Barw Barw Medical Journal 2960-1959 2025 12 20 Unusual Metastasis from Follicular Thyroid Carcinoma: A Case Report and Literature Review 57 62 10.58742/bmj.v4i1.218 eng Abdulwahid M. Salih Department of Head & Neck Surgery, Smart Health Tower, Madam Mitterrand Street, Sulaymaniyah, Iraq. A.salih@smartglobalholding.co.uk Deari A. Ismaeil College of Medicine, Department of Clinical Sciences, University of Sulaimani, Madam Mitterrand Street, Sulaymaniyah, Iraq. deari.ismaeil@univsul.edu.iq Rawa M. Ali Department of Pathology, Hospital for the Treatment of Chemical Weapons Victims, Mawlawi Street, Halabja, Iraq. rawa.ali@gmail.com Ari M. Abdullah Department of Pathology, Sulaymaniyah Teaching Hospital, Zanko Street, Sulaymaniyah, Iraq. ariabdullah1978@gmail.com Karzan M. Salih Department of Head & Neck Surgery, Smart Health Tower, Madam Mitterrand Street, Sulaymaniyah, Iraq. karzan.salih@gmail.com Shko H. Hassan Department of Head & Neck Surgery, Smart Health Tower, Madam Mitterrand Street, Sulaymaniyah, Iraq. shkohamid81@gmail.com Twana Omer Saeed Department of Scientific Affairs, Smart Health Tower, Madam Mitterrand Street, Sulaymaniyah, Iraq. twanaomar25@gmail.com Ahmed H. Ahmed Department of Radiology, Smart Health Tower, Madam Mitterrand Street, Sulaymaniyah, Iraq. ahmed.ahmed@gmail.com Harun Amanj Ahmed Department of Thoracic and Vascular Surgery, Smart Health Tower, Madam Mitterrand Street, Sulaymaniyah, Iraq. Harun.amanj@gmail.com 2025 09 28 Introduction Follicular thyroid carcinoma (FTC) is a type of well-differentiated thyroid carcinoma. It has a poorer prognosis, is more metastatic, and has characteristics different from papillary thyroid carcinoma. It tends to metastasize hematogenously, usually to the bones and lungs. This study aims to present a rare case of FTC metastasis to the peritoneum and thigh of a patient with a literature review. Case presentation A 70-year-old patient presented with a right thigh mass. Magnetic resonance imaging of the right thigh revealed an intramedullary lesion in the femoral diaphysis. The thyroid gland was firm, with no evidence of enlargement. A computed tomography scan showed several peritoneal nodules. A core biopsy of the right upper femoral lesion and peritoneal mass was performed. Histopathologic findings and immunohistochemical analysis confirmed metastatic FTC with thyroid origin. Literature review Unlike widely invasive FTC, minimally invasive FTC has a better prognosis and is less metastatic. Imaging, histopathologic examination, and immunohistochemistry can help in arriving at a diagnosis of FTC. Mutations of PPAR-γ and RAS are associated with FTC. Radioiodine treatment and suppressive therapy for the thyroid-stimulating hormone have been shown to improve survival rates of FTC, with postoperative follow-ups and treatment being important. Conclusion Metastasis of FTC to the peritoneum is rare and could lead to a late diagnosis. Proper diagnosis with confirmatory tools such as immunohistochemistry and adequate treatment are critical.