Background: Papillary carcinoma is the most common differentiated malignant thyroid neoplasm. The biological course of this cancer is typically indolent with a protracted clinical course. Metastases commonly occur in regional lymph nodes, and distant metastasis is a late and rare occurrence. We report a patient who presented with cerebellar metastasis prior to the diagnosis of papillary thyroid carcinoma and review the literature of brain metastasis from papillary thyroid carcinoma.

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Introduction. Follicular thyroid carcinoma (FTC) frequently metastasizes to the lungs and bones. However, metastasis to the skeletal muscles is an extremely rare manifestation of FTC. To date, only seven cases of FTC have been reported in the literature. Skeletal muscle metastases from FTC usually remain asymptomatic or manifest as swelling and are associated with dismal prognosis. Case Presentation. A 45-year-old Saudi woman presented with right buttock swelling since 8 months. Physical examination revealed right gluteal mass of size 13 × 10 cm and right thyroid lobe nodule. The rest of examination was unremarkable. Magnetic resonance imaging (MRI) showed 13 × 11.7 × 6.8 cm lobulated mass arising from the gluteus medius muscle, and tru-cut biopsy confirmed the metastatic papillary carcinoma of thyroid origin. The patient subsequently underwent palliative radiotherapy followed by total thyroidectomy and radioactive iodine ablation. At the time of publication, the patient was alive with partial response in gluteal mass. Conclusion. Skeletal muscles metastases are a rare manifestation of FTC, and searching for the primary focus in a patient with skeletal muscle metastasis, thyroid cancer should be considered as differential diagnosis.