Surgical outcomes of pulmonary mucoepidermoid carcinoma: A review of 41 cases

Left lower lobe sleeve resection for the clear cell variant of pulmonary mucoepidermoid carcinoma: A case report

BACKGROUND

Pulmonary mucoepidermoid carcinoma (PMEC) is a rare malignancy that arises from minor salivary glands within the tracheobronchial tree. The clear cell variant of PMEC is exceptionally uncommon and presents notable diagnostic challenges, primarily attributable to its morphological similarity to other tumors containing clear cells.

CASE SUMMARY

A 22-year-old male, formerly in good health, came in with a two-month duration of persistent cough and production of sputum. Subsequent imaging and bronchoscopy examinations revealed a 2 cm tumor in the distal left main bronchus, which resulted in complete atelectasis of the left lung. Further assessment via positron emission tomography/computed tomography scans and endoscopic biopsy confirmed the primary malignant nature of the tumor, characterized by clear cell morphology in most of the tumor cells. The patient underwent a left lower lobe sleeve resection accompanied by systematic mediastinal lymph node dissection. Molecular pathology analysis subsequently revealed a CRTC3-MAML2 gene fusion, leading to a definitive pathological diagnosis of the clear cell variant of PMEC, staged as T2N0M0. After surgery, the patient experienced a smooth recovery and exhibited no signs of recurrence during the one-and-a-half-year follow-up period.

CONCLUSION

This article describes an unusual case of a clear cell variant of PMEC characterized by the presence of a CRTC3-MAML2 gene fusion in a 22-year-old male. The patient underwent successful left lower lobe sleeve resection. This case underscores the distinctive challenges associated with diagnosing and treating this uncommon malignancy, underscoring the importance of precise diagnosis and personalized treatment strategies.

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.

Mucoepidermoid carcinoma of the lung with hemoptysis as initial symptom: A case report

BACKGROUND

Mucoepidermoid carcinoma of the lung is a rare malignant tumor, accounting for 0.1%-0.2% of all lung malignancies. It is a primary salivary gland tumor of the lung. Surgical resection is the primary treatment for pulmonary mucoepidermoid carcinoma, for which there has been no standardized treatment strategy. This article reports a case of a young woman with pulmonary mucoepidermoid carcinoma with hemoptysis as the first symptom.

CASE SUMMARY

A 24-year-old female patient presented with "4 d of hemoptysis" as the chief complaint. She had no special history and denied any smoking or drinking history. Physical examination revealed that the vital signs were stable and scattered small wet rales were heard in the left lung. After admission, the lung tumor markers were checked, and no abnormalities were found. After completing the bronchoscopy, a spherical lesion was observed at the main bronchus 1.5 cm away from the protubercle, with obvious pulsation and little blood seepage on the surface, and histopathological biopsy results showed acute and chronic inflammation. She was transferred to the Department of Thoracic Surgery for surgical treatment on the 16th day after admission. After exclusion of surgical conjunctures, the patient underwent resection of the tumor in the left main bronchus with single-pore video-assisted thoracic surgery on the 19th day after admission. The postoperative histopathological biopsy results showed mucoepidermoid carcinoma of the lung. The patient and her family refused to complete genetic testing and she was discharged from the hospital on the 8th day after surgery. During the follow-up period, the patient experienced shortness of breath after feeling active and had no special discomfort.

CONCLUSION

We have documented a case of moderately differentiated mucoepidermoid lung cancer with hemoptysis as the first symptom to improve clinicians' understanding of the disease and provide a new dimension of thinking for its future diagnosis and treatment.

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.

Primary endo-bronchial muco-epidermoid carcinoma in a 22-year-old female: A case report

INTRODUCTION

Muco-epidermoid carcinomas are primarily the subtypes of salivary gland tumors that can rarely originate within the respiratory tract. Our case highlights the occurrence of an unusual, localized, endo-bronchial muco-epidermoid cancer. We aim to strengthen the evidence of occurrence of this distinct variety of lung cancer in our country as little is known about this rare subclass of lung cancer.

CASE PRESENTATION

We report a case of a 22-year-old female patient, belonging to Karachi, Pakistan, who presented with respiratory symptoms and upon work-up, was diagnosed with a low-grade, localized muco-epidermoid carcinoma of the lung. She underwent surgical resection successfully and was advised to get evaluated for adjuvant radiotherapy.

CLINICAL DISCUSSION

Localized low-grade MEC respond well to surgical resection in contrast to high-grade MEC which is associated with poor prognosis thus requiring adjuvant radiotherapy to improve survival outcomes.

CONCLUSION

Lung cancers can be unusually of muco-epidermoid origin. It has been uncommonly found in the world including Pakistan. Special attention with validated data is therefore needed, for developing guidelines for the optimal management of such neoplasms.

