Current thinking about the management of recurrent pleomorphic adenoma of the parotid: a structured review

Machine learning-assisted diagnosis of parotid tumor by using contrast-enhanced CT imaging features

PURPOSE

This study aims to develop a machine learning diagnostic model for parotid gland tumors based on preoperative contrast-enhanced CT imaging features to assist in clinical decision-making.

MATERIALS AND METHODS

Clinical data and contrast-enhanced CT images of 144 patients with parotid gland tumors from the Peking University School of Stomatology Hospital, collected from January 2019 to December 2022, were gathered. The 3D slicer software was utilized to accurately annotate the tumor regions, followed by exploring the correlation between multiple preoperative contrast-enhanced CT imaging features and the benign or malignant nature of the tumor, as well as the type of benign tumor. A prediction model was constructed using the k-nearest neighbors (KNN) algorithm.

RESULTS

Through feature selection, four key features-morphology, adjacent structure invasion, boundary, and suspicious cervical lymph node metastasis-were identified as crucial in preoperative discrimination between benign and malignant tumors. The KNN prediction model achieved an accuracy rate of 94.44 %. Additionally, six features including arterial phase CT value, age, delayed phase CT value, pre-contrast CT value, venous phase CT value, and gender, were also significant in the classification of benign tumors, with a KNN prediction model accuracy of 95.24 %.

CONCLUSION

The machine learning model based on preoperative contrast-enhanced CT imaging features can effectively discriminate between benign and malignant parotid gland tumors and classify benign tumors, providing valuable reference information for clinicians.

Predictive value of neutrophil to lymphocyte ratio, platelet to lymphocyte ratio, and systemic inflammatory index for detection of recurrence of pleomorphic adenoma of the major salivary glands: a multicenter study

OBJECTIVE

The aim of this study was to investigate the correlation among inflammatory biomarkers, such as the systemic immune-inflammation index (SII), the neutrophil-to-lymphocyte ratio (NLR) and the platelet-to-lymphocyte ratio (PLR), and the recurrence of pleomorphic adenomas (PAs).

STUDY DESIGN

This was a retrospective multicenter study. Six hundred eight patients diagnosed with PA and treated by tumor enucleation were included in the analyses. The patients were extracted from a 20-year database of 2 referral centers (January 2000 to January 2020). Data about age, gender, voluntary habits, tumor characteristics, tumor treatment, and values of NLR, PLR, and SII were collected. A receiver operating characteristic (ROC) curve was used to calculate the optimal cutoff values for SII, PLR, and NLR. A linear regression model (LRM) and a nonlinear logistic regression model (NLRM) were implemented for NLR, PLR, and SII.

RESULTS

All 3 inflammatory parameters were statistically significant correlated to the recurrence of the tumor. The best performance was achieved by NLR (cutoff of 2.960) with area under the ROC curve (AUC) = 0.91, accuracy of 96.1%, sensitivity of 78.4% and specificity of 97.2%, PPV = 64.4%, and NPV = 98.6%. LRM and NLRM including all hematological parameters did not improve performance in terms of recurrence detection.

CONCLUSIONS

The use of 3 inflammatory biomarkers could be a useful tool to predict recurrence of tumor in case of PA ≤ 3 cm. NLR in particular could be sensitive with a cutoff of 2.960. The use of NLR, PLR, and SII could be a good reference point for surgical decision making and follow-up in clinical practice. (Oral Surg Oral Med Oral Pathol Oral Radiol YEAR;VOL:page range).

Recurrent pleomorphic adenoma: Epidemiology and surgical challenges; a single tertiary center experience

INTRODUCTION

Despite being less common in recent years, recurrent pleomorphic adenoma still poses a surgical challenge, especially after improper surgery.

METHODS

We retrospectively recruited all patients with recurrent pleomorphic adenoma and Carcinoma ex pleomorphic adenoma from February 2007 to April 2024 who were operated upon in a tertiary cancer center. Epidemiological, radiological, and pathological data, risk factors, details of surgical treatment, and surgical/oncological outcomes were analyzed.

RESULTS

35 patients with recurrent pleomorphic adenoma were recruited, 19 were women (54.3 %) with the parotid gland being the most affected site in 74.3 % followed by the submandibular gland in 20 %. Only 11 patients (31.4 %) underwent surgery for the primary tumor in our center, and of interest that 48.6 % of the total cohort underwent simple enucleation for their primary tumors. The interval between resection and recurrence was shortened with frequent recurrences. Again, 71.4 % of facial nerve injuries had a history of simple enucleation for their primaries. 3 cases of Carcinoma ex pleomorphic adenoma were reported, representing 1.4 % of the patients with parotid pleomorphic adenoma in the study period, and was associated with young age and long-standing recurrence.

CONCLUSIONS

Surgery is the cornerstone treatment for both primary and recurrent pleomorphic adenoma. Inadequate primary surgery, long-standing lesions, multiplicity, and fragmentation may be associated with facial nerve injury. Reconstructive flaps may be needed to cover the large resultant defects. Surgery for pleomorphic adenoma should be done by adequately trained surgeons. Radiation as an adjuvant treatment needs to be used frequently, especially through a multidisciplinary approach. Carcinoma ex pleomorphic adenoma, being rare, is demanding in its management with a poor prognosis.

Revision parotidectomy - analysis of indications for the procedure and treatment results based on 10 years of follow-up in a single center

<b>Introduction:</b> Surgical removal of recurrent parotid gland tumours is the first-line treatment but presents an increased risk of facial nerve injury and a considerable re-recurrence failure rate.<b>Aim:</b> Identification of individuals exposed to a higher risk of re-procedure, raising awareness in the preoperative setting, and proposing an optimal follow-up.<b>Methods:</b> The retrospective review included 72 patients treated with revision surgery in a single centre. The demographics, clinicopathologic variables, and operative details were analysed.<b>Results:</b> Recurrent pleomorphic adenoma (PA) was the main reason for reoperation (66.7%), followed by new monomorphic adenoma (13.9%), resection extension (12.5%), and malignancy recurrence (6.9%). Time to revision surgery was on average 68.6 months and was the shortest for extended resection cases (average 1.9 months). The period was substantially longer in recurrent PA (90.8 months). The final facial nerve function according to the House-Brackmann scale (HBS) decreased in 37% of patients after reoperation. The number of recurrences per patient ranged from one in 61% of cases to eight in a solitary case.<b>Conclusions:</b> The rate of revision parotid surgery was 8.4%. Negative margins at the first resection were not of protective significance. Recurrent PA was the main cause of revision surgery and over one-third of this cohort had a subsequent relapse. As many as 37% of patients experienced a decrease in facial nerve function following revision surgery.

