Preoperative scintigraphy with correlation to cytology and histopathology in carcinoma of the thyroid.

At preoperative scintigraphy of 83 consecutive histopathologically confirmed thyroid carcinomas a solitary reduced uptake was observed in 70 per cent. The minimum detectable size was 10 mm for differential carcinomas showing this image, but in the 'screening group' of hereditary medullary carcinoma several scintigrams were considered normal despite a tumour size of 10 to 15 mm. In the imaging of the undifferentiated carcinoma a solitary reduced uptake with disappearance of the entire affected lobe was often demonstrated. Multifocal areas in the dot scintigram representing tumours were often missed at fine needle aspiration biopsy. Computer-processed scintigrams were superior in showing multifocal lesions.