[Metastases of a medullary carcinoma of the thyroid (follicular variant). Diagnosis and therapy using radioiodine].

Six years after surgery and radioiodine treatment of a medullary thyroid carcinoma a woman patient developed pulmonary metastases with radioiodine uptake. These were treated with 11.7 GBq (twice 150 mCi) 131I. Retrospective immunohistochemistry of the primary tumour revealed a mixed medullary and follicular pattern. Since it is likely that in patients having such follicular variants of medullary thyroid carcinoma the metastases are of a similar pattern, immunohistochemistry should aim at identifying follicular structure, followed by initiation of whole body scintigraphy and radioiodine treatment if appropriate.