Pulmonary mucoepidermoid carcinoma: diagnosis and treatment

Rare but clinically important salivary gland-type tumor of the lung: A review

Salivary gland-type tumor (SGT) of the lung, which arises from the bronchial glands of the tracheobronchial tree, was first recognized in the 1950s. SGT represents less than 1% of all lung tumors and is generally reported to have a good prognosis. Mucoepidermoid carcinoma (MEC) and adenoid cystic carcinoma (ACC) are the two most common subtypes, comprising more than 90% of all SGTs. The reported 5-year survival rate of patients with SGT is 63.4%. Because this type of tumor develops in major bronchi, patients with SGT commonly present with symptoms of bronchial obstruction, including dyspnea, shortness of breath, wheezing, and coughing; thus, the tumor is usually identified at an early stage. Most patients are treated by lobectomy and pneumonectomy, but bronchoplasty or tracheoplasty is often needed to preserve respiratory function. Lymphadenectomy in the surgical resection of SGT is recommended, given that clinical benefit from lymphadenectomy has been reported in patients with MEC. For advanced tumors, appropriate therapy should be considered according to the subtype because of the varying clinicopathologic features. MEC, but not ACC, is less likely to be treated with radiation therapy because of its low response rate. Although previous researchers have learned much from studying SGT over the years, the diagnosis and treatment of SGT remains a complex and challenging problem for thoracic surgeons. In this article, we review the diagnosis, prognosis, and treatment (surgery, chemotherapy, and radiotherapy) of SGT, mainly focusing on MEC and ACC. We also summarize reports of adjuvant and definitive radiation therapy for ACC in the literature.

MAML2 gene rearrangement occurs in all Warthin-like mucoepidermoid carcinoma: A reappraisal in a series of 29 cases

Background

Warthin-like Mucoepidermoid carcinoma (MEC) is a new and rare morphological variant of MEC, with only a few case reports in the literature. The clinicopathological, molecular features and bio-behaviors of Warthin-like MEC has not been studied extensively. We reappraisal all Warthin-like MEC patients diagnosed and treated at our hospital.

Methods

Patient characteristics including clinicopathological features, genetic aberrations, treatment, and prognostic information were assessed and evaluated.

Results

Twenty-nine Warthin-like MEC patients were identified, 19 patients were female (65.5 %), and 10 were male (34.5 %). The patients' age varied widely from 8 to 68 years (mean 42.3 years). Genetic aberrations of MAML2 rearrangement were detected in all Warthin-like MEC patients, which suggesting this genetic event is the unique feature of Warthin-like MEC. Twenty-five patients (86.2 %) were assessed as having a low-stage disease (I/II), and four (13.8 %) as having high-clinical stage disease (III/IV). More than half of the patients (16/29) underwent only partial sialoadenectomy; 2 patients underwent extended sialoadenectomy, and 11 patients underwent extended sialoadenectomy with cervical lymph node dissection. After a median follow-up time of 73 months (5-128 months), Twenty-eight patients were alive without recurrence at the end of the follow-up period, one patient died 1 year after surgery due to lung metastasis.

Conclusion

Our data suggested that most Warthin-like MEC exhibited mild clinicopathological course and less aggressive bio-behavior, and an aggressive bio-behavior seemed to be very rare. In addition, in the salivary gland, MAML2 rearrangement seems to be a unique molecular feature of salivary Warthin-like MEC.

Pulmonary mucoepidermoid carcinoma in children: two case reports and a review of the literature

Pulmonary mucoepidermoid carcinoma (PMEC) is a rare tumor, particularly in children, and its clinical manifestations vary. When the tumor is small, it may be asymptomatic; however, with larger tumors, patients may present with symptoms such as recurring pneumonia, atelectasis, persistent cough, chest pain, and even hemoptysis. PMEC appears as an exophytic intrabronchial mass. This study aims to report on the clinical manifestations, imaging findings, treatment approaches, and prognosis of two children diagnosed with PMEC at our hospital between January 2018 and December 2022. The age of onset for both children was 9 years, and the masses were located in the right upper lobe bronchi. Following surgical treatment, both patients showed a good prognosis. In addition, we conducted a comprehensive review of the relevant literature to enhance the overall understanding of PMEC.

