Management considerations for differentiated thyroid carcinoma presenting as a metastasis to the skull base

Objectives/Hypothesis: To characterize the salient features of skull base metastasis from differentiated thyroid carcinoma, discuss the diagnostic and treatment strategies, and propose rational management guidelines for such tumors. Study Design: Case report. Methods: Review of English literature from MEDLINE with the addition of our case. Results: Skull base metastasis from differentiated thyroid carcinoma is rare, with only 20 cases reported to date, including our case report. On the basis of a review of all reported cases, both follicular and papillary thyroid cancers can metastasize to the skull base. Our case is unique because the lesion extends locally into the cavernous sinus and beyond. Histopathologic diagnosis is limited by the remote location of lesions. Most tumors are highly vascular, and there is potential for significant morbidity and mortality associated with surgical resection. The overall survival ranges from less than one year to 10+ years from the discovery of the metastasis and is similar in both tumor subtypes. There is no clear consensus on the management strategy for skull base metastasis from differentiated thyroid carcinoma. Interestingly, surgical resection of both the primary and metastatic lesions yields similar survival when compared with resection of the primary tumor alone. Conclusions: Distant metastasis from differentiated thyroid carcinoma needs to be considered in the differential diagnosis of destructive skull base lesions, regardless of the patient's age. Histopathologic tissue diagnosis should always be attempted, followed by total thyroidectomy, radioiodine, or external beam radiation, and chronic thyroid-stimulating hormone suppression. Surgical resection of the metastatic lesion should only be performed in carefully selected cases because it is associated with significant morbidity.