A case of pleomorphic adenoma in the sublingual gland

Although pleomorphic adenoma is the most common benign salivary gland tumor, it rarely occurs in the sublingual glands. A case of pleomorphic adenoma that arose in a sublingual gland is presented. A 60-year-old man had been aware of a mass in the right side of the floor of the mouth for 6 months. When he sought treatment, a painless, elastic, hard, movable, well-circumscribed tumor mass, approximately 2 cm in diameter, was found in the right mouth floor. Magnetic resonance imaging showed a comparatively well-defined mass (19 mm × 12 mm) with inhomogeneous internal structure. A low-intensity area was seen on T1-weighted images, and a mild low-to-high intensity area was seen on T2-weighted images; this corresponded with the right sublingual gland. Examination of a biopsy specimen confirmed the diagnosis of pleomorphic adenoma, and the tumor and sublingual glands were resected under general anesthesia. On histopathology, the tumor was identified in the sublingual gland tissue; it was completely surrounded by a thin fibrous capsule, and tumor cells had not invaded the capsule. The histopathological diagnosis was pleomorphic adenoma. No evidence of recurrence was seen at 1 year after surgery.