Objective: To investigate the incidence of lateral neck node occult metastasis and to show the usefulness of sentinel lymph node biopsy (SLNB) in the detection of lateral neck node metastasis in thyroid carcinoma, the investigators used a radioisotope to detect the sentinel lymph node.

Summary Background Data: Although occult lymph node metastasis to the lateral neck compartment is common in papillary thyroid carcinoma, the incidence and patterns of lateral neck node metastasis in papillary carcinoma are not known.

On the day of the operation, patients underwent preoperative lymphoscintigraphy after the intratumoral injection of a Tc-99m phytate 1 mCi in 0.1-0.2 mL 0.9% NaCl under ultrasonographic guidance. Total thyroidectomy or lobectomy with central neck dissection preceded SLN detection to avoid interference by primary tumor radioactivity. After total thyroidectomy or lobectomy, the dissections were performed toward the internal jugular chain beneath the sternocleidomastoid muscle. A handheld, collimated gamma probe and lymphoscintigraphy were used to scan the lateral compartments (through skin and under the SCM) for "radioactive" lymph nodes. Removed SLNs were submitted immediately for frozen biopsy. If any of the SLNs were positive for metastasis on the frozen sections, MRND was performed immediately. In cases for which the frozen section was negative but the final pathology report detailed microscopic positivity in the lateral sentinel nodes, RAI ablations were performed without additional MRND.

Inclusion Criteria:

• Cases with tumors larger than 1 cm in size or with suspicious central neck node metastasis in Papillary thyroid cancer

Exclusion Criteria:

• The patient with definite metastatic lymph node in lateral neck compartment