"Unraveling the Tapestry": A Retrospective Exploration of Recurrent Parotid Pleomorphic Adenoma Cases

The standard surgical procedure for treating the parotid gland's recurrent pleomorphic adenoma (RPA) is parotidectomy with facial nerve preservation (FN). Treatment of RPA remains challenging since controversies occur regarding recurrence, degree of revision surgery, postoperative radiation, and difficulty in conserving the FN. A retrospective review of patient's medical records treated for benign parotid neoplasms was conducted between 2017 and 2022 to identify individuals who underwent surgery for RPA. Demographic information, surgical intervention details, pre-and postoperative facial nerve function, histopathological analysis, and recurrence rates were collected. These variables were compared in patients with single recurrent tumors versus patients with multiple recurrent tumors. Twenty-one patients met the criteria, including 13 with a first recurrence, 7 with a second recurrence, and 1 with a third recurrence. Following surgery for multiple RPA, long-term FN outcomes were significantly worse (P = 0.005). There were no observable risk factors for tumor recurrence. The interval between the initial revision surgery and subsequent ones was drastically shortened. Our study suggests that the risk of permanent facial paralysis is greater with subsequent surgical procedures. Early detection of recurrence can aid in early re-operation.

Utility of fine-needle aspiration biopsy (FNAB) in parotid pleomorphic adenoma diagnosis and management

PURPOSE

Pleomorphic adenoma (PA), the most common benign tumour of the parotid gland, requires accurate preoperative diagnosis owing to its capacity for malignant transformation. The aim of this study was to evaluate our experience with ultrasound-guided fine-needle aspiration biopsy (FNAB) in the diagnostic algorithm for patients with PA and to assess clinical outcomes for those with different surgical approaches.

MATERIAL AND METHODS

We carried out a retrospective analysis of patients treated for parotid gland mass between 2010 and 2016. These had had preoperative FNAB and had undergone subsequent surgery.

RESULTS

165 patients had FNAB with the result of PA and the definitive histology confirmed PA in 159 cases (96.4%). On the other hand, in 179 patients, the definitive histology showed PA and the preoperative FNAB result corresponded in 159 cases (88.9%). The measured sensitivity, specificity and accuracy of ultrasound-guided FNAB in the diagnosis of PA were, respectively, 88.83%, 96.23% and 92.31%. Most of the patients underwent superficial or partial superficial parotidectomy, followed by extracapsular dissection which was associated with statistically lower risk of facial nerve injury (P=0.04).

CONCLUSION

Ultrasound-guided FNAB is simple, accurate and valuable in the diagnosis of PA and provides results that can lead to the choice of less invasive operative treatment.

Deep learning based ultrasound analysis facilitates precise distinction between parotid pleomorphic adenoma and Warthin tumor

Background

Pleomorphic adenoma (PA), often with the benign-like imaging appearances similar to Warthin tumor (WT), however, is a potentially malignant tumor with a high recurrence rate. It is worse that pathological fine-needle aspiration cytology (FNAC) is difficult to distinguish PA and WT for inexperienced pathologists. This study employed deep learning (DL) technology, which effectively utilized ultrasound images, to provide a reliable approach for discriminating PA from WT.

Methods

488 surgically confirmed patients, including 266 with PA and 222 with WT, were enrolled in this study. Two experienced ultrasound physicians independently evaluated all images to differentiate between PA and WT. The diagnostic performance of preoperative FNAC was also evaluated. During the DL study, all ultrasound images were randomly divided into training (70%), validation (20%), and test (10%) sets. Furthermore, ultrasound images that could not be diagnosed by FNAC were also randomly allocated to training (60%), validation (20%), and test (20%) sets. Five DL models were developed to classify ultrasound images as PA or WT. The robustness of these models was assessed using five-fold cross-validation. The Gradient-weighted Class Activation Mapping (Grad-CAM) technique was employed to visualize the region of interest in the DL models.

Results

In Grad-CAM analysis, the DL models accurately identified the mass as the region of interest. The area under the receiver operating characteristic curve (AUROC) of the two ultrasound physicians were 0.351 and 0.598, and FNAC achieved an AUROC of only 0.721. Meanwhile, for DL models, the AUROC value for discriminating between PA and WT in the test set was from 0.828 to 0.908. ResNet50 demonstrated the optimal performance with an AUROC of 0.908, an accuracy of 0.833, a sensitivity of 0.736, and a specificity of 0.904. In the test set of cases that FNAC failed to provide a diagnosis, DenseNet121 demonstrated the optimal performance with an AUROC of 0.897, an accuracy of 0.806, a sensitivity of 0.789, and a specificity of 0.824.

Conclusion

For the discrimination of PA and WT, DL models are superior to ultrasound and FNAC, thereby facilitating surgeons in making informed decisions regarding the most appropriate surgical approach.

Parotid gland pleomorphic adenoma re-operations with regard to patient and surgeon satisfaction: what can be improved?

BACKGROUND

Surgery, the treatment of choice for parotid pleomorphic adenoma (PA), is associated with facial nerve palsy and decreased quality of life. Re-operation for PA recurrence (rPA) significantly increases these risks and constitutes a dilemma for both patient and surgeon. Factors influencing the success of re-operation, as well as the self-reported satisfaction of both sides, have yet to be addressed in the literature. This study aims to improve upon the decision-making schedule in PA re-operations, based on patient expectations, imaging, and concordance with the first operative report (FOpR).

METHODS

Seventy-two rPAs treated in a single tertiary center were collected and analyzed. The FOpRs and pre-operative imaging were divided according to defined criteria into accurate and non-accurate categories. The re-operative field and course were categorized as anticipated or unanticipated. The re-operation was categorized as satisfactory or unsatisfactory for both the patient and the surgeon.

