Multifocal metastases to choroid plexus from papillary thyroid carcinoma: illustrative case.

Background: Choroid plexus metastases are extremely rare from all types of malignancy, with only 42 cases reported in the literature thus far. Most of these originate from renal cell carcinoma and present as a solitary choroid plexus lesion; only two cases of multifocal choroid plexus metastases have been reported to date.

Observations: The authors report the third case of multifocal metastases to the choroid plexus, that of a 75-year-old man who developed three measurable choroid plexus lesions approximately 3.5 years after undergoing total thyroidectomy and chemotherapy for papillary thyroid carcinoma. He underwent intraventricular biopsy of the largest lesion and subsequently died of hydrocephalus after opting for comfort care only.

Lessons: This is the third case of multifocal choroid plexus metastasis in the literature and the second case of multifocal metastasis from thyroid carcinoma. As such, the natural disease course is not well characterized. This case is compared with the previous eight reports of choroid plexus metastases from thyroid carcinoma, seven of which involved solitary lesions. The eight prior cases are evaluated with attention to treatment modalities used and factors potentially influencing prognosis, specifically those that might contribute to hydrocephalus, a reported complication for this pathology.