Mucoepidermoid Carcinoma of the Lung Harboring MET Exon 14 Skipping Mutation Treated With Tepotinib: A Case Report

A case of pulmonary mucoepidermoid cancer harboring MET exon 14 skipping mutation and responding to tepotinib.

Video-assisted Rigid Endoscopic Laser Ablation for Endobronchial Mucoepidermoid Carcinoma in Pediatrics Without Pulmonary Resections

INTRODUCTION

Mucoepidermoid carcinoma (MEC) is a rare malignancy of primary endobronchial lesions in children. Early diagnosis is crucial for the disease, but it is often misdiagnosed as asthma or lung infection. Chest computed tomography and bronchoscopy are the most important diagnostic tools. Surgical resection is the current treatment of choice for low-grade MEC. In the past, lobectomy, sleeve lobectomy, or segmental resections were the most standard surgeries. Endoscopic treatment was used for lung preservation and effectual removal of the lesions.

METHODS

A retrospective study of pediatric patients with primary endobronchial lesions who underwent rigid bronchoscopic laser ablation since 2010 was conducted. Pre-operative images, endoscopic pictures, post-operative images, histological analyses, and patients' clinical conditions were recorded and illustrated.

RESULTS

Four patients were enrolled. Three patients presented initially with cough or hemoptysis. The lesion sites were the bronchus of the left upper lobe, left lower lobe, left main bronchus, and trachea. All patients underwent bronchoscopic laser ablation for tumor excision without anatomical resection. No major surgical complications were encountered. All patients survived without recurrence after a mean postoperative follow-up of 4.5 years (3-6 years).

CONCLUSION

Video-assisted rigid endoscopic laser ablation for pediatric low-grade endobronchial MEC is a feasible, effective, and safe method. Close follow-up is essential for lung preservation management.

EVIDENCE LEVEL

Level IV.

TYPE OF STUDY

Case series with no comparison group.

Endoscopic resection of bronchial mucoepidermoid carcinoma in a young adult man: A case report and review of literature

BACKGROUND

Primary tracheobronchial mucoepidermoid carcinoma (MEC), derived from salivary mucus glands, is an uncommon neoplasm in adults. At present, surgery is still the preferred treatment for adult bronchial MEC, although it may cause significant trauma and loss of lung function. Here, we report a patient with endobronchial MEC who received the interventional bronchoscopic therapy to remove the neoplasm and no recurrence occurred during follow-up.

CASE SUMMARY

A 28-year-old man was admitted to our unit with mild hemoptysis for 3 d. Physical examination did not show any abnormal signs, and the serological indexes were all in the normal range. Chest computed tomography (CT) indicated an intraluminal nodule in the bronchus intermedius with homogeneous density and a well-defined margin. Upon fiberoptic bronchoscopy, an endobronchial pedunculated polypoid was discovered without submucosal involvement. As the neoplasm was confined to the bronchus, interventional bronchoscopy was performed to remove the mass by high-frequency electric knife and laser resection. Tissue was sampled and histopathological examination confirmed the diagnosis of low-grade MEC. As the proliferation index was low, no further treatment was given. During 2 years of follow-up, the patient’s condition was good and no relapse was discovered under fluorescence bronchoscopy or CT scan.

CONCLUSION

Interventional bronchoscopy can be considered for treatment of low-grade bronchial MEC, with few complications and preserved lung function.