RESULTS

The accuracy of FOpRs and pre-operative imaging was 36.1% and 69.4%, respectively. Re-operative courses were: 36.1% anticipated and 63.9% unanticipated. The most frequently omitted data were: presence of satellite tumors (9.7%), and amount of removed parenchyma (9.7%). Variables that most commonly affected FOpR non-accuracy were: tumor size (Chi2(1)=59.92; p < 0.001) and capsule condition (Chi2(1)=29.11; p < 0.001). There was no significant relationship between FOpR accuracy and re-operative course (Chi2(1)=1.14; p = 0.286), patient satisfaction (Chi2(1)=1.94; p = 0.164) or surgeon satisfaction (Chi2(1)=0.04; p = 0.837). Pre-operative imaging (Chi2(1)=36.73; p < 0.001) had the greatest impact on surgeon satisfaction.

CONCLUSION

Accurate pre-operative imaging impacted surgeon satisfaction. The impact of the FOpR on re-operation technicalities and patient satisfaction was minor. Imaging precision should be improved to streamline the decision-making process of PA re-operation. This article proposes suggestions for a future decision-making algorithm as a starting point for a prospective study.Key messagesAccurate pre-operative imaging impacts both surgeon and patient satisfaction.There is no significant relationship between the accuracy of the first operative report and surgeon and patient satisfaction.There is a statistically significant relationship between patient and surgeon satisfaction.

Reconstruction with facial artery musculo-mucosal flap (FAMM.F) after resection of upper lip pleomorphic adenoma: Case report

INTRODUCTION

Although pleomorphic adenoma (PA) is the most common neoplasm of both minor and major salivary glands, its presence in the buccal surface of upper lip is rare.

PRESENTATION OF CASE

A 70-year-old male presented with a chief complaint of recent rapid growth of a mass in the buccal aspect of the upper lip. A well-circumscribed mass measuring 3 × 2 cm with intact overlying mucosa without regional lymphadenopathy was evident. Core needle biopsy report was suggestive of PA. Complete excision of the tumor was performed. The defect was large and primary closure was not possible. Reconstruction with FAMM flap was planned. After 4 weeks, the flap was covered with epithelia and created a satisfactory result.

DISCUSSION

The definite diagnosis of PA is based on histopathological examination. The following features help to differentiate PA from other tumors; tubuloalveolar and gland-like structures, islands of cuboidal or polygonal cells in a chondroid, hyalinized, fibroadipose or mucinous hypocellular stroma which are stained positively for periodic acid-Schiff and Alcian. Despite these characteristics, differentiation of PA from dermal mixed tumor may be challenging especially when the specimen is from the upper lip. The main advantages of FAMM.F are being thin and pliable flap, having wide arc of rotation; being suitable for reconstruction of mucosal defects; resistance against postoperative radiotherapy and easy harvesting.

CONCLUSION

The FAMM flap is a reliable reconstruction technique for medium-sized intraoral defects with limited morbidity to the donor site. It provides functional reconstruction of the oral cavity with a low risk of post-operative complications.

An anatomy-aware framework for automatic segmentation of parotid tumor from multimodal MRI

Magnetic Resonance Imaging (MRI) plays an important role in diagnosing the parotid tumor, where accurate segmentation of tumors is highly desired for determining appropriate treatment plans and avoiding unnecessary surgery. However, the task remains nontrivial and challenging due to ambiguous boundaries and various sizes of the tumor, as well as the presence of a large number of anatomical structures around the parotid gland that are similar to the tumor. To overcome these problems, we propose a novel anatomy-aware framework for automatic segmentation of parotid tumors from multimodal MRI. First, a Transformer-based multimodal fusion network PT-Net is proposed in this paper. The encoder of PT-Net extracts and fuses contextual information from three modalities of MRI from coarse to fine, to obtain cross-modality and multi-scale tumor information. The decoder stacks the feature maps of different modalities and calibrates the multimodal information using the channel attention mechanism. Second, considering that the segmentation model is prone to be disturbed by similar anatomical structures and make wrong predictions, we design anatomy-aware loss. By calculating the distance between the activation regions of the prediction segmentation and the ground truth, our loss function forces the model to distinguish similar anatomical structures with the tumor and make correct predictions. Extensive experiments with MRI scans of the parotid tumor showed that our PT-Net achieved higher segmentation accuracy than existing networks. The anatomy-aware loss outperformed state-of-the-art loss functions for parotid tumor segmentation. Our framework can potentially improve the quality of preoperative diagnosis and surgery planning of parotid tumors.

Clinical parameters predictors of malignant transformation of recurrent parotid pleomorphic adenoma

Malignant transformation (MT) in recurrent parotid pleomorphic adenomas (PAs) is rare; therefore its occurrence lacks reliable predictive factors. Our goal was to clarify the predictors for MT of recurrent parotid PAs based on preoperative clinical parameters. Patients with a clinical diagnosis of recurrent parotid PA were retrospectively enrolled. The association between clinicopathologic variables and MT of PA was assessed using univariate and multivariate analyses. MT occurred in 11.8% of the 467 patients. In univariate analysis, three or more previous recurrences, newly developed facial nerve paralysis, difficulty in mouth opening, tumors with the largest tumor diameter ≥ 2.4 cm, and abnormal neck lymph node enlargement were associated with MT occurrence. Further, multivariate analysis showed that three or more previous recurrences, newly developed facial nerve paralysis, difficulty in mouth opening, and abnormal neck lymph node enlargement were independently related to MT. MT of recurrent PA was not uncommon. Clinical signs of malignancy included newly developed facial nerve paralysis, difficulty in mouth opening, three or more previous recurrences, and abnormal neck lymph node enlargement.

Clinico-histopathological review of 255 patients who underwent parotidectomy for pleomorphic adenoma: a 10-year retrospective study-a proposal for an optimal diagnostic and therapeutic algorithm for patients with recurrent pleomorphic adenoma

PURPOSE

Pleomorphic adenoma (mixed tumor) is the most common neoplasm of the parotid gland and one of the most frequent types of salivary gland tumor, generally with benign behavior and relatively slow growing. The adenomas could arise from the superficial, deep or from both superficial and deep parotid's lobes.

METHODS

The aim of this review is to retrospectively analyze the surgical management of patients with pleomorphic adenoma of the parotid gland performed at the Department of Otorhinolaryngology (Department of Sense Organs of "Azienda Policlinico Umberto I" in Rome), from 2010 to 2020, with a focus on the percentage of recurrence and on the complication related to surgery to suggest an optimal diagnostic and therapeutic algorithm for patients with recurrent pleomorphic adenoma. The analysis of the complications observed in case of different surgical approaches was performed using the X² test.

