Immunocytochemical staining with monoclonal antibody MoAb47 in the diagnosis of thyroid neoplasms (preliminary communication).

The study is aimed at the estimation of diagnostic value of immunocytochemical (ICH) staining with MoAb47 of cytological material from thyroid nodules obtained by FNAB with emphasis on a precise distinction between benign and malignant follicular tumours. Monoclonal antibody 47 has very strong avidity to thyroperoxidase (TPO) from normal thyrocytes and from benign thyroid lesions. Binding of MoAb47 with TPO from thyroid carcinoma cells is null or very weak. We report the results of ICH staining in 34 cases of "cold" or quickly growing thyroid nodules, most of them solitary. Cytological diagnosis was thyroid carcinoma in 4 cases, microfollicular neoplasm in 7 and different benign lesions in 23. As expected in carcinomas the ICH staining was negative and the presence of cancer was histopathologically proved in 3 already operated on patients. In all follicular tumours staining with MoAb47 was positive and in 5 surgically treated cases postoperative examination identified benign follicular adenoma. Smears from colloidal nodules, cystic and degenerative lesions stained positively with MoAb47. In our opinion staining of cytological material with MoAb47 may improve the diagnosis of thyroid nodules.