Recurrent laryngeal nerve and voice preservation: routine identification and appropriate assessment - two important steps in thyroid surgery.

INTRODUCTION: The aims of this study were to assess and compare vocal cord functions before and after thyroid surgery after intra-operative identification of recurrent laryngeal nerve. PATIENTS AND METHODS: Recurrent laryngeal nerve (RLN) is seen intra-operatively in all cases undergoing thyroid surgeries. Vocal cord functions including any voice change were evaluated by indirect laryngoscopy (I/L) and direct laryngoscopy (D/L) before and after surgery. RESULTS: Prospective study on 100 patients over 18 months with a total of 146 nerves at risk (NAR). Majority were women (n = 86) with mean age of 37.48 years (range, 13-60 years). RLN was seen in all patients and 19 patients complained of some change in quality of their voice after surgery. Evaluation by I/L and D/L at 6 weeks showed recurrent laryngeal nerve palsy (RLNP) in nine (47.36%) and five (26%) of these 19 patients respectively. Analysed according to total NAR, the incidence of voice change and temporary RLN palsy (I/L and D/L) at 6 weeks was still less at 13.01%, 6.16% and 3.42%, respectively. Voice change improved in all cases at 3 months with no RLNP palsy by I/L or D/L. All these 19 patients had undergone difficult or extensive surgery for malignancy, large gland, extratyhroidal spread or fibrosis. CONCLUSIONS: Despite identification and preservation of RLN, patients can develop postoperative voice change and RLNP although all voice change cannot be attributed to damaged RLN. Proper assessment of vocal cord functions by I/L and D/L laryngoscopy is required to rule out injuries to these nerves. Risk of damage is higher in patients undergoing more difficult surgery.

Absence of microfollicular basement membrane: a new indicator in the diagnosis of follicular carcinoma thyroid.

The thyroid follicles represent a biological continuum. Each follicle is closely related to the follicle that is next to it. The important feature of a follicular carcinoma is a microfollicular pattern. We report a case of follicular carcinoma in a 48-year-old female that demonstrates microfollicles which are larger in size and contain more number of follicular cells in cytologic smears (20-29 cells) in contrary to the literature definition of microfollicles containing approximately 6-12 cells. We also demonstrate absence of basement membranes in these microfollicles in histologic sections by Silver Methanamine Stain, which may be an indicator to search for vascular and capsular invasion. This case report also describes postoperative positron emission tomography scan findings.

Role of 99mTc-Tetrofosmin delayed scintigraphy and color Doppler sonography in characterization of solitary thyroid nodules.

OBJECTIVES: A study was undertaken to evaluate the diagnostic efficiency of Tc-Tetrofosmin scan and color Doppler in the characterization of benign and malignant solitary thyroid nodules. METHODS: Fifty-two patients found to have a cold solitary thyroid nodule on Tc-pertechnetate scintigraphy were included in this study. All patients underwent a single-injection dual-phase (30 min and 120 min) Tc-Tetrofosmin scan. The intranodular vascularity was measured using color Doppler sonography. Fine-needle aspiration cytology was performed on all the patients. In the following days and weeks all patients underwent surgery. RESULTS: Thirteen out of 15 patients with thyroid cancer showed delayed retention of radiotracer (on 120 min images as compared to the initial 30 min image). Thirty-six out of 37 patients harboring benign solitary nodules showed significant washout of tracer on delayed images. Sensitivity, specificity, positive predictive value and negative predictive value of delayed Tc-Tetrofosmin scintigraphy were found to be 86.6, 97.2, 92.8 and 94.7%, respectively. The Doppler study was able to demonstrate increased vascularity in the center of 8 of the 15 malignant nodules. Thirty-two patients harboring a benign solitary nodule showed normal or increased peripheral vascularity on Doppler study. Sensitivity, specificity, positive predictive value and negative predictive value of color Doppler were found to be 53.5, 86.4, 61.5 and 82%, respectively. CONCLUSION: Delayed Tc-Tetrofosmin scintigraphy is a highly sensitive and specific method for characterizing solitary thyroid nodules, while color Doppler has a low sensitivity but relatively high specificity in differentiating benign from malignant thyroid lesions.

Primary squamous-cell carcinoma of the thyroid gland: new evidence in support of follicular epithelial cell origin.

Primary squamous-cell carcinoma (SCC) of the thyroid gland is extremely rare. We had an opportunity to treat two such cases recently. Two elderly females presented with left lobe thyroid swelling that had a history of long-standing goiter. Fine-needle aspiration (FNA) of the thyroid nodule was done in both cases. FNA cytology showed an thyroid abscess in the first, and a Hürthle-cell neoplasm in the second case. Histopathologic diagnosis was a well-differentiated squamous-cell carcinoma with an adjacent area of lymphocytic thyroiditis in the first case, and a moderately differentiated squamous-cell carcinoma in association with a Hürthle-cell adenoma in the second case. Serial sections of the excised gland ruled out any other associated thyroid malignancy. Immunostaining for pan-cytokeratin, thyroglobulin, and calcitonin were performed. The tumor, comprising polygonal and spindle cells, showed positive staining for cytokeratin and thyroglobulin; however, calcitonin did not stain any structures. Exhaustive clinical, endoscopic, and radiological examinations, i.e., X-ray of the chest, contrast-enhanced computer tomography (CECT) of the neck and chest, and ENT checkup in both cases did not reveal any primary site of squamous-cell carcinoma as the likely source of the metastases, or any contiguous spread from neighboring structures. Both patients had ipsilateral nodal metastases, and both succumbed to the disease within 6 mo of histological diagnosis. The interesting observation in both cases was thyroglobulin positivity, indicating a follicular epithelial cell origin of the SCC.