Pulmonary Salivary Gland Tumor, Mucoepidermoid Carcinoma: A Literature Review

Pulmonary mucoepidermoid carcinoma (PMEC) is the most common malignant salivary gland tumor in the lungs and accounts for 0.1-0.2% of all lung malignancies in adults. It has no specific epidemiological or clinical characteristics. Correct diagnosis requires the combined examinations of images, laboratories, pathology, and immunohistochemistry (IHC) as well as molecular characteristics. PMEC tumors are characterized by squamous, intermediate, and mucus-secreting cells. Currently, histological appearance, mitotic frequency, cellular atypia, and necrocytosis allow the classification of PMEC into low grade or high grade. Molecular changes are crucial to pathological diagnosis. The driver of PMEC seems to be the fusion protein MECT1-MAML2 that is generated from a genetic mutation in t (11; 19) (q21; p13), while other gene mutations are also reported. However, no treatment of PMEC exists so far; surgical excision is still the primary treatment, while the efficacies of chemotherapy or radiotherapy are undefined. Tyrosine kinase inhibitor (TKI) therapy and immunotherapy showed to have significant therapeutic effects but require more investigation and better understanding. This review focuses on the clinical characteristics, imaging and pathologic features, immunohistochemical examination, mutation analysis, differential diagnosis, prognosis, and treatment of PMEC.

The Clinical and Prognostic Characteristics of Primary Salivary Gland-Type Carcinoma in the Lung: A Population-Based Study

This study aimed to explore the clinical and prognostic characteristics of primary salivary gland-type carcinoma (SGC). The entire cohort from the Surveillance, Epidemiology, and End Results database was used to calculate the SGC proportion. In total, 253,096 eligible patients, including 165,715 adenocarcinomas (ADCs), 87,062 squamous cell carcinomas (SCCs), and 319 SGCs, were selected to perform survival analyses. The data of 42 SGC patients from our hospital showed postoperative survival. Overall survival (OS) curves for different histological and surgical types were presented. The proportion of primary SGCs was 0.8 per 1000 patients. Patients with age ≤ 64 years old had a much higher proportion of SGC than those patients with age >64 years old. After adjusting for other confounders, among ADCs, SCCs, and SGC, SGCs had the best prognosis (HR 0.361, p < 0.001). Moreover, the 5-year OS rates of SGC patients were 55% and 7% in the group with surgery or without surgery, respectively (p < 0.001). The data of 42 patients from our hospital also showed a good survival of SGCs. Lobectomy improved the survival of SGCs significantly (adjusted HR 0.439, p = 0.016). In conclusion, pulmonary SGCs had the best prognosis among ADCs, SCCs, and SGCs. In addition, lobectomy could further improve the prognostic outcomes of SGCs.

Extranodal nasal NK/T cell lymphoma with bronchial mucoepidermoid carcinoma and lung adenocarcinoma: a case report

Extranodal nasal NK/Tcell lymphoma (ENKTCL) is a relatively rare type of non-Hodgkin's lymphoma. It is highly malignant, highly invasive, and easy to relapse. Most patients have a poor prognosis. We report a 48-year-old woman who presented with irritant dry cough that had persisted for 6 m. CT showed a mass in the right nasal cavity, with uneven density similar to soft tissue, with slight uneven enhancement. The mass and the upper, middle, and lower turbinates were not clearly demarcated, involving multiple adjacent sinus cavities, and the local bone showed osteolytic destruction; MRI showed isosignal on T1WI and slightly hypersignal on T2WI and DWI. In addition, there was a mass of soft tissue density at the bronchial opening in the right middle lobe, showing uneven and obvious enhancement; a cavity was seen in the nodule of the right lower lobe, and the adjacent pleura was stretched, showing moderate enhancement. The nasal mass was diagnosed as extranodal NK/T cell lymphoma, the right middle lobe mass was diagnosed as mucoepidermoid carcinoma, and the right lower lobe mass was diagnosed as lung adenocarcinoma. ENKTCL rarely invades the lungs. If a patient has a lung occupying lesion similar to it, biopsy confirmation should be considered to avoid misdiagnosis as a chest metastasis that affects the treatment effect.

Metastatic mucoepidermoid carcinoma to the pleura: a case report

BACKGROUND

Mucoepidermoid carcinoma is the most common malignant neoplasm arising from the salivary glands (Ali et al. in J Ayub Med Coll Abbottabad 20(2): 141-2, 2008, Xi et al. in World J Surg Oncol 10: 232, 2012). When arising from anatomic sites other than the salivary glands it can be a diagnostic challenge. Primary and metastatic mucoepidermoid carcinoma from and to the pleura are extremely rare entities that are frequently misdiagnosed as adenocarcinoma, adenosquamous carcinoma, or squamous cell carcinoma (Xi et al. in World J Surg Oncol 10: 232, 2012).

