Choroid plexus metastases from thyroid carcinoma are very rare, with only few cases reported thus far.
The first reported patient with an isolated Hurthle cell papillary thyroid carcinoma metastasis to the choroid plexus of the lateral ventricle. Unresponsive to iodine ablation and refusing surgery, the patient underwent Gamma Knife radiosurgery (Elekta AB, Stockholm, Sweden), receiving 15Gy to the 50% isodose line. The lesion regressed until 5 years later at which time it was unresponsive to 18Gy and required surgical resection. Although extraneural metastatic cancers are recognized as potential sources for the single choroid plexus mass, we must consider even the unusual culprit in patients with a history of cancer 1).
A 52-year-old woman with a history of PTC who presented with severe headache, nausea and vomiting, right hemiparesis, and speech disturbance. Imaging studies depicted lesions in both lateral ventricles.
The patient underwent microsurgical tumor resection. Histopathologic examination revealed choroid plexus metastasis from PTC.
Metastases to the choroid plexus from extracranial tumors are very rare, with only a few cases reported thus far. A demographic analysis of these cases suggests there may be a tropism of some extracranial carcinomas, such as renal cell carcinoma, for choroid plexus, especially in the lateral ventricles. Sharifi et al. reported the eighth case of choroid plexus metastasis, but it is the first bilateral one arising from thyroid cancer 2).
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 3).
Healy et al. reported the first patient with an isolated Hurthle cell papillary thyroid carcinoma metastasis to the choroid plexus of the lateral ventricle. Unresponsive to iodine ablation and refusing surgery, the patient underwent Gamma Knife radiosurgery (Elekta AB, Stockholm, Sweden), receiving 15Gy to the 50% isodose line. The lesion regressed until 5years later at which time it was unresponsive to 18Gy and required surgical resection. Although extraneural metastatic cancers are recognized as potential sources for the single choroid plexus mass, we must consider even the unusual culprit in patients with a history of cancer 4)
A 74-year-old woman with magnetic resonance imaging (MRI) demonstrating a 4 cm round, heterogeneously enhancing mass in the trigone of the right lateral ventricle. Systemic screening by computed tomography (CT) examination detected a 20 mm nodule with calcification in the thyroid, multiple well-circumscribed nodules in bilateral lung filed, and a bone metastasis to the right dorsal rib. Cerebral angiography demonstrated a hypervascular mass fed from anterior and posterior choroidal arteries. Tumor biopsy via the parietal transcortical approach confirmed a thyroid carcinoma metastasis to the choroid plexus. Of the 33 reported cases of choroid plexus metastasis, 14 (42%) are from kidney and 3 (9%) from thyroid cancer, which appears to be overrepresented considering their prevalence among all brain metastasis. There may be a seed-and-soil relationship between thyroid cancer and choroid plexus 5).
Wasita et al. reported a 75-year-old man presented with severe headache, nausea, and vomiting. He had a history of thyroid carcinoma, which had metastasized to the lymph nodes and lung. Computed tomography, magnetic resonance imaging, and magnetic resonance angiography revealed right intraventricular hemorrhage with mild hydrocephalus, without evidence of a bleeding source. The bleeding source was assumed to be the choroid plexus metastasis in the trigone of the right lateral ventricle (following second admission).
Surgery was performed using a navigation-assisted system. The tumor was entirely removed, including some choroid plexus tissue. A ventriculoperitoneal shunt was also performed to treat the hydrocephalus. Histopathological examination revealed brain metastasis from papillary thyroid carcinoma. Postoperatively, the patient showed good recovery, with nausea and vomiting improved, and gait disturbance diminished. The patient was discharged from the hospital one month later.
Choroid plexus metastasis from papillary thyroid carcinoma is very rare, and this is the first case of intraventricular hemorrhage reported 6).