Valore della immunocitochimica nella diagnosi di masse laterocervicali in pazienti con pregresso carcinoma della tiroide.

BACKGROUND: The aim of this study is to evaluate the additional diagnostic significance of immunocytochemical staining of thyreoglobulin (TG) in Fine Needle Aspiration Biopsy (FNAB) of neck lymph-nodes, in patients with a previous history of thyroid carcinoma. METHODS: Twenty-five smears performed by ultrasound-guided FNAB on laterocervical nodes with a 21-23 gauge needle were evaluates. All smears were stained according to Papanicolaou and microscopically examined. RESULTS: Of these 25 smears, 15 were diagnostic and 10 were non diagnostic. Of the 15 diagnostic cases, 10 were positive for metastatic lesions from thyroid neoplasm and the other 4 were classified as reactive lymphoadenitis. One smear for each case was selected for the immunohistochemical stain. All the 10 non-diagnostic cases showed no reaction to thyreoglobulin. Neoplastic cells, from 9 out of 11 cytologically positive smears, expressed thyreoglobulin in the cytoplasm. In one case no reaction was evident and the other one was discarded for technical reasons. In 3 of the 4 cases cytologically classified as lymphoadenitis, immunoreactive thyreoglobulin was not found. In the fourth case, blastic-like cells showed a scanty cytoplasmic rime which was immunoreactive for TG and thus was classified as a metastatic tumour. On this basis, it is suggested that FNAB should be performed routinelly in the diagnostic evaluation of neck masses of unknown origin in patients with a previous history of thyroid neoplasm. CONCLUSIONS: If the FNAB is inconclusive, a second aspiration should be performed while immunoperoxidase stain to evidentiate TG may be an adjuntive diagnostic tool in cytologically negative cases.