Brain metastasis from differentiated thyroid carcinoma responding to radioiodine therapy

TL;DR

A rare case of brain metastasis from thyroid cancer responded well to radioactive iodine therapy without serious side effects.

Contribution

This case suggests small, asymptomatic brain metastases with iodine uptake may be effectively treated with RAIT.

Findings

A brain metastasis from DTC responded to I-131 therapy with no severe adverse effects.

The brain lesion was small, asymptomatic, and detected via post-therapy I-131 scintigraphy.

A few case reports support RAIT as a viable option for select brain metastases.

Abstract

Brain metastasis (BM) occurs only in about 1% of differentiated thyroid carcinoma (DTC) cases. Although DTC generally has a good prognosis, once BM develops, the mortality rate significantly increases up to 78%. BM is usually treated by surgical resection or external radiotherapy, whereas radioactive iodine therapy (RAIT) using I-131 is much less often chosen because BM often shows poor uptake of I-131. In addition, even in case I-131 accumulates in the BM, RAIT could cause adverse effects such as brain hemorrhage and cerebral edema.

We present a case of BM from DTC that showed response to I-131 therapy with no severe adverse effects. The brain lesion was very small and asymptomatic, and was only found after a post-therapy I-131 scintigraphy. There are a few case reports where BM was cured by RAIT with little to no side effects. We theorize that BM that is small in size, asymptomatic and show I-131 accumulation could be successfully treated with RAIT.

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