|Year : 2014 | Volume
| Issue : 2 | Page : 384-386
A rarely seen mucoepidermoid carcinoma of the left main bronchus
Mustafa Kuzucuoglu1, Yekta Altemur Karamustafaoglu1, İrfan Cicin2, Yener Yoruk1
1 Department of Thoracic Surgery, Faculty of Medicine, Trakya University, Edirne, Turkey
2 Department of Medical Oncology, Faculty of Medicine, Trakya University, Edirne, Turkey
|Date of Web Publication||14-Jul-2014|
Yekta Altemur Karamustafaoglu
Department of Thoracic Surgery, Faculty of Medicine, Trakya University, Balkan Yerleskesi, 22030, Edirne
Source of Support: None, Conflict of Interest: None
Mucoepidermoid carcinomas (MEC) are rare malignant tumors that originate in the submucosal bronchial glands, and complete resection usually correlates with favorable prognosis. A 54-year-old male patient was diagnosed with high-grade MEC in the left main bronchus via bronchoscopy. After the patient was diagnosed with metastatic lung cancer, chemotherapy was started. Two years after the diagnosis, the patient is still alive.
Keywords: Chemotherapy, metastasis, mucoepidermoid carcinoma
|How to cite this article:|
Kuzucuoglu M, Karamustafaoglu YA, Cicin &, Yoruk Y. A rarely seen mucoepidermoid carcinoma of the left main bronchus. J Can Res Ther 2014;10:384-6
| > Background|| |
Mucoepidermoid carcinomas (MECs) are a distinct and rare form of malignant tumors that originate in the submucosal bronchial glands and are more common in the segmental bronchi than in the trachea or main bronchi. ,,, Although, they can be found in people from all age ranges (3 to 78 years -old), they usually are seen in people who are in their 30s and 40s. MECs are usually low-grade tumors rather than benign neoplasms, the term "bronchial adenoma" is a miscall and should be excluded, and good prognosis can be obtained by surgical resection. , Patients with low-grade MEC generally have an excellent prognosis, and chemotherapy or radiotherapy is considered unnecessary. However, high-grade MECs demonstrate invasion into the bronchial submucosa and lymph nods, invade the pulmonary parenchyma and it have not yet been established effective treatment for high-grade tumors.  Herein, we present a patient with MEC, and emphasized the clinical features, treatment results and prognosis.
| > Case report|| |
A 54-year-old male patient who complained of cough, chest pain, and weight loss over the course of 1 month was admitted. Chest X-ray revealed a mass in the left hilar localization and chest computerized tomography (CT) showed a central mass measuring 37 × 24 mm in diameter [Figure 1]a. Bronchoscopy revealed an endobronchial mass, 3 cm away from the carina, overlapping from the bronchus of the left upper lobe towards the left main bronchus. Punch biopsies were performed from the mass and bronchoalveolar lavage was carried out.
|Figure 1: (a) Thorax computerized tomography (CT) before chemotherapy (b) Thorax CT after chemotherapy|
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Immunohistochemical staining for cytokeratin 5/7 and p63 showed positive and negative for TTF-1, respectively. Histopathological examination of the tissue reported the diagnosis as high-grade MEC.
Positron emission tomography-CT showed a hilar mass surrounding the left main bronchus extending towards the left upper and lower lobe bronchi and with uptake of 18F-fluoro-deoxy-glucose (FDG) (SUVmax = 7.4). In addition, the pathological FDG uptake was found in the right paratracheal, the right tracheobronchial, and the bilateral bronchopulmonary lymphatic nodes. It was also found in the parenchymal nodular lesions in the left lower lobe [Figure 2]. An abnormal FDG uptake was also detected in segment V of the liver, in the spinal process of the third cervical vertebra, on the edge of the right acetabulum, and in the sigmoid colon, suggesting the presence of metastases. Based on these findings, a colonoscopy was performed; however, no endoluminal disease was found. The patient was considered to be stage IV lung cancer and was sent to the medical oncology department.