CASE PRESENTATION

We describe an unusual case of a 64-year-old Caucasian female patient with metastatic high-grade mucoepidermoid carcinoma to the pleura, morphologically resembling squamous cell carcinoma. Molecular studies of both the parotid gland and pleural tumors helped prove the metastatic nature of the pleural lesion.

CONCLUSIONS

 Metastatic mucoepidermoid carcinoma to the pleura is a rare entity, frequently misdiagnosed as squamous cell carcinoma. Differentiating between a lung primary and a metastatic disease has treatment implications and prognostic significance for the patient. When morphologic and immunophenotypic overlap exists, molecular testing can help distinguish mucoepidermoid carcinoma from other neoplasms.

Case Report: Uniportal Video-Assisted Thoracoscopic Parenchymal Sparing Secondary Carinal Resection and Reconstruction for the Treatment of Tracheobronchial Mucoepidermoid Carcinoma

Surgical resection is currently the mainstay of treatment for tracheobronchial mucoepidermoid carcinoma (TMEC). The parenchymal sparing secondary carinal resection and reconstruction for TMEC under the uniportal thoracoscopic approach has seldomly been reported in the literature. Here, we report a case of a 42-year-old male patient complaining of the incidental finding of a 1.5 × 1.2 cm neoplasm at the opening of the right bronchus intermedius and a 5.1 × 3.1 cm patchy lesion located at the left upper lobe by chest CT scans in February 2021. This patient successively underwent fiberoptic bronchoscopic biopsy of the bronchial neoplasm and CT-guided biopsy of the left upper lobe lesion. Pathological examination confirmed the diagnosis of the endobronchial mass in the right bronchus intermedius as low-grade mucoepidermoid carcinoma and left upper lobe lesion as tuberculosis. This patient successfully underwent uniportal thoracoscopic parenchymal sparing tumor resection, reconstruction of the secondary carina and lymphadenectomy at our center. Intraoperative frozen section showed no residual cancer at any bronchial stumps. Postoperative pathology indicated that no metastases were seen in any of the resected lymph nodes. The patient recovered well after surgery. He received a 9-month course of anti-tuberculosis treatment postoperatively. He did not complain of any special discomfort and there was no local recurrence at the 9-month postoperative follow-up. Although technical demanding, this case highlights that uniportal video-assisted thoracoscopic parenchymal sparing secondary carinal resection and reconstruction for TMEC is safe and feasible with the preservation of lung function and excellent outcomes.

Primary Warthin's-like adenocarcinoma of the lung: A clinicopathological, immunohistochemical, and molecular analysis of three cases

Three cases of primary pulmonary adenocarcinoma with prominent lymphoid stroma and papillary features mimicking Warthin's tumor are presented. The patients are two women and one man ages 52, 62, and 74 years respectively. Clinically, the patients presented with non-specific symptoms of cough, dyspnea, and chest pain. Imaging showed the presence of an intrapulmonary mass in the right lower, right upper and left lower lobe. All patients underwent lobectomy. Histologically, the tumors were characterized by the presence of and oncocytic papillary growth pattern embedded in a lymphoid rich background. Immunohistochemical stains for TTF-1, keratin 7, and beta-catenin were positive in the epithelial component, while CD20 showed strong positive staining in the lymphoid component. In addition, CD4 and CD8 also showed positive staining in a ratio of 3-4:1, EBER was negative. Kras mutations with wild type EGFR were identified in one case. Clinical follow-up ranging from 8 to 24 months was obtained showing that all patients are alive without recurrence. The cases herein presented represent an unusual histological variant of primary lung adenocarcinoma, which closely mimics Warthin's tumor.

