Abstract
Sublingual lymph node metastasis of early stage squamous cell carcinoma of the tongue (SCCT) is seldom reported. Lymphatic tissue in the floor of mouth, which intervenes between the tongue and neck, will be left behind by a primary tumour resection with discontinuous neck dissection. The authors present two cases of early stage SCCT with sublingual lymph node metastasis, review the literature, and discuss the management of the floor of mouth for early stage SCCT. The authors suggest that more attention should be paid to possible sublingual lymph node metastasis for T1/T2 SCC of the ventral tongue with deeply endophytic infiltration.
Squamous cell carcinoma of the tongue (SCCT) is the most common site for oral cancer. The standard treatment for early stage tongue cancer has not been determined. In many hospitals, patients with early stage (T1/T2N0M0) SCCT are treated with transoral resection of the tumour, with or without discontinuous elective neck dissection. There are some lymphatic tissues in the floor of mouth that will not be dissected using this discontinuous approach. They include lymph nodes in the sublingual gland, which may be sentinel nodes for some tongue cancers. The authors present two metastatic cases of early tongue cancer from Peking Union Medical College Hospital and discuss the management of the floor of the mouth for early tongue cancer.
Case 1
A 47-year-old woman presented with a 2-month history of right ventral tongue pain and ulcer. Examination showed a 1.5 cm endophytic infiltrated ulcer on the right ventral side of her tongue, with no palpable mass in the neck. An incision biopsy revealed well differentiated SCC. A computed tomography (CT) scan was negative, and the preoperative stage was T1N0M0. A transoral wide local excision with 1.5 cm margins and a discontinuous supraomohyoid neck dissection were performed. A frozen section of the resection margins was negative. Postoperative paraffin section pathology was reported as well differentiated SCC, tumour thickness 1.0 cm, all resection margins were negative, and the neck lymph nodes were negative (0/31). Postoperative healing was uneventful, and the patient was discharged and followed up.
7 months after the operation, a 2 × 2 cm soft mass was found at Level III of the contralateral neck. Intraoral and ipsilateral cervical examination showed no abnormality. Magnetic resonance imaging (MRI) showed a cystic mass in the middle of the left lateral neck; there were no other positive findings. An excisional lymph node biopsy was done and showed metastatic SCC. Positron emission tomography (PET) was performed and revealed a hypermetabolic focus in the right side (ipsilateral side of primary tongue cancer) of the floor of the mouth, and lymph node metastasis was suspected ( Fig. 1 ). It was not palpable by bimanual examination. An exploratory operation in the right floor of the mouth was carried out through a cervical incision in the submandibular region. A frozen section confirmed SCC, and a wide local resection and contralateral radical neck dissection were performed at the same time. The final pathology report showed well differentiated SCC in the right floor of the mouth, surrounded by infiltrating lymph cells; no further metastatic carcinoma was found in the lymph nodes of the left side of the neck. Postoperative radiotherapy was undertaken (60 Gy).
6 months after the second operation, the carcinoma relapsed in the right submandibular region and metastasized to the left anterior neck region with invasion of the left thyroid gland. Wide local resection, internal carotid reconstruction, and subtotal thyroidectomy were carried out with reconstruction using a pectoralis major myocutaneous flap. The patient died 3 months later because of multiple organ failure.
Case 2
A 42-year-old man presented with an ulcer and mass in the right ventral tongue of 5 months’ duration. An incisional biopsy revealed moderately differentiated SCC. The patient was admitted to hospital, and a 3 × 3 cm endophytic infiltrating tumour was found in the ventral tongue, with no palpable mass in the neck, and no suspect lymph node on CT scan. The preoperative diagnosis was T2N0M0. A composite resection was done with extensive resection of partial tongue, floor of the mouth and an in-continuity supraomohyoid neck dissection, the oral defect was reconstructed with a forearm flap. The postoperative pathology reported well-to-moderately differentiated SCC, 1.6 cm tumour thickness, all margins negative, there were no lymph node metastases with the exception of one lymph node in the floor of the mouth with extracapsular spread (1/3 floor of mouth, 0/32 neck). The patient recovered uneventfully, and postoperative radiotherapy was performed (60 Gy). After 2 years of follow up there is no evidence of local or regional recurrence and distant metastasis ( Fig. 2 ).
Case 2
A 42-year-old man presented with an ulcer and mass in the right ventral tongue of 5 months’ duration. An incisional biopsy revealed moderately differentiated SCC. The patient was admitted to hospital, and a 3 × 3 cm endophytic infiltrating tumour was found in the ventral tongue, with no palpable mass in the neck, and no suspect lymph node on CT scan. The preoperative diagnosis was T2N0M0. A composite resection was done with extensive resection of partial tongue, floor of the mouth and an in-continuity supraomohyoid neck dissection, the oral defect was reconstructed with a forearm flap. The postoperative pathology reported well-to-moderately differentiated SCC, 1.6 cm tumour thickness, all margins negative, there were no lymph node metastases with the exception of one lymph node in the floor of the mouth with extracapsular spread (1/3 floor of mouth, 0/32 neck). The patient recovered uneventfully, and postoperative radiotherapy was performed (60 Gy). After 2 years of follow up there is no evidence of local or regional recurrence and distant metastasis ( Fig. 2 ).
