Medullary Thyroid Carcinoma in Pregnancy: A Case Report and Literature Review on Maternal and Neonatal Outcome of Delayed Surgery Post-Partum

Abstract Thyroid malignancy poses a challenge especially when diagnosed during pregnancy. Although in papillary thyroid carcinoma, surgery can be safely delayed until the post-partum period, in medullary thyroid carcinoma, there is more urgency to treat. Here, we present a case of a 31-year-old female was diagnosed with medullary thyroid carcinoma during her third trimester. Diagnosis was made by aspiration cytology. Due to the patient’s condition, a CT scan was contraindicated and thus we were unable to make a complete assessment. A decision was made that the surgery was done after delivery, and when a complete assessment can be done. The surgery was successful and there were no complications both for the patient and her baby. In patients whom diagnosis of medullary thyroid carcinoma is made during the third trimester, it appears to be safe for mother and baby that surgery is done during the postpartum period. Keywords: Medullary thyroid carcinoma, MTC, thyroid carcinoma in pregnancy, MTC in pregnanc

The electrophysiology of thyroid surgery: electrophysiologic and muscular responses with stimulation of the vagus nerve, recurrent laryngeal nerve, and external branch of the superior laryngeal nerve

Objectives/Hypothesis: Correlation of physiologically important electromyographic (EMG) waveforms with demonstrable muscle activation is important for the reliable interpretation of evoked waveforms during intraoperative neural monitoring (IONM) of the vagus nerve, recurrent laryngeal nerve (RLN), and external branch of the superior laryngeal nerve (EBSLN) in thyroid surgery. Study Design: Retrospective chart review. Methods: Data were reviewed retrospectively for thyroid surgery patients with laryngeal nerve IONM from January to December, 2015. EMG responses to monopolar stimulation of the vagus/RLN and EBSLN were recorded in bilateral vocalis, cricothyroid (CTM), and strap muscles using endotracheal tube-based surface and intramuscular hook electrodes, respectively. Target muscles for vagal/RLN and EBSLN stimulation were the ipsilateral vocalis and CTM, respectively. All other recording channels were nontarget muscles. Results: Fifty surgical sides were identified in 37 subjects. All target muscle mean amplitudes were significantly higher than in nontarget muscles. With vagal/RLN stimulation, target ipsilateral vocalis mean amplitude was 1,095.7 \u3bcV (mean difference range = 12814.1 to 121,078 \u3bcV, P <.0001). For EBSLN stimulation, target ipsilateral CTM mean amplitude was 6,379.3 \u3bcV (mean difference range = 126,222.6 to 126,362.3 \u3bcV, P <.0001). Target muscle large-amplitude EMG responses correlated with meaningful visual or palpable muscular responses, whereas nontarget EMG responses showed no meaningful muscle activation. Conclusions: Target and nontarget laryngeal muscles are differentiated based on divergence of EMG response directly correlating with presence or absence of visual and palpable muscle activation. Low-amplitude EMG waveforms in nontarget muscles with neural stimulation can be explained by the concept of far-field artifactual waveforms and do not correspond to a true muscular response. The surgeon should be aware of these nonphysiologic waveforms when interpreting and applying IONM during thyroid surgery. Level of Evidence: 4 Laryngoscope, 127:764\u2013771, 2017