Pulmonary mucoepidermoid lung carcinoma in pediatric confused with asthma

Pulmonary mucoepidermoid carcinoma (PMEC) is an extremely rare tumor of the respiratory system. The clinical presentation of PMEC is variable and nonspecific, including cough, hemoptysis, and wheezing, and may mimic other symptoms of pneumonia or asthma. Here, we present a case of PMEC in a 12-year-old male who was diagnosed with and treated for asthma for 2 years. The patient presented with symptoms of respiratory failure that did not respond to steroids or bronchodilator medications. Chest computed tomography (CT) scans revealed an endotracheal tumor. The patient underwent complete tumor resection, with no signs of recurrence 6 months after treatment.

Mutational landscape of primary pulmonary salivary gland-type tumors through targeted next-generation sequencing

OBJECTIVES

Primary pulmonary salivary gland-type tumors (PSGTs) mainly comprise of mucoepidermoid carcinoma (MEC) and adenoid cystic carcinoma (ACC), which are rare and molecularly poorly understood. This study aimed to profile the molecular alterations of PSGTs via targeted next-generation sequencing (NGS).

MATERIAL AND METHODS

Immunohistochemistry was used to screen PSGTs in 32 patients and MAML2 and MYB rearrangements were detected using fluorescence in situ hybridization. 1021-Genepanel of targeted NGS was conducted to profile genomic mutations in all the PSGT patients.

RESULTS

Among the 32 patients, 25 had MEC and 7 had ACC. MAML2 and MYB rearrangements were detected in 80.0% (20/25) of the MEC and 71.4% (5/7) of the ACC patients. Among the MEC patients, 10 (40.0%) had ≥1 mutation, and 6 of them had 11 isolated mutations with abundance >5%, namely NFE2L2, MYOD1, INPP4B, CCND2, SNTG1, HSPD1, TGFBR1, RBM10, NOTCH4, ASXL1, and PTPRD mutations. The remaining 4 patients had 9 mutations with abundance <5%, namely KMT2A, PDCD11, FLT1, BRCA2, APC, SLX4, FOXP1, FGFR1, and HRAS mutations. All the ACC patients had mutations, which were enriched in 5 pathways including the PI3K and NOTCH pathways, chromatin and cytoskeleton remodeling, and DNA damage. These results explain PSGTs harbor distinct driver features of MAML2 or MYB rearrangement, accompanied with wide mutational diversity with very low rate of somatic mutation. Several important pathways, including the NOTCH and PI3K pathways, and chromatin remodeling could be targeted to improve the survival in patients with ACC.

Primary pulmonary mucoepidermoid carcinoma: Cyto-histologic correlation and review of the literature

Preoperative fine needle aspiration diagnosis and cyto-histologic correlation of primary pulmonary mucoepidermoid carcinoma have rarely been described in detail in the literature. A 26-year old male presented at our institution with cough, bloody sputum, and a 4.3 cm left lower lobe lung mass. He was accurately diagnosed with pulmonary mucoepidermoid carcinoma on preoperative aspiration cytology. The patient subsequently proceeded to left lower lobectomy, confirming the diagnosis. In this article, we present a detailed report of primary pulmonary mucoepidermoid carcinoma describing the cytologic and histologic morphologic features, its differential diagnosis with review of the literature.

Predictive CT features for the diagnosis of primary pulmonary mucoepidermoid carcinoma: comparison with squamous cell carcinomas and adenocarcinomas

Background

To determine the predictive CT imaging features for diagnosis in patients with primary pulmonary mucoepidermoid carcinomas (PMECs).

Materials and methods

CT imaging features of 37 patients with primary PMECs, 76 with squamous cell carcinomas (SCCs) and 78 with adenocarcinomas were retrospectively reviewed. The difference of CT features among the PMECs, SCCs and adenocarcinomas was analyzed using univariate analysis, followed by multinomial logistic regression and receiver operating characteristic (ROC) curve analysis.

Results

CT imaging features including tumor size, location, margin, shape, necrosis and degree of enhancement were significant different among the PMECs, SCCs and adenocarcinomas, as determined by univariate analysis (P < 0.05). Only lesion location, shape, margin and degree of enhancement remained independent factors in multinomial logistic regression analysis. ROC curve analysis showed that the area under curve of the obtained multinomial logistic regression model was 0.805 (95%CI: 0.704–0.906).

Conclusion

The prediction model derived from location, margin, shape and degree of enhancement can be used for preoperative diagnosis of PMECs.