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.

Diagnostic Value of MAML2 Rearrangements in Mucoepidermoid Carcinoma

Mucoepidermoid carcinoma (MEC) is often seen in salivary glands and can harbor MAML2 translocations (MAML2+). The translocation status has diagnostic utility as an objective confirmation of the MEC diagnosis, for example, when distinction from the more aggressive adenosquamous carcinoma (ASC) is not straightforward. To assess the diagnostic relevance of MAML2, we examined our 5-year experience in prospective testing of 8106 solid tumors using RNA-seq panel testing in combinations with a two-round Delphi-based scenario survey. The prevalence of MAML2+ across all tumors was 0.28% (n = 23/8106) and the majority of MAML2+ cases were found in head and neck tumors (78.3%), where the overall prevalence was 5.9% (n = 18/307). The sensitivity of MAML2 for MEC was 60% and most cases (80%) were submitted for diagnostic confirmation; in 24% of cases, the MAML2 results changed the working diagnosis. An independent survey of 15 experts showed relative importance indexes of 0.8 and 0.65 for "confirmatory MAML2 testing" in suspected MEC and ASC, respectively. Real-world evidence confirmed that the added value of MAML2 is a composite of an imperfect confirmation test for MEC and a highly specific exclusion tool for the diagnosis of ASC. Real-world evidence can help move a rare molecular-genetic biomarker from an emerging tool to the clinic.

Photodynamic therapy for pulmonary mucoepidermoid carcinoma

Pulmonary mucoepidermoid carcinoma (PMEC) are rare, accounting for 0.1–0.2% of all malignant lung tumors. Furthermore, endobronchial lesions are rare and are more commonly found in the segmental or lobar bronchi. We present, to the best of our knowledge, the first case of successful treatment with photodynamic therapy (PDT) for PMEC. A 77-year-old male presented with cough and hemosputum for 4 months. Chest computed tomography showed a mass in the right intermediate bronchus. Endobronchial biopsy revealed a diagnosis of PMEC. An optimal surgical technique to preserve respiratory function was desirable as most of the tumor emerged from the bronchial glands in the central airways and was of low-grade type. Hence, PDT was performed. Repeat bronchoscopies were performed 5 years after the PDT and showed no evidence of tumor recurrence. PDT is more likely to be effective for low-grade PMECs that are visible on bronchoscopy.

Clinical Characteristics and Prognosis of Patients With Pulmonary Mucoepidermoid Carcinoma: A SEER-Based Analysis

Background

Primary pulmonary mucoepidermoid carcinoma (PMEC) is an extremely rare malignancy. Its clinical characteristics and prognosis are not fully understood. This study evaluated clinical characteristics and prognostic factors of PMEC and established a nomogram to predict its 1-, 3-, 5- and 10-year cancer-specific survival (CSS) rates.

Methods

In the Surveillance, Epidemiology, and End Results database from January 1, 2016 to December 31, 2016, patients pathologically diagnosed with PMEC were identified. Kaplan-Meier analysis and Cox regression were performed to evaluate the CSS stratified by different covariates. A predictive nomogram model was built and validated by the concordance index (C-index) and calibration curves.

Results

A total of 585 PMEC patients were identified. A total of 408 (70%) of patients were placed into the training cohort, and 177 (30%) patients were placed into the validation cohort. The 5- and 10-year CSS rates of stage I-II PMEC patients were 91.4 and 88.9, respectively. The 1-, 3- and 5-year CSS rates of stage III-IV PMEC were 56.5, 39.45, and 32.1%, respectively. Survival curves showed that older age, large tumor size, poor differentiation, and high TNM stage were associated with a significantly worse prognosis. CSS outcomes were significantly better in patients who received surgical treatments (surgical alone, surgery plus radiation and/or chemotherapy). Patients who received radiation and/or chemotherapy had the worst prognosis. Multivariate Cox results revealed that covariates, including age, tumor laterality, tumor sizes, pathological differentiation, lymph node metastasis, distant metastasis, TNM stage and therapy, were independent prognostic factors for PMEC. These factors were used to construct a nomogram. The C-index of the nomogram was 0.921. The calibration curve presented favorable consistency between the predicted CSS and actual observations. This nomogram was validated by the validation cohort. The C-index of the validation cohort was 0.968.

Conclusion

Age, bilateral tumors, tumor size, pathological differentiation grade, lymph node metastasis, distant metastasis, TNM stage and therapy were independent prognostic factors of PMEC patients. The first nomogram for predicting the CSS of PMEC was built and validated, showing its potential value in practice.

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.

