True vocal fold immobility in the setting of well-differentiated thyroid carcinoma: unusual illustrative cases and recommendations for operative strategy.

Objectives: We present cases of transient true vocal fold (TVF) immobility caused by well-differentiated thyroid carcinoma (WDTC), and review the literature concerning management of WDTC invading the recurrent laryngeal nerve (RLN).

Methods: A description of the clinical course of 2 patients with WDTC and transient TVF immobility is presented in the context of a review of the literature concerning locally advanced WDTC with extrathyroidal extension and RLN involvement.

Results: Both patients had papillary thyroid carcinoma with ipsilateral TVF paralysis that resolved completely before operation. During the operation, the RLN was found to be grossly involved with disease and inseparable from the tumor, necessitating resection. Review of the literature revealed the following points that should be considered when confronting an RLN invaded by WDTC. (1) Benign disease can mimic invasive WDTC and must be ruled out. (2) RLN invasion does not carry the same prognostic implications as other categories of extrathyroidal extension of WDTC. (3) RLN sacrifice does not increase the overall survival rate. (4) There is no evidence that a paralyzed RLN will regain function when preserved. (5) The majority of RLNs that function before operation can be expected to function after the operation if preserved.

Conclusions: Resolution of TVF paralysis should not reduce suspicion of RLN involvement by WDTC. When RLN involvement is discovered during operation, every attempt should be made to preserve a functioning RLN.