Mucous Gland Adenoma: The Spectrum of Growth Patterns and the Diagnostic Challenges

Mucous gland adenomas represent a small percentage of primary lung neoplasms. The accurate diagnosis of these benign tumors can be challenging not only on resected specimens but also more challenging in small bronchoscopic biopsies. If to that problem we add the issue that these tumors may also exist in the periphery of the lung, then it is easy to conclude that there is much difficulty in properly diagnosing these tumors with a core needle biopsy. Furthermore, there is little knowledge on the immunohistochemical properties and radiologic features of these tumors. Therefore, pathologists need to be aware of the spectrum of histopathologic features in these tumors and place them in perspective regarding the proper radiologic and immunohistochemical correlations. Needless to say, mucous gland adenomas exhibit a gamut of histopathologic features that can be easily confused with other more common tumor of the lung. Therefore, awareness of such features become essential in a benign tumor that is essentially diagnosed on morphologic grounds.

An eight-year-old girl with tracheal mass treated as a difficult asthma case

INTRODUCTION

Endobronchial masses such as mucoepidermoid carcinomas or carcinoid tumors are extremely rare in children and they usually originate from large bronchi. These lesions may cause wheezing and dyspnea with poor response to bronchodilators and mimic the airway obstruction caused by asthma.

CASE STUDY

We present the case of an 8-year-old girl with tracheal mucoepidermoid carcinoma who was treated as a difficult asthma case with high dose of inhaled corticosteroids.

RESULTS

The characteristic stridor, the lack of response to bronchodilators and to inhaled corticosteroid treatment, combined with the characteristic flow loop in spirometry and the hyperinflation seen on the chest radiograph, all raised the clinical suspicion of a tracheal lesion and indicated the need for flexible bronchoscopy. The bronchoscopy revealed a large lesion obstructing totally the trachea lumen. The latter finding was confirmed by chest high resolution CT. The mass was completely excised via sternotomy under cardiopulmonary bypass, and the pathologic examination showed a low-grade mucoepidermoid carcinoma of the trachea. One month after the surgery she was free of symptoms and her spirometry was normal.

CONCLUSION

Tracheal lesions mimic the symptoms of airway obstruction caused by asthma and should be always be part of the differential diagnosis in young patients with no response to asthma treatment.

Immunohistochemical Assessment of BAP1 Protein in Mucoepidermoid Carcinomas

Mucoepidermoid carcinomas are common malignant salivary gland tumors. Despite recent advances in diagnosis and treatment, there has not been much improvement in outcome of these patients, necessitating identification of novel targeted therapeutic agents. Genomic profiling of mucoepidermoid carcinomas has recently revealed aberrations in BAP1 gene. Therefore, we conducted this study to identify BAP1 loss by immunohistochemistry in these tumors. Mucoepidermoid carcinoma cases were retrieved; hematoxylin-and-eosin stained sections were reviewed. Immunohistochemistry for BAP1 was performed. Forty cases were assessed, including 25 salivary gland and 15 pulmonary mucoepidermoid carcinomas. There were 19 cases in the parotid (76%), two in submandibular gland (8%), and remaining 16% from minor salivary gland locations. Ten (40%) were low grade, nine (36%) were intermediate grade, and six (24%) were high grade mucoepidermoid carcinomas. Thirteen (86.7%) pulmonary mucoepidermoid carcinomas were tracheobronchial, while two (13.3%) were intraparenchymal; all were low grade mucoepidermoid carcinomas. On immunohistochemistry, BAP1 nuclear staining was retained in all cases (100%), irrespective of tumor location or grade. Therapeutic connotations necessitate the identification of readily applicable techniques to detect BAP1 loss in mucoepidermoid carcinomas. Using immunohistochemistry, loss of BAP1 staining was not seen in any of our cases, suggesting insensitivity of BAP1 IHC to detect aberrations at genomic level in these tumors. Analysis of BAP1 alterations by targeted sequencing may therefore be performed prior to excluding the possibility of response to BAP1-targeted therapeutics based on immunohistochemistry alone.