Fluorescamine in cytodiagnosis of thyroid carcinomas

Fluorescamine, which reacts with primary amino groups yielding intensely fluorescent products, was found to induce intense fluorescence in cells from medullary and papillary thyroid carcinoma. No fluorescence was detected in cells from follicular or undifferentiated carcinoma or from benign thyroid lesions, except Hürthle cell adenomas, the cells of which exhibited moderate fluorescamine-induced fluorescence. This was demonstrated on fine needle aspiration biopsy smears pretreated with formaldehyde gas. Since the fluorescamine technique is simple and rapid, it may be of value as an aid in the cytodiagnosis of thyroid neoplasms.