Choroid Plexus Metastasis of Follicular Thyroid Carcinoma Diagnosed due to Intraventricular Hemorrhage.

Choroid plexus metastasis (CPM) is extremely rare and originates most frequently from renal cell carcinoma (RCC). We herein report the case of a 58-year-old man who developed a solitary CPM lesion derived from follicular thyroid carcinoma in addition to intraventricular hemorrhage. Computed tomography revealed acute hydrocephalus as a result of the hemorrhage, and we planned endoscopic hematoma evacuation. Since it was too difficult to reach the hematoma, we considered the possibility of a neoplasm and performed a biopsy of the lesion, the results of which led to an accurate diagnosis of CPM in this case. We also review previous reports of CPM originating from thyroid carcinoma compared with RCC.