Mucoepidermoid Carcinoma of the Tongue Base: A Case Report

The major and minor salivary glands of the head and neck are the site of a diverse group of both benign and malignant neoplasms. Minor salivary glands are small submucosal glands, located throughout the upper aerodigestive tract. Mucoepidermoid carcinoma (MEC) is a common malignant salivary gland neoplasm presumed to arise from the reserve cells of salivary gland ducts. The most common site for this malignancy is the parotid gland (89.6%), followed by the submandibular gland (8.4%).¹ MEC rarely has been reported in the tongue base.² We present a case of MEC of the tongue base and discuss its clinical presentation and management.

Case Report

A 40-year-old woman presented to Alexandria Main hospital ENT clinic complaining of slowly progressive dysphagia. The symptoms were persistent for 4 months, and the dysphagia was more for solids than liquids. Standard clinical examination revealed the presence of a large mass with a smooth surface in the midline of the tongue base (BOT). Computed tomography (CT) neck with contrast in both axial and sagittal reconstruction and magnetic resonance imaging (MRI) confirmed the BOT mass lesion ( Figure 1 ). No cervical lymphadenopathy was detected. The thyroid gland was visualized in its normal position and no ectopic thyroid tissue could be detected. Informed consent was obtained from the patient prior to surgery. The study was approved by the ethical committee of the Alexandria Faculty of Medicine. Transoral surgical excision under general anesthesia was done with the use of bipolar cautery for proper hemostasis ( Figure 2 ). Histopathological examination revealed a low-grade mucoepidermoid carcinoma originating from the BOT minor salivary glands. After confirming the diagnosis, a second transoral surgery was done to excise a cuff of BOT tissue to obtain clear surgical margins. No further malignancy was detected in the excised tissue. The postoperative period was uneventful, and the patient was discharged home on the second postoperative day. Follow-up after 3 and 6 months revealed no recurrence.

Figure 1.

MRI sagital view showing base of tongue mass.

Figure 2.

The mass gross appearance after excision.

Discussion

Salivary gland tumors account for about 3% to 5%³ of all tumors of the oropharynx and the majority of such tumors arising from the minor salivary glands. Mucoepidermoid carcinoma is the most common malignant neoplasm encountered in the parotid gland and the most prevalent salivary cancer overall. In the current work, we present a case of MEC originating from the tongue base. The origin of this malignancy is the minor salivary glands found in the tongue base. Although it is a rare occurrence, it was reported in other studies.² In the past, low-grade MEC with well-defined glandular elements were not considered malignant because they metastasize so infrequently. In contrast, high-grade mucoepidermoid carcinoma may be nearly devoid of glandular features under the microscope, rendering it hard to distinguish from primary squamous carcinoma without the use of special stains to identify mucin-producing cells.⁴ The histological characteristics and the natural tendency of this type of tumor to infiltrate surrounding tissue and cause lymph node metastases highlight the importance of a radical surgical approach, often combined with a neck dissection.⁵ After surgery, radiotherapy may reduce the risk of locoregional recurrence in cases of advanced tumor with positive resection margins or with high-grade malignancy.⁵

Conclusions

Malignant tumors arising from the minor salivary gland are rare clinical entities but should be considered in the differential diagnosis of BOT mass.

Author Contributions

Mohamed Zahran, primary author, design of the work, data analysis, reviewing of the draft, final approval; Ahmed Youssef, coauthor, data analysis, helping in editing of the draft.

Disclosures

Competing interests: None.

Sponsorships: None.

Funding source: None.