RESULTS

The choice of a surgical approach (superficial parotidectomy-SP, total parotidectomy-TP, extracapsular dissection-ECD) depends on several elements, such as the location and the size of the adenoma, the availability of existing technical facilities and the professional experience of the surgeon. A transient facial palsy was present in 37.6%, 2.7% reported a permanent facial nerve palsy, 1.6% developed a salivary fistula, 1.6% a post-operative bleeding and 2.3% showed Frey Syndrome.

CONCLUSION

The surgical management of this benign lesion is required, even in asymptomatic cases, to prevent the progressive growing and to reduce the risk of malignant transformation. The goal of surgical excision is to obtain the complete resection to minimize the risk of tumor recurrence and avoiding facial nerve disability. Therefore, an accurate preoperative study of the lesion and the choice of the most appropriate surgical treatment are essential to minimize the rate of recurrence.

Recurrent pleomorphic adenoma of the parotid gland: A population-based study with emphasis on re-recurrence and malignant transformation

BACKGROUND

This study aimed to analyze the prognostic determinants for re-recurrence and malignant transformation of parotid recurrent pleomorphic adenoma (RPA).

METHODS

Between January 2011 and December 2020, all the cases of RPA of the parotid gland at our single institution were reviewed.

RESULTS

A total of 168 patients were included in this study, with a median age of 41.5 years, and 20 (11.9%) patients developed re-recurrence during follow-up. It has been evidenced that recurrence times (single or multiple) was an independent prognostic factor for recurrence-free survival (p = 0.0264). A total of 26 (15.48%) patients experienced malignant transformation of parotid RPA, and older age (>45 year old), male sex, and higher clinical tumor staging (T3-T4) were significantly associated with malignant transformation of parotid RPA.

CONCLUSIONS

Recurrence times was an independent prognostic factor for re-recurrence of parotid RPA, and older male with high T-stage may more easily develop malignant transformation.

Histopathological Aspects of the Prognostic Factors for Salivary Gland Cancers

Salivary gland cancers (SGCs) are diagnosed using histopathological examination, which significantly contributes to their progression, including lymph node/distant metastasis or local recurrence. In the current World Health Organization (WHO) Classification of Head and Neck Tumors: Salivary Glands (5th edition), malignant and benign epithelial tumors are classified into 21 and 15 tumor types, respectively. All malignant tumors have the potential for lymph node/distant metastasis or local recurrence. In particular, mucoepidermoid carcinoma (MEC), adenoid cystic carcinoma (AdCC), salivary duct carcinoma, salivary carcinoma, not otherwise specified (NOS, formerly known as adenocarcinoma, NOS), myoepithelial carcinoma, epithelial-myoepithelial carcinoma, and carcinoma ex pleomorphic adenoma (PA) are relatively prevalent. High-grade transformation is an important aspect of tumor progression in SGCs. MEC, AdCC, salivary carcinoma, and NOS have a distinct grading system; however, a universal histological grading system for SGCs has not yet been recommended. Conversely, PA is considered benign; nonetheless, it should be cautiously treated to avoid the development of metastasizing/recurrent PA. The aim of this review is to describe the current histopathological aspects of the prognostic factors for SGCs and discuss the genes or molecules used as diagnostic tools that might have treatment target potential in the future.

Clinical outcomes and cost-effectiveness of superficial parotidectomy versus extracapsular dissection of the parotid gland: a single-centre retrospective study of 161 patients

Improvements in preoperative diagnostics and intraoperative techniques have made the surgical excision of benign parotid gland tumours less invasive. Extracapsular dissection (ECD) has become more popular in comparison to superficial parotidectomy (SP), the gold standard. Although clinical outcomes have been reported, reports on cost-effectiveness are limited. The aim of this retrospective study was to analyse the surgical outcomes and cost-effectiveness of ECD versus SP in benign parotid tumour surgery. A retrospective cohort of 161 patients treated between 2012 and 2020 was collected. Data concerning demographics, clinical outcomes, and cost-efficiency were recorded. Analysis of the 161 unilateral parotidectomy cases (59 SP, 102 ECD) showed a significantly longer operation time, anaesthesia time, and length of stay for SP patients (all P < 0.001). Regarding postoperative complications, transient facial nerve weakness (P < 0.001) and haematoma formation (P = 0.016) were more prevalent in the SP patients. The frequency of positive margins was lower for SP (P = 0.037). No case of recurrence was identified with either technique. ECD showed excellent clinical outcomes as well as a reduction in complications when compared to SP. ECD is a viable alternative for superficial benign parotid gland tumours after thorough preoperative clinical, pathological, and radiological examination. The reduction in operation, anaesthesia, and hospitalization times with ECD is likely to result in a gain in cost-effectiveness.

Superficial versus total parotidectomy for recurrent pleomorphic adenoma in the parotid gland

Recurrent pleomorphic adenoma (RPA) is a challenging disease because of difficulty in reoperation, a high rate of postoperative facial palsy, and potential malignant transformation. The optimal management of RPA is still arguable regarding the surgical extent and the necessity of radiotherapy. Therefore, this study compared the complication and re-recurrence rates of superficial versus total parotidectomy in a prospective cohort of 29 patients with RPA. Two surgical techniques were allocated to consecutive patients without randomization and blinding processes. Total parotidectomy was applied to lesions in deep or both lobes. Most early and late complication rates were statistically comparable between the two groups (P > 0.05). Transient and permanent facial nerve paralysis frequently occurred in 55 % and 14 % of all cases, respectively, without statistical difference between the two groups (P > 0.5). Only one patient (3 %) had re-recurrence after superficial parotidectomy during the mean follow-up of 89 months. Superficial or total parotidectomy is recommended to reduce the risk of further recurrence in patients with RPA.

Novel Technique for the Surgical Management of Pleomorphic Adenoma of the Upper Lip

Pleomorphic adenoma (PA) is one of the most common benign lesions of the salivary glands, with a majority of them occurring in the parotid gland. PA has origin from the epithelial and mesenchymal elements and can arise from both major and minor salivary glands. Among minor salivary glands, the palate is the most commonly affected site, followed by lips, cheeks, gingiva, the floor of the mouth, and tongue. PA of the upper lip without intraoral mucosal involvement is a rare entity. In this article, we report a case of PA of the upper lip in a middle-aged female patient and its surgical management with a novel technique. During six months’ postoperative review, the patient showed excellent wound healing with very minimal scar formation.