Having diagnosed the patient with metastatic lung cancer, the medical oncology department planned six cycles of chemotherapy with cisplatin and docetaxel. Chemotherapy was started, and a clear regression of the mass was seen in the contrasted thoracic and abdominal CT scans performed 15 days after the third cycle, and the treatment was continued until completion of the sixth cycle. After the sixth cycle chemotherapy was done CT scan then revealed no disease progression [Figure 1]b. However, on the development of cranial metastasis in the 20 th months, three cycles of methotrexate were started. Methotrexate dosage was 40 mg/m 2 intravenously on the 1 st and 8 th days. Epidermal growth factor receptor (EGFR) was negative in the present study. Therefore, the treatment was not planned. Two years after the diagnosis, the patient is still alive.
| > Discussion|| |
MEC is a malignant tumor originating in the bronchial glands. MEC was first described in 1952 by Smetana.  In the World Health Organization's histological classification of lung tumors, MECs belong in the main group of malignant epithelial tumors and the subgroup of salivary gland tumors. Histologically, they are classified as low-grade and high-grade. It may be difficult to differentiate high-grade MECs from adenosquamous carcinomas, histologically. The presence of transient low-grade carcinoma spaces in the high-grade MECs may be helpful in establishing a differential diagnosis. In pediatric and adolescent patients, the tumor is well-differentiated, low-grade, and usually has a benign course without relapses or metastasis. In two larger series, Heitmiller et al.  reported 18 cases and Yousem et al.  reported 58 cases. In the older age group, high-grade MEC is seen more frequently.  Some reports, have noted a male predominance for high-grade MEC. Most of the cases are admitted with symptoms such as cough, dyspnea, wheezing, and obstructive pneumonia. , Pain, weight loss, and other general illness symptoms and findings are seen in aggressive and diffuse diseases. ,
MECs usually arise from the central and segmentary bronchi, and the symptoms are related to that region.  In the radiological images, atelectasis and obstructive pneumonia findings in the distal part of the bronchus are typical. The tumors may also be seen as nodular and cavitary lesions. ,
In low-grade tumors, conservative surgical treatment is preferred. Regional lymphatic node metastases have been seen in less than 5% of these tumors. In high-grade tumors, the prognosis is variable. Although, high-grade MECs are thought to have a better prognosis than non-small cell lung carcinomas, they also should be treated by radical surgical treatment. 
Yang et al.  reported on 11 patients in their study the 5-year survival of eight patients with high-grade MEC tumors was 25% and the median survival was 23.5 months. Six patients with high-grade tumors received adjuvant therapy, but their prognoses were reported as poor. In its conclusion, the study noted that histological grading of the MEC and the ability to perform an anatomic resection are the two most important factors that affect prognosis, and adjuvant therapy does not seem to be effective in patients with high-grade MEC. The survival time for our patient was 24 months, and he only received chemotherapy.
Li et al.  recommended the bronchoscopic laser method as an alternative to radical surgery in cases confined to the bronchus, and they successfully used Nd-YAG laser bronchoscopically in two cases. In their study, Singh et al.  recommended that, in the treatment of both low-grade and high-grade MECs, resection should be performed first; they also recommended that an additional excision be performed if the surgical border remained positive. Furthermore, they indicated that no adjuvant therapy is needed if the MEC tumor is low-grade and the patient is eligible for surgical treatment.
Metastases in MECs occur by lymphatic or hematogenous pathways. Metastases are most frequently seen in the regional lymphatic nodes (48%), bone (25%), distant lymphatic nodes (18%), and the adrenal gland, cerebral, and skin (14%).  As Singh et al.  stated, radiotherapy and chemotherapy are preferred in patients whose surgical margins remained positive and whose tumors cannot be re-resected, or in inoperable patients who already are metastatic at the time of diagnosis. In those patients, cisplatin, docetaxel, gemcitabine, adriamycin, and pemetrexed are preferred chemotherapy combinations. In our case, six cycles of cisplatin combined with docetaxel were administered, and a clear radiological response was obtained.
Treatment involving EGFR tyrosine kinase inhibitors showed promising outcome for MEC patients.  However, EGFR expression was not common either in the lung or salivary glands, which differed from the results of previous studies. ,
| > Conclusion|| |
MECs of the lung arise from the tracheobronchial glands, are rarely seen, and have a malignant potential, although, the tumors are usually low-grade. Surgery is the treatment of choice for the resectable tumors. Combined chemotherapy protocols are used in metastatic or inoperable tumors. There are no randomized controlled trials studying the profit of adjuvant chemotherapy in MECs of the lung and given the rarity of these tumors, such studies will likely never be designated.
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[Figure 1], [Figure 2]