Background: In the follow-up of patients with a history of thyroid carcinoma, an enlarged cervical lymph node may indicate metastatasis is underway. Various methods may be utilized in the differential diagnosis between cancer metastasis of thyroid origin and aspecific lymphoadenitis. The aim of the present study was to evaluate the sensitivity and specificity of fine needle aspiration biopsy (FNAB) and the additional diagnostic value of immunocytochemical thyroglobulin staining on FNAB of neck nodes.
Methods: We evaluated cytologically 38 samples obtained by ultrasound-guided FNAB on laterocervical nodes from patients with a history of thyroid carcinoma. One smear for each case was selected for the immunocytochemical stain.
Results: Twenty-eight of those samples were adequate (16 positive for metastasis of thyroid origin and 12 negative) and 10 inadequate. Two of the cytologically positive samples from poorly differentiated neoplasia showed no reaction to thyroglobulin (Tg). In ten of the 11 cases classified as lymphoadenitis, no immunoreaction was present; in the last case, blastic-like cells showed a scanty cytoplasmic rim which was immunoreractive to Tg. Therefore, this case was reclassified as a metastatic tumor.
Conclusions: Based on our results, we would recommend that FNAB be routinely performed in the diagnostic evaluation of neck masses. If the FNAB is inconclusive, aspiration should be repeated, while immunoperoxidase stain to evidence Tg, may be an adjunctive diagnostic tool in cytologically negative cases.