Pattern of facial nerve palsy during parotidectomy: a single-center experience

OBJECTIVE

This study was performed to report and analyze the prevalence of permanent facial nerve paralysis following parotidectomy for various benign and malignant lesions in a single center.

METHODS

This single-center retrospective study included all patients who underwent parotidectomy (total and superficial) for benign and malignant tumors and chronic inflammatory diseases during a 6-year period. Patients who had previously undergone an operation of the parotid gland and those with preoperative facial weakness were excluded.

RESULTS

The study included 127 patients ranging in age from 14 to 83 years (median, 45.89 years). Most patients were female (n = 83, 65.4%). The most prevalent procedure was superficial parotidectomy (n = 117, 92.1%), followed by total parotidectomy (n = 6, 4.7%). The average operative duration was 138 minutes (range, 80-400 minutes). Histopathology revealed that 109 (85.8%) patients had benign tumors, 14 (11.0%) had malignant tumors, and 4 (3.1%) had chronic sialadenitis. Only two patients sustained an injury to the cervical branch of the facial nerve.

CONCLUSION

In this single-center experience of parotid surgery, the rates of transient and permanent facial paralysis were acceptably low at 9.0% and 1.6%, respectively, for all pathologies.

Multifocal recurrence of pleomorphic adenoma of the lacrimal gland

Purpose

To report two cases of multifocal recurrent pleomorphic adenoma of the lacrimal gland, and to highlight the clinical and magnetic resonance imaging findings.

Observations

The authors present two patients with recurrent pleomorphic adenoma of the lacrimal gland. During their previous primary surgical resection at outside institutions, one patient reportedly had a macroscopically complete excision, while the second patient had violation of the pseudocapsule. Both patients had multiple recurrent nodular lesions detected on magnetic resonance imaging with extension beyond the surgical field of the primary resection. Both underwent subsequent lateral orbitotomy with resection of all identifiable nodules and histopathology was consistent with pleomorphic adenoma. In one patient, two nodules were found two months after the surgery, which grew slowly over the last four years. The second patient had no clinical or radiologic sign of recurrence at last follow up, three years after resection of multinodular recurrence.

Conclusions and importance

The two cases demonstrate the challenges in the management of multifocal recurrence of lacrimal gland pleomorphic adenoma. The multicentric nature of recurrent lesions in these two cases increase the risk of future recurrence, malignant transformation, and morbidity caused by surgery and radiation. Magnetic resonance imaging is the imaging study of choice, but it may still be inadequate in identifying all the nodules.

Radiomics and deep learning approach to the differential diagnosis of parotid gland tumors

PURPOSE OF REVIEW

Advances in computer technology and growing expectations from computer-aided systems have led to the evolution of artificial intelligence into subsets, such as deep learning and radiomics, and the use of these systems is revolutionizing modern radiological diagnosis. In this review, artificial intelligence applications developed with radiomics and deep learning methods in the differential diagnosis of parotid gland tumors (PGTs) will be overviewed.

RECENT FINDINGS

The development of artificial intelligence models has opened new scenarios owing to the possibility of assessing features of medical images that usually are not evaluated by physicians. Radiomics and deep learning models come to the forefront in computer-aided diagnosis of medical images, even though their applications in the differential diagnosis of PGTs have been limited because of the scarcity of data sets related to these rare neoplasms. Nevertheless, recent studies have shown that artificial intelligence tools can classify common PGTs with reasonable accuracy.

SUMMARY

All studies aimed at the differential diagnosis of benign vs. malignant PGTs or the identification of the commonest PGT subtypes were identified, and five studies were found that focused on deep learning-based differential diagnosis of PGTs. Data sets were created in three of these studies with MRI and in two with computed tomography (CT). Additional seven studies were related to radiomics. Of these, four were on MRI-based radiomics, two on CT-based radiomics, and one compared MRI and CT-based radiomics in the same patients.

Endoscopic-assisted resection of pleomorphic adenoma in the accessory parotid gland

Background : An accessory parotid gland (APG) is a common anatomical structure that occurs in 10%-56% of individuals. Pleomorphic adenomas are the most common benign tumors of the APG, and their ideal treatment is surgical excision, although there is a risk for aesthetic disorders and facial nerve damage due to the site of origin. Moreover, despite being benign, these tumors are known to recur. Therefore, it is necessary to achieve both reliable excision and avoidance of facial nerve damage. Case presentation : We report a case of a 49-year-old Japanese man with a mass in his left cheek. The lesion was diagnosed as a benign salivary gland tumor derived from the APG by computed tomography imaging, magnetic resonance imaging and fine needle aspiration cytology. We resected the tumor using modified high submandibular incision under the endoscopic-assisted field of view. Discussion and Conclusions : The tumor was less invasive and reliably resected using an endoscope. In surgical treatment, the endoscopic-assisted technique is very useful to achieve complete tumor resection and prevent relapse while avoiding serious complications due to surgical procedures. J. Med. Invest. 68 : 376-380, August, 2021.

Deep Learning for Differentiating Benign From Malignant Parotid Lesions on MR Images

Purpose/Objectives(s)

Salivary gland tumors are a rare, histologically heterogeneous group of tumors. The distinction between malignant and benign tumors of the parotid gland is clinically important. This study aims to develop and evaluate a deep-learning network for diagnosing parotid gland tumors via the deep learning of MR images.

Materials/Methods

Two hundred thirty-three patients with parotid gland tumors were enrolled in this study. Histology results were available for all tumors. All patients underwent MRI scans, including T1-weighted, CE-T1-weighted and T2-weighted imaging series. The parotid glands and tumors were segmented on all three MR image series by a radiologist with 10 years of clinical experience. A total of 3791 parotid gland region images were cropped from the MR images. A label (pleomorphic adenoma and Warthin tumor, malignant tumor or free of tumor), which was based on histology results, was assigned to each image. To train the deep-learning model, these data were randomly divided into a training dataset (90%, comprising 3035 MR images from 212 patients: 714 pleomorphic adenoma images, 558 Warthin tumor images, 861 malignant tumor images, and 902 images free of tumor) and a validation dataset (10%, comprising 275 images from 21 patients: 57 pleomorphic adenoma images, 36 Warthin tumor images, 93 malignant tumor images, and 89 images free of tumor). A modified ResNet model was developed to classify these images. The input images were resized to 224x224 pixels, including four channels (T1-weighted tumor images only, T2-weighted tumor images only, CE-T1-weighted tumor images only and parotid gland images). Random image flipping and contrast adjustment were used for data enhancement. The model was trained for 1200 epochs with a learning rate of 1e-6, and the Adam optimizer was implemented. It took approximately 2 hours to complete the whole training procedure. The whole program was developed with PyTorch (version 1.2).

