Usefulness of immunohistochemistry in the diagnosis of nodular thyroid disease

Nodular thyroid disease (NTD) is represented by palpable thyroid nodules (solitary, multiple) and thyroid incidentalomas (identified by means of thyroid ultrasonography). The discussed entities carry the same risk of malignancy (about 5 %). The main objective in evaluating NTD is represented by the exclusion of malignancy by means of corroborated investigations, focused on the value of a panel of IHC markers. Material and methods. We included in the study 27 cases of NTD, evaluated by means of: clinical investigation, ultrasonography of the thyroid, cytological examination, morphological analysis and IHC. The used panel of IHC markers comprised: Ki-67, PCNA, CK 19 and c-erbB2 (DAKO LSAB method) Results. From the total of cases, 8 presented positivity with Ki-67 and 17 with PCNA. Regarding CK 19, the majority of PTC cases stained ++ and diffusely, but not papillary hyperplasia (focal positivity).c-erbB2 diffuse and intense positivity (+++) was noticed in PTC.The case with a follicular tumor of uncertain malignant potential stained weakly only with c-erbB2. Conclusions. From the used panel of IHC markers, CK 19 presented the best value, being able to differentiate FVPTC from FTC and PTC from papillary hyperplasia.