four-year relapse of a patient post-operated of a conservative total parotidectomy. We expose different opinions about this neoplasia, and the clinical case of a 50-year old female patient that presents a relapse to the parapharyngeal space, for which we used a trans-mandibular approach.

En esta revisión de un caso clínico se estudia la neoplasia benigna más frecuente de glándulas salivales mayores. Se presenta el caso de una recidiva a cuatro años de una paciente postoperada de parotidectomía total conservadora. Se exponen diferentes opiniones sobre esta neoplasia y el caso clínico de una paciente de 50 años de edad, la cual presenta recidiva hacia el espacio parafaríngeo, para el que se realizó un abordaje transmandibular.

Giant Parapharyngeal Space Pleomorphic Adenoma Causing Acute Airway Obstruction.

Primary parapharyngeal space (PPS) tumors are rare, representing only 0.5% of all head and neck neoplasms. About 80% of tumors of this space are benign, and 20% are malignant. They often pose therapeutic and diagnostic problems due to variable non-specific symptoms and the complex anatomy of this space. Pleomorphic adenoma is the most common benign tumor of this space. It presents as an asymptomatic mass causing mild bulging in the soft palate or tonsillar region, or fullness near the angle of the mandible in the neck. We report the case of a 60-year-old male admitted to the emergency department with breathing difficulty and acute stridor. He was unable to maintain oxygen saturation, and an emergency tracheostomy was performed. Radiological and cytological evaluation were performed, and the patient was diagnosed as having primary PPS pleomorphic adenoma. The tumor was excised via the transcervical approach. The rarity of tumor in this space and unusual life-threatening presentation prompted the authors to report this case. To our knowledge, this is the third case reported worldwide of a pleomorphic adenoma causing upper airway obstruction and acute respiratory failure.