Results

The model accuracy with the training dataset was 92.94% (95% CI [0.91, 0.93]). The micro-AUC was 0.98. The experimental results showed that the accuracy of the final algorithm in the diagnosis and staging of parotid cancer was 82.18% (95% CI [0.77, 0.86]). The micro-AUC was 0.93.

Conclusion

The proposed model may be used to assist clinicians in the diagnosis of parotid tumors. However, future larger-scale multicenter studies are required for full validation.

Observation Rather than Surgery for Benign Parotid Tumors: Why, When, and How

Surgery is the preferred treatment of benign parotid lesions, but it carries a risk of complications. Therefore, the approach toward the surgery of these lesions should seek to avoid complications. There are no guidelines or recommendations for when not to operate. Integration of comorbidities and other factors shift the scales from surgery toward observation in a small subset of patients presenting with parotid tumors. When observation is chosen, the patient should be followed frequently and cautiously, and the surgeon should be prepared to change strategy to surgical excision if in doubt.

Comparison of Parotidectomy With Observation for Treatment of Pleomorphic Adenoma in Adults

Importance

There is no consensus regarding optimal management of pleomorphic adenoma in adults.

Objectives

To compare parotidectomy with observation for the management of pleomorphic adenoma in patients 50 years or older by age.

Design and Setting

This decision analytical model was performed from November 21, 2019, to June 15, 2020, using a Markov model. Model variables and ranges were selected based on a literature review. A 1-way sensitivity analysis was performed to evaluate the age threshold at which each algorithm, either upfront elective parotidectomy or observation, would be favored. A Monte Carlo probabilistic sensitivity analysis using variable ranges was then performed 5 times with patients in the model assigned a starting age of 50, 60, 70, 80, and 90 years to assess how age at diagnosis would be associated with the model results.

Main Outcomes and Measures

Model outcomes were measured with quality-adjusted life-years (QALYs).

Results

In the study models, the age thresholds at which observation became more beneficial than parotidectomy were 88.5 years for patients with superficial lobe tumors (5.37 QALYs in favor of parotidectomy below this age, and 5.37 QALYs in favor of observation above this age) and 83.4 years for patients with deep lobe tumors (7.51 QALYs in favor of surgery below this age, and 7.51 QALYs in favor of observation above this age). There was no significant difference in outcomes between parotidectomy and observation among patients aged 70 to 80 years.

Conclusions and Relevance

This study suggests that the outcomes associated with parotidectomy and observation are similar at 70 years or older among patients with pleomorphic adenoma and that observation may be the favorable treatment in that age group.

Comprehensive characterization of pleomorphic adenoma at intraoral unusual sites

OBJECTIVE

The present study aimed to comprehensively characterize the epidemiologic characteristics, clinicopathologic characteristics, clinical treatments, and prognoses of pleomorphic adenoma (PA) identified at unusual intraoral sites.

STUDY DESIGN

Patients diagnosed with PA in oral and maxillofacial regions at our institution in the past 16 years (2005-2020) were screened from the inpatient disease registry. All data concerning patients with PA found at unusual intraoral sites (defined as intraoral locations except sublingual gland and palate) were retrieved. Previously published cases with adequate clinicopathologic data were collected from PubMed and Embase. Eligible cases were further reviewed and included for statistical analyses.

RESULTS

Among 1039 cases of PA diagnosed at our institution, 52 lesions were found at unusual intraoral sites. A literature review identified another 63 eligible cases from 32 articles. The upper lip was the most common sites for these lesions (n = 57), followed by buccal mucosa (n = 34), tongue (n = 8), lower lip (n = 8), and retromolar area (n = 2). Recurrence and malignant transformation after surgical resection were extremely rare for these lesions.

CONCLUSIONS

PA might rarely develop at uncommon intraoral sites with atypical presentations, thus complicating its early diagnosis. Surgical resection is the major therapeutic strategy for this rare entity and has a favorable prognosis.

Salivary Gland Pleomorphic Adenomas Presenting With Extremely Varied Clinical Courses. A Single Institution Case-Control Study

Objective

Pleomorphic adenomas (PAs) with divergent clinical behavior, differing from the vast majority of PAs, were distinguished. “Fast” PAs are characterized by an unexpectedly short medical history and relatively rapid growth. The reference group consisted of “slow” PAs with very stable biology and long-term progression. We divide the PA group as a whole into three subsets: “fast,” “normal,” and “slow” tumors. Our goal is a multifactorial analysis of the “fast” and “slow” PA subgroups.

Methods

Consecutive surgeries in a tertiary referral center, the Department of Otolaryngology and Laryngological Surgery, Poznan University of Medical Sciences, Poland, were carried out between 2002 and 2011. Out of 1,154 parotid tumors, 636 (55.1%) were PAs. The data were collected prospectively in collaboration with the Polish National Registry of Benign Salivary Gland Tumors. The main outcome measure was the recurrence rate in “fast” and “slow” PA subgroups. All surgical qualifications and surgeries were performed by two experienced surgeons.

Results

Slow PAs, compared to fast PAs, presented in older patients (53.25 ± 15.29 versus 47.92 ± 13.44 years). Multifactor logistic regression analysis with recurrence (yes/no) as the outcome variable, fast/slow as the predictor variable and age, gender, margin, FN status as covariates showed that fast PAs were significantly predicting recurrence vs. slow PAs (p = 0.035). Fast PAs were increasing the risk of PAs 10-fold vs. slow PAs, exp β = 10.20, CI₉₅ [1.66; 197.87]. The variables impacting relapse were recent accelerated growth of the tumor OR = 3.35 (SE = 0.56), p = 0.030, positive margins OR = 7.18 (SE = 0.57), p < 0.001, incomplete or bare capsule OR = 9.91 (SE = 0.53), p = 0.001 and location III OR = 3.12 (SE = 0.53), p = 0.033. In the multivariate model only positive margin was selected as the best predictor of relapse, OR = 5.01 (SE = 0.60), p = 0.007.