Total Lung-sparing Surgery for Tracheobronchial Low-grade Malignancies

BACKGROUND

Total lung-sparing tracheobronchial sleeve resections are a step forward in the treatment of low-grade bronchial tumors in which minimal resection margins are required to achieve complete control of the disease.

METHODS

This study retrospectively collected data on patients who underwent total lung-sparing procedures for low-grade tracheobronchial tumors at 2 thoracic surgical centers from January 1984 to October 2019.

RESULTS

The study included 98 patients, 46 -female (47%) and 52 -male (53%), with a median age of 39 years (range, 7 to 70 years). Thirty-four patients underwent operative endoscopy before surgery (32 had laser treatment, and 2 had endobronchial stenting). The surgical resections were as follows: 9 (9%), tracheal carina; 18 (18%), second carina; 31 (32%), left main bronchi; 25 (26%), right main bronchi; and 15 (15%), intermediate bronchus. The median length of the resected bronchus was 2.2 cm. The median postoperative in-hospital stay was 8 days, and no perioperative mortality was observed. Postoperative complications were recorded in 26-patients (27%). The final histologic classification was as follows: 37 typical carcinoids (38%); 10 atypical carcinoids (10%); 29 adenoid cystic carcinomas (30%); 15 mucoepidermoid carcinomas (15%); 6 inflammatory myofibroblastic tumors (6%); and 1 glomic tumor (1%). Twenty-two patients had positive resection margins and underwent adjuvant radiotherapy. Three patients with adenoid cystic carcinoma had recurrences (1 local and 2 systemic). After a median follow-up time of 54.5 months (range, 4 to 360 months), the overall actuarial 5-year survival was 97%.

CONCLUSIONS

Total lung-sparing tracheobronchial sleeve resection for low-grade malignant disease requires advanced surgical skills, but the hospital morbidity and mortality are very low. This technique is adequate and safe for highly selected patients with low-grade endobronchial malignant diseases, and its use should be encouraged in experienced centers.

Treatment outcomes of patients with tracheobronchial mucoepidermoid carcinoma compared with those with adenoid cystic carcinoma

OBJECTIVE

Tracheobronchial mucoepidermoid carcinoma (TMEC) is an extremely rare salivary gland-type neoplasm. We aimed to explore the clinical characteristics and prognosis of TMEC and to compare them with those of another rare salivary gland-type neoplasm, tracheobronchial adenoid cystic carcinoma (TACC).

METHOD

We performed a retrospective review of all patients pathologically diagnosed with TMEC between 1965 and 2017 at our institution. We reviewed the patients' clinical characteristics, treatment methods and outcomes and compared the results of TMEC and TACC patients.

RESULTS

A total of 115 consecutive patients, including 107 who underwent surgery and 8 who received nonoperative therapy, were included in our study. The 1-, 2-, and 5-year survival rates were 97.89%, 94.17%, and 90.50%, respectively, in the surgical group and 83.33%, 41.67% and 0.00%, respectively, in the nonoperative group. The multivariate analysis showed that N stage was an independent prognostic factor for overall survival (OS). TMEC patients were younger, had a shorter complaint duration, had fewer symptoms, had more bronchial tumors, and were more likely to undergo surgical treatment and achieve an R0 resection (surgically treated patients) than TACC patients; furthermore, TMEC patients had a significantly better OS than TACC patients (P < 0.050).

CONCLUSIONS

TMEC has different characteristics and a better prognosis than TACC, which may reflect the different biological behaviors of these two salivary gland neoplasms. Radical treatment and close follow-up are critical for surgically treated TMEC patients with lymph node metastasis.

Curious case of primary pulmonary mucoepidermoid carcinoma

Pulmonary mucoepidermoid carcinoma (MEC) is an uncommon tumor constituting only 0.1% to 0.2% of all lung carcinoma. It is classified under “salivary gland type” tumors in the World Health Organization (WHO) classification of lung cancers. It generally carries a better prognosis than the more common small cell and nonsmall cell lung carcinomas. It is pathologically classified into high-grade and low-grade tumors. High-grade tumors are usually unresectable at presentation. However, surgery is the mainstay of treatment, which aims at surgically negative margins for a complete cure. In our patient, pulmonary MEC presented with intrathoracic mass with pericardial effusion. It came out to be low-grade neoplasm, which was treated with platinum-based doublet chemotherapy and responded well with near-total disappearance of tumor, like a vanishing lung tumor.

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.

Big data, big contributions: outcomes research in thoracic surgery

In recent years, analysis of registry data has defined clinically significant practice patterns and treatment strategies that optimize cancer care for thoracic surgery patients. These higher-order outcome studies rely on large patient cohorts that minimize the risk of selection bias and allow for a powered analysis that is not achievable with single- or multi-institutional data. This review uses recent study examples to highlight important contributions to our knowledge of thoracic surgery and describes how outcomes research using large data can address high impact clinical questions.

