Skull Metastasis Extending to the Superior Sagittal Sinus: An Unfamiliar Presentation of Papillary Thyroid Carcinoma

Thyroid cancer is the most common endocrine cancer in the world, with a rising global incidence over the last three decades. Papillary thyroid cancer (PTC) is the most common type of thyroid neoplasia, accounting for 74%-80% of all cases. Skull metastasis from a differentiated thyroid malignancy is a rare occurrence, while a subsequent dural involvement is even more inimitable. As such, a clinician requires a high degree of clinical suspicion and resultant radiographic evidence in order to make the diagnosis. Here we present the case of a 54-year-old male patient who presented with a pathological fracture of his right humerus, a midline frontal bone swelling and an asymptomatic neck mass. Further workup revealed follicular variant papillary thyroid carcinoma (FV-PTC) with distant metastasis to the calvarium. The conventional therapy for metastatic PTC includes a total thyroidectomy, removal of resectable metastatic lesions and a supplementation with radioactive iodine (RAI) and/or external beam radiation at the sites of the metastases. This case and our literature review illustrate that skull metastases should be considered in the clinical course of PTC so that appropriate management can be started.