Conclusions

The simple clinical aspect of slow or fast PA progression is of great practical importance and can constitute a surrogate of the final histopathological information that is derived from the surgical specimen. The slow or fast nature of the PA to some extent indicates prognostic features such as recurrence risk. This finding requires correlation with histological and molecular features in further stages of research.

Long-term follow-up after extracapsular dissection of parotid pleomorphic adenomas - A retrospective study

Introduction:

Parotid pleomorphic adenoma (PPA) is the most common benign salivary gland neoplasm. Extracapsular dissection (ED) arose as a conservative surgical technique alternative to superficial parotidectomy to reduce complications.

Materials and Methods:

Patients who underwent ED for superficial, <3 cm, mobile parotid lumps (Quer I) between 2004 and 2008 were retrospectively analysed focusing on those with histological diagnosis of pleomorphic adenoma. A retrospective cohort study on 50 patients who accepted to undergo ultrasonography and clinical evaluation for at least 10 years since surgery was performed. Clinical data, surgical reports, and validated questionnaires for the assessment of complications, quality of life (QoL) and aesthetic satisfaction were analysed. Recurrence rate and complications after ED, with their QoL and aesthetic impact, were evaluated. Statistical analysis was performed setting α=0.05 as the level of significance.

Results:

Low occurrence of complications related to ED was seen. Overall QoL after ED was very good (range 1–7, mean 6,86), due to low complications incidence of complications and their low severity, as assessed by patients through Parotidectomy Outcome Inventory-8 questionnaire. Overall aesthetic satisfaction was high (range 1–10, mean 9,78). Aesthetic satisfaction and QoL was statistically related to onset of complications (P = 0.02504 and P = 0.001859). Tumour localization and dimension was not statistically related to onset of complications (P = 0.8207 and 0.7586). After a mean follow-up of 12.5 years, no recurrences were detected.

Discussion:

There is a lack of studies with a long-term follow-up after ED for the evaluation of recurrences and complications. Considering our results, the ED technique should be adopted as the first surgical approach for Quer I PPA without suspicion of malignancy.

Risk factors for subsequent recurrence after surgical treatment of recurrent pleomorphic adenoma of the parotid gland

BACKGROUND

Recurrent pleomorphic adenoma (PA) can be a lifelong disease, and rates of subsequent recurrence are high.

METHODS

Patients between 2000 and 2015 were identified. Primary outcome was subsequent recurrence after surgical salvage.

RESULTS

Twenty-seven of 84 patients developed a subsequent recurrence. Risk factors for subsequent recurrence included a higher number of previous recurrences (P < .01), worse preoperative facial nerve function (P < .01), and deep parotid lesion(s) (P < .01). Interval since last surgery was protective (P < .01), specifically >10 years since last surgery (P < .01). For patients with a >10-year interval since their last surgery, the subsequent recurrence-free rate at 10 years follow-up was 80.2% vs 31.8%.

CONCLUSIONS

For patients presenting with a >10-year interval since their last surgery, subsequent recurrence rates are low, which may allow for as needed surveillance recommendations. For patients presenting with recurrent PA and ≤10 years since their last surgery, a closer surveillance is warranted.

Recurrent pleomorphic adenoma of the parotid gland: A comparison of radiographic and pathologic tumor burden

PURPOSE

To compare recurrent pleomorphic adenoma tumor burden as detected on magnetic resonance and computerized tomography imaging with postoperative histopathology.

MATERIALS AND METHODS

44 patients were identified at a tertiary medical center between 2000 and 2015. Patients were included if they had viewable preoperative imaging and a postoperative diagnosis of recurrent pleomorphic adenoma. Primary outcomes were differences in the number and size of lesions detected on imaging and pathology.

RESULTS

The size in greatest dimension between pathology and imaging was not significant on aggregate MRI + CT (p = 0.78), MRI (p = 0.41), or CT (p = 0.69). There were more lesions found on pathology compared to both aggregate MRI + CT (p = 0.003) and CT alone (p = 0.014). The number of lesions between MRI and pathology failed to reach significance (p = 0.06). On univariate analysis, the interval between imaging and pathology (recurrent surgery) did not significantly affect the number of lesions detected (p = 0.18). On multivariable analysis, CT as the primary imaging modality and >1 recurrence was independently associated with greater inaccuracy with respect to number of lesions detected (p = 0.006; p = 0.008).

CONCLUSION

The size of the largest lesion on pathology can be accurately determined with imaging. Compared to MRI, CT scans significantly underpredict the number of lesions found on pathology. MRI should be prioritized unless contraindications exist. These findings will help guide imaging choice, preoperative planning, and patient counseling.

Risk factors for carcinoma ex pleomorphic adenoma in patients presenting with recurrence after resection of pleomorphic adenoma

BACKGROUND

In patients presenting with recurrent pleomorphic adenoma (rPA), clinical evaluation can fail to recognize carcinoma ex PA (cxPA). We aim to identify the risk factors for cxPA.

METHODS

This is a single institution retrospective case-control study from 2000 to 2015. CxPA was diagnosed based on surgical pathology. Demographics, clinical, and social histories were collected.

RESULTS

A number of 13/106 (12.3%) patients were diagnosed with cxPA, of which only 4/13 (31%) had clinical features suspicious for malignancy. Compared to benign rPA, factors associated with cxPA included age >50 (odds ratio [OR] 6.67, 95% confidence interval [CI]: 1.71-25.98, P < .01), >10 pack-years of smoking history (OR 3.36, 95% CI: 1.01-11.14, P = .04), and the largest tumor being >2 cm on pathology (OR 4.42, 95% CI: 1.14-17.10, P = .03).

CONCLUSIONS

In patients presenting with rPA, risk factors for malignant transformation include age >50, significant smoking history, and tumors larger than 2 cm. Clinical signs of malignancy such as rapid growth or pain are not always present.

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.

Guidelines of the French Society of Otorhinolaryngology-Head and Neck Surgery (SFORL), part II: Management of recurrent pleomorphic adenoma of the parotid gland

INTRODUCTION

The authors present the guidelines of the French Society of Otorhinolaryngology-Head and Neck Surgery (SFORL) for the management of recurrent pleomorphic adenoma (RPA) of the parotid gland.

