Abstract
Myoepithelial carcinoma (MEC), a rare malignant salivary gland tumor, was first classified as a separate neoplasm by the World Health Organization (WHO) in 1991. The tumor represents less than 1% of all salivary gland neoplasms. MEC occurs most frequently in the parotid gland (75%), and approximately 10% in the submandibular gland, and there have been no previous reports of MEC arising from the sublingual gland. Herein, we report a case of MEC occurring in the sublingual gland.
A 67-year-old male came to our hospital in January of 2006, complaining of a swelling on the left side of the floor of the mouth. Clinical examination revealed a 30 × 20 × 10mm elastic, hard, non-tender, submucosal mass on the left side of the floor of the mouth. The mass had poor mobility, but no ulceration was seen on the surface of the mucosa.
Magnetic resonance imaging (MRI) showed an ovoid form mass with a bright mixture of hyper- and hypo-intense signals on T1-weighted images. No signs of mandibular bone invasion were detected. The resected specimen showed a lobulated shape and it extended from the sublingual gland into the surrounding tissues. Immunohistochemical analysis indicated that the tumor cells were positive for S-100 protein, SMA, pan-keratin, CK19, MUC-I, Calponin, and Vimentin. The pathological diagnosis was myoepithelial carcinoma of the sublingual gland. During the follow-up for 2 years and 9 months, there was no clinical or radiological evidence of loco-regional recurrence or distant metastasis.