A Comparative Study of Primary Adenoid Cystic and Mucoepidermoid Carcinoma of Lung

Background

Pulmonary mucoepidermoid carcinoma (PMEC) and pulmonary adenoid cystic carcinoma (PACC) are the two major types of primary salivary gland-type (PSGT) lung cancers. The demographic profile, clinicopathological features, and predictors of survival as an overall group have not been described for PSGT cancers of lung.

Methods

In this study, we analyzed demographic, clinical, and survival data from 1,032 patients (546 PMEC and 486 PACC) who were diagnosed of PSGT lung cancer in the Surveillance, Epidemiology and End Results database from 1973 to 2014.

Results

The PSGT constituted 0.09% of all lung cancers with age-adjusted incidence rate of 0.07 per 100,000 person-years and change of −32% from 1973 to 2014. The incidence of PMEC was slightly higher than PACC but there were no differences in the age and sex distribution. PACCs (55%) were significantly higher at trachea and main bronchus while PMECs were more common at peripheral lungs (85%). Most of the tumors were diagnosed at an early stage and were low grade irrespective of histology. As compared to PMEC, significantly higher number of patients with PACC underwent radical surgery and received adjuvant radiation. The 1- and 5-year cause-specific survival was 76.6 and 62.8%, respectively. On multivariate analysis, the survival was affected by age at diagnosis, tumor stage, histological grade, period of diagnosis, and surgical resection. The histology showed strong interaction with time and hazard ratio of patients with PACC was significantly worse than patients with PMEC only after 5 years.

Conclusion

The incidence of pulmonary PSGT cancer is 7 cases per 10 million population in the United States and is decreasing. There was no difference between demographic profile of patients with PMEC and PACC but pathological features were diverse. The difference in the survival of patients with the two histological types surfaced only after 5 years when survival of patients with PMEC was better than PACC.

Primary Salivary Type Lung Cancers in the National Cancer Database

BACKGROUND

Primary salivary type lung cancers such as adenoid cystic carcinoma (ACC) and mucoepidermoid carcinoma (MEC) are uncommon primary lung tumors that, given their rarity, remain incompletely understood. This study aimed to characterize the management and outcomes associated with these less common pulmonary malignancies.

METHODS

Patients in the National Cancer Database diagnosed with primary lung and bronchial (not tracheal) MEC and ACC between 2004 and 2014 were identified. Adjusted mortality risk of surgically managed patients was evaluated in multivariable Cox proportional hazards regression models.

RESULTS

In all, 699 MEC patients and 424 ACC patients were identified. The MEC tumors were smaller (mean size 3.1 cm versus 3.8 cm, p < 0.001), less likely to have lymph node metastases (16% versus 38%, p < 0.001), and less likely to undergo pneumonectomy (9% versus 39%, p < 0.001) compared with ACC. Adjusted Cox models of the surgically managed subset of MEC patients identified high tumor grade (hazard ratio [HR] 3.0, 95% confidence interval [CI]: 1.31 to 7.1, p = 0.01), tumor size greater than 4 cm (HR 6.7, 95% CI: 2.0 to 22.0, p = 0.01), and wedge resection (HR 3.7, 95% CI: 1.1 to 12.0, p = 0.03) to be associated with increased risk of death. For ACC patients, incomplete tumor resection, R1 versus R0 (HR 4.0, 95% CI: 1.5 to 10.6, p = 0.006), and distant metastases (HR 12.6, 95% CI: 2.5 to 64.4, p = 0.002) were associated with increased mortality.

CONCLUSIONS

Pulmonary MEC and ACC appear to have distinct physical and oncologic attributes in the National Cancer Database. Although the overall prognosis appears to be favorable, there are subsets of primary salivary type lung cancers with increased mortality risk, and efforts should be made to completely resect these tumors.

Clinicopathological characteristics and molecular analysis of primary pulmonary mucoepidermoid carcinoma: Case report and literature review

Primary pulmonary mucoepidermoid carcinoma (PMEC) is extremely rare. Herein, we report a case of a 71‐year‐old male patient with high‐grade PMEC involving the right upper lobe that was successfully resected via lobectomy. As a result of invasion into the pleural and paratracheal lymph nodes, four cycles of adjuvant chemotherapy with paclitaxel and carboplatin were administered. There were no signs of relapse during 10 months of follow‐up. Furthermore, we reviewed the literature and summarized the surgical approaches, prognostic factors, and underlying genetic mechanisms of PMEC, which will benefit clinical treatment.