Prognosis of Patients with Papillary Thyroid Carcinoma Located in One Lobe Showing Lateral Node Metastasis in the Contralateral but Not Ipsilateral Compartment

Papillary thyroid carcinoma (PTC) frequently metastasizes to the lymph node in lateral compartment, which can often be detected on preoperative ultrasonography (N1b). However, PTC located in one lobe showing contralateral but not ipsilateral N1b is not common. We analyzed the clinicopathological features and prognosis of 13 patients with PTC limited in one lobe showing contralateral but not ipsilateral N1b. Sizes of the primary lesions ranged from 0.8 cm to 3.0 cm and only 2 tumors showed extrathyroid extension. Metastatic lateral node measured from 0.6 to 3.1 cm. Ten patients showed pathological central node metastasis and 5 had minute PTC lesions in the contralateral lobe. However, 3 patients did not show either of these. None of the patients have developed carcinoma recurrence or died of carcinoma to date. Taken together, PTC located in one lobe with contralateral but not ipsilateral N1b is rare and generally shows an indolent behavior. Although most patients had central node metastasis and/or minute PTC lesions in the contralateral lobe, it is also possible for carcinoma cells to metastasize directly from primary lesions to the contralateral lateral node. Total thyroidectomy with central node dissection and therapeutic MND of the contralateral compartment may be an acceptable surgical design and bilateral MND might not be mandatory.