Parapharyngeal Metastasis of Papillary Thyroid Carcinoma

Nodal involvement of papillary thyroid carcinoma (PTC) commonly occurs in the paratracheal region and the internal jugular chain. Lymph node metastasis in the parapharyngeal space (PPS) is rare. In this report, we describe our experience and surgical outcomes of patients with PPS metastasis of PTC. Clinical data of patients with PTC who underwent surgery at our institution between January 2006 and December 2013 were retrospectively reviewed, and 22 patients with PPS metastasis were enrolled. There were 2 primary and 20 secondary cases of PPS metastasis. Involvement of the jugular nodes was noted before or at the time of PPS metastasis detection in all cases. A transcervical surgical approach with partial resection of the mandibular angle was performed in 21 patients, while 1 patient underwent extirpation of the PPS metastasis via a transoral approach. Although curative resection was performed in 21 patients, the PPS metastasis was not removable in 1 patient owing to an invaded internal carotid artery at the skull base. Twelve and 6 patients had locoregional and distant recurrence, respectively. Of the 12 patients with locoregional recurrence, isolated locoregional recurrence in the PPS occurred in 1. Eight patients died of distant or locoregional recurrence, with a median survival time of 91.7 months. For patients who experience recurrence after thyroid surgery, the possibility of PPS metastasis should be considered. In this series, all patients with PPS metastasis also had previous unilateral or bilateral cervical metastasis. Despite curative attempt, most patients experienced local or distant recurrence.