A woman in her 50s presented with a several-month history of symptoms that included foreign body sensation in her throat, mild odynophagia, and dyspnea. She had a history of adenoid cystic carcinoma of the right submandibular gland and had undergone wide tumor excision and postoperative radiation therapy 20 years previously (60 Gy/30 fractions in 1993). She also had a history of hyperthyroidism, which was under medical control (with propylthiouracil, 50 mg/d). She stated that she did not have blurred vision, headache, seizures, or trismus. She had no family history of neurofibromatosis. A physical examination revealed a bulge in the floor of mouth, limitation of tongue movement, and no palpable lymphadenopathy. She had no suspicious spots or nodules on the skin. No neurological deficits were revealed. Postgadolinium T1-weighted magnetic resonance imaging disclosed a 7.0 × 4.0 × 3.0-cm, well-defined enhancing mass in the right side of the floor of the mouth, extending posteriorly to the tongue base and medially across the midline (Figure, A). The results of laboratory investigations were normal. Transcervical removal of the tumor was performed. The surgical specimen was a 7.2 × 5.8 × 4.3-cm encapsulated tumor composed of a homogeneous, whitish, rubbery, and glistening content (Figure, B). Microscopic examination demonstrated oval to eel-like spindle nuclei distributed in a background of generally wavy collagenous fibers and mucinous matrix (Figure, C). The specimen showed sparse cellularity and no cellular atypia. Neither mitotic figure nor tumor necrosis was found. The specimen was immunoreactive for S-100 (Figure, D), focally positive for CD34, but nonreactive for smooth muscle actin.
Chao Y, Li W, Chu P. Postradiation Tumor in the Floor of Mouth. JAMA Otolaryngol Head Neck Surg. 2015;141(7):663-664. doi:10.1001/jamaoto.2015.0882