METHOD

A review of the literature was performed by a multidisciplinary task force. Guidelines were drafted, based on the articles retrieved and the work group members' individual experience. There were then read and re-edited by an independent reading group. The proposed recommendations were graded A, B or C on decreasing levels of evidence.

RESULTS

Complete resection under neuromonitoring is recommended in case of RPA. The risks of progression and malignant transformation, which are higher the younger the patient, have to be taken into consideration. The risk of functional sequelae must be explained to the patient. MRI is recommended ahead of any surgery for parotid RPA, to determine extension and detect subclinical lesions. Radiotherapy should be considered in case of multi-recurrent pleomorphic adenoma after macroscopically complete revision surgery at high risk of new recurrence (microscopic residual disease), in case of RPA after incomplete resection, and in non-operable RPA.

Selection of the surgical approach for lesions with parapharyngeal space involvement: A single-center experience on 153 cases

BACKGROUND

The parapharyngeal space (PPS) can harbor a variety of tumors that can be approached through a wide spectrum of surgical routes. A decisional algorithm on the surgical approach to resect PPS lesions was tested in terms of reliability by retrospectively applying it to a large series of patients.

METHODS

Patients treated at the Unit of Otorhinolaryngology - Head and Neck Surgery of the University of Brescia, Italy, for tumor or tumor-like lesions involving the PPS between October 1986 and July 2019 were included in the retrospective analysis. Tumor characteristics, clinical presentation, diagnostic work-up, type of resection, surgical approach, and oncologic and morbidity outcomes were reviewed. Reliability of the algorithm was calculated as the number of cases in which the expected approach was confirmed/total number of cases × 100.

RESULTS

The analysis included 153 patients. Most lesions (64.1%) were benign. The most frequent complaint at presentation was unilateral oropharyngeal medialization (47.1%), followed by neck/parotid swelling (41.2%). Ninety-two (61.3%) lesions were excised through an enucleation/extracapsular dissection. Wide-margin resection and compartmental resection were performed in 17 (11.3%) and 41 (27.3%) patients, respectively. A single-corridor approach was employed in 132 (87.4%) cases. Combinations of multiple corridors were adopted in 19 (12.6%) patients. Reliability of the decision-making algorithm was 91.2%. Capsular integrity and margin status affected prognosis of pleomorphic adenomas and PPS malignancies, respectively.

CONCLUSION

The proposed decision-making algorithm can reliably guide approach selection, which should primarily aim at ensuring intact-capsule excision of benign lesions suspicious for pleomorphic adenomas and clear-margins resection of PPS malignancies.

An Improved and Simplified Approach to Identify the Facial Nerve During Parotid Surgery

Precise identification and preservation of the facial nerve is mandatory to avoid dysfunction of the facial nerve during parotidectomy. In this article, the authors are introducing a new landmark to identify the facial nerve for parotidectomy that is more protective for the facial nerve. The authors use a simple approach to predict the position of facial nerve main trunk intraoperatively without geometric calculations and a lot of landmarks. An imaginary almost 2 cm line is drawn between mastoid tip inferiorly and bony-cartilaginous junction of the external auditory canal superiorly. The main trunk of the facial nerve can be visualized at the midpoint of this line. The authors have been using this landmark successfully for the last 10 years, without any functional deficit of the parotid nerve. Identifying the facial nerve at the trunk level by this landmark renders following the branches forward in the glandular parenchyma less complicated.

Recent advances in the histopathological assessment of salivary disease

BACKGROUND

Salivary gland disease includes a wide range of unique and rare conditions that are treated by ear, nose and throat (ENT), oral and maxillofacial surgeons (OMFS) and oral medicine specialists. Histopathological diagnosis is pivotal to making a diagnosis and treatment planning. There is a vast range of conditions and controversies in the histopathological assessment of salivary gland diseases. Most colleagues in oral pathology and oral medicine work closely with the OMFS but might have missed some of the recent articles published by the speciality.

METHODS

We reviewed articles thought to be relevant to oral medicine and pathology specialists published over an 8-year period between 2012 and 2019 in the leading British Journal of Oral and Maxillofacial Surgery (BJOMS).

RESULTS

A total of 44 published articles relating to the histopathology of salivary glands disease were selected. Papers were published on population studies, benign and malignant tumours, sialadenitis, metastasis to the parotid gland and cytology. The publication type and numbers published were as follows: review (n = 9), meta-analysis/randomised controlled study (n = 1), retrospective study (n = 10) and case report/technical notes (n = 23).

CONCLUSIONS

The greatest proportion of publications published in BJOMS were case reports. This emphasises the paucity of consensus and the need for development in this field. Salivary gland disease remains an area with many controversies and would benefit from further research.

A new ligand of CD105 screened out by phage display technology provides a reliable identification of recurrent or metastasizing pleomorphic adenoma from pleomorphic adenoma

OBJECTIVES

To assess CD105 expression in pleomorphic adenoma (PA), recurrent pleomorphic adenoma (RPA) and metastasizing pleomorphic adenoma (MPA), to identify new epitopes and screen a ligand with high affinity to CD105 by phage display technology, to evaluate the reliability of the new ligand for identifying RPA/MPA from PA.

METHODS

Phage display technology was used to screen ligands with high affinity to recombinant human CD105. The ligand with strongest affinity to CD105 was synthesized by FMOC Chemistry according to the sequencing results. The archived formalin fixed paraffin-embedded (FFPE) tissues of 35 PA cases, 12 RPA cases and 2 MPA cases were sliced and immunofluorescent stained. CD105 expression were detected by Confocal laser scanning microscopy (CLSM). The relative fluorescence intensity was calculated with the image processing software Image J. Statistical analyses were performed by the software Graph Pad Prism (Version 7.0a). Using PROC logistic, receiver operating characteristic (ROC) curves, area under ROC curves (AUCs) were generated to assess the sensitivity and specificity of the new ligand for identifying RPA/MPA from PA cases.

RESULTS

A ligand with specialty and high affinity to CD105 i.e. ligand nABPK296 were developed. FITC-labeled ligand nABPK296 confirmed the difference of CD105 expression in RPA/MPA and PA. The AUC of nABPK296 was 0.9418.

CONCLUSIONS

CD105 is a promising biomarker for identification of RPA/MPA from PA cases. Ligand nABPK296 provides a promising approach to CD105 detection. This study also validated the reliability of phage display technology in finding new episodes and ligands with high affinity for antigens.