Cerebellopontine angle metastasis from papillary carcinoma of the thyroid: case report and literature review.

BACKGROUND

Papillary thyroid carcinoma is the most common type of well-differentiated thyroid malignancy and typically has an excellent prognosis and a low incidence of distant metastasis. However, once metastasis has developed in a distant site, prognosis is markedly diminished. Brain metastases from papillary thyroid carcinoma are extremely rare. Currently, there are no established therapeutic guidelines for treating brain metastases from thyroid carcinoma.

CASE DESCRIPTION: We report on the case of a patient who presented with worsening neurological symptoms 3 years after resection of a thyroid papillary carcinoma. Magnetic resonance imaging identified a lesion of the cerebellopontine angle that encased the lower cranial nerves. The patient underwent a left retrosigmoid craniotomy with a 98% resection of the mass and received postoperative adjuvant radioiodine therapy, external beam radiation, and Gamma Knife radiosurgery. The patient tolerated the procedure well and demonstrated significant progressive improvement in her neurological symptoms postoperatively. After the multimodal approach to therapy, she remains symptom-free at 3-year follow-up. Radiographic monitoring of the small tumor remnant reveals a decrease in size from the postoperative period.

CONCLUSION

This article is the first formal case report of cerebellopontine angle metastasis from papillary thyroid carcinoma. Therapeutic protocols for brain metastases of papillary thyroid carcinoma are not firmly established. This case illustrates the unique event of a cerebellopontine angle metastasis from papillary thyroid carcinoma, which was successfully treated with a combination of surgical, chemical, and radiological modalities. This aggressive course of therapy has resulted in an excellent outcome in this instance.