Introduction
Thyroid cancer is among the most commonly diagnosed cancers worldwide,
and the incidence is increasing1. Differentiated
thyroid cancers (DTC) account for most of these cases, of which PTC is
the most common subtype with favourable 10-year survival of up to
90-95%1,2. PTC most commonly presents as an
asymptomatic thyroid mass or nodule and less commonly with regional or
distant metastasis at onset of diagnosis. Up to 20-50% of PTC will
involve cervical lymphatic spread and 1-4% involve distant metastasis,
with 5 year survival rates reduced to 28% for single-organ and 11% for
multi-organ metastasis3. The majority of patients with
metastatic disease have single-organ metastasis, most commonly lung
(53%), bone (28%), liver (8%) and brain (5%)3. We
present a case of an isolated cerebellar lesion as the presenting
feature of metastatic PTC with other unusual features, including an
incidental finding of microMTC (medullary thyroid microcarcinoma).