Sentinel node radioguided biopsy in surgical management of the medullary thyroid carcinoma A case report.

INTRODUCTION: Medullary thyroid cancer is a rare carcinoma. Surgery is the only curative treatment and since cervical lymphnodes metastases are frequent and can occur at an early stage, a standardized central lymphnode dissection is associated to total thyroidectomy. However, the extent of lymphadenectomy to the lateral neck lynphnodes remains debated. To reduce the extent of lymphnode excision, the sentinel node biopsy has been used as an accurate technique to assess the status of the lymphnodes in the regional drainage basin in solid tumors, and more recently, in thyroid carcinoma. In this case report, we show the utility of the radioguided biopsy of the sentinel lymphnode in the surgical management of the medullary thyrod cancer.

CASE REPORT: We present the case of a 24-year-old Caucasian, Italian woman with a sporadic medullary thyroid microcarcinoma occasionally detected by neck ultrasound and diagnosed by high serum calcitonin level and fine needle aspiration cytology. There was no ultrasound evidence of lymphnode involvement both in central and lateral compartment of the neck. We performed a preoperative mapping of the the sentinel lymphnodes by the injection of technetium-99m radiolabelled albumin nanocolloids in the thyroid nodule. Then our patient underwent total thyroidectomy combined with radioguided biopsy of the sentinel lymphnodes. Histology confirmed the presence of the medullary thyroid cancer and revealed micrometastases only in two sentinel lymphnodes detected in right lateral compartment of the neck so an ipsilateral lateral neck dissection besides the central neck dissection was performed at the end of operation. Basal and pentagastrin-stimulated serum calcitonin level was undetectable during the follow-up investigations.

CONCLUSION: This is the first reported case that shows the utility of the radioguided SLN biopsy for the accurate staging of the cervical lymphnode involvement in patient with sporadic medullary thyroid microcarcinoma. Total thyrodectomy and central neck dissection is recommended for all patients with medullary thyroid carcinoma, but the indication for the lateral neck dissection is still controversial. The radioguided SLN biopsy technique could be a useful tool to perform the dissection only in those patients with proven lateral neck lymphnode involvement and reduce the extention of the lateral lymphnode excision and the incidence of related complications.