Detecting the sentinel lymph node in patients with differentiated thyroid carcinoma

The aim of this study was to evaluate sentinel lymph node mapping in patien ts with differentiated thyroid carcinoma. Nine patients with suspected thyr oid carcinoma who were scheduled to undergo thyroidectomy underwent scintig raphic localization of sentinel lymph nodes (SLNs). On the day of surgery w e injected 37 MBq technetium-99m nanocolloid intratumourally. Dynamic data up to 10 min followed by planar anterior and lateral oblique images up to 1 h after tracer administration were recorded. At surgery the primary tumour was excised first, then the SLNs were removed using a gamma probe. Four pa tients had papillary carcinoma, two follicular carcinoma, one an oncocytic tumour and two benign tumours. An SLN was identified in all four patients w ith papillary carcinoma. In the two patients with follicular carcinoma, SLN detection failed. Five patients had one radioactive node, one had three an d one had four. In one patient, no SLN was visible with scintigraphic imagi ng but at surgery three SLNs could be clearly identified using the gamma pr obe after removal of the primary tumour. There were no false-negative findi ngs. This initial study indicates that in patients with papillary thyroid c arcinoma detection of the SLN is possible, whereas the technique failed in two patients with follicular carcinoma. A study on a larger patient sample is now warranted.