Thyroid papillary carcinoma with an insular component metastasizing to the sella turcica and sphenoid sinus: Case report

INTRODUCTION: Papillary carcinoma accounts for approximately 80% of all thyroid carcinomas. It is associated with relatively good survival. Distant metastases occur in approximately 10% of the patients, with the lung and bone being the most commonly reported sites. We present a case of unusual metastasis to the sphenoid bone and sella turcica from papillary thyroid carcinoma with an insular component. CASE PRESENTATION: We present a case of 70 years old female patient who presents a voluminous goiter with an 11 cm mass of the left sixth rib. Trans-parietal biopsy proved its metastatic origin from a thyroid papillary carcinoma. The patient was treated with total thyroidectomy and radiation therapy as the metastatic tissue is radioiodine refractory. Pathology revealed a papillary carcinoma with an insular component. A year later, the patient develops another metastasis to the sphenoid bone extending to the sella turcica, cavernous sinus, and carotid arteries. Treatment was based on kinase inhibitor. DISCUSSION: Metastatic invasion of the skull develops in 2.5%–5.8% of differentiated thyroid carcinoma and mostly affects the sella turcica, pituitary gland, cavernous sinus and sphenoid sinus. The presence of an insular component in a well-differentiated thyroid carcinoma seems to be associated with a poor prognosis. For cases where the metastatic disease is found to be resistant to conventional therapies, some clinical trials show promise with the use of tyrosine kinase inhibitors such as Sorafenib. CONCLUSION: Management of such uncommon cases remains challenging and should take in consideration evidence based guidelines, prognostic factors, disease progression path and treatment morbidity.