Scintigraphic studies in patients with medullary carcinoma of the thyroid.

Findings on pre-operative thyroid scintiscans in 29 patients with medullary carcinoma of the thyroid were compared with results of palpation and pathological findings. Six patients had a normal uptake of 131I or 99mTc in tumours 1.5--8 cm in diameter. When compared with 111 pre-operative scintiscans in other thyroid carcinomas, the frequency of normal uptake in medullary carcinomas was high, 19% versus 0--6%. Gallium-67 scintiscans were performed in nine patients. Six patients had extensive tumours, but accumulation of 67Ga appeared in only one patient.