Thyroid follicular carcinoma presenting as skull and dural metastasis mimicking a meningioma: a case report

Follicular thyroid cancer rarely manifests itself as a distant metastatic lesion. We report a case of a 61-year-old woman presented with a solid mass located in the left temporo-occipital region. The 3D computed tomography showed a large solid mass with high vascularity, skull erosion and supra-infratentorial epidural mass effect. After magnetic resonance imaging (MRI) a suspect diagnosis of meningioma was made. The patient underwent surgery where a soft mass with transverse sinus invasion was encountered, the tumor was successfully resected employing microsurgical techniques. Histological examination revealed a thyroid follicular neoplasm with positive staining for follicular carcinoma in immunohistochemical analysis. Postoperatively levels of thyroid hormones were normal. Treatment was planned for the thyroid gland, but the patient did not consent. The present case emphasizes that although they are uncommon, dural metastasis can be mistaken for meningiomas. The definitive diagnosis of a meningioma should be established only after the histopathological analysis. Thyroid follicular carcinoma should be included in the differential diagnosis in cases of extrinsic tumoral lesions.