Coexistence of papillary thyroid carcinoma with metastatic fallopian tube carcinoma identified in neck dissection: A case report

We present a case of coexistence of papillary thyroid carcinoma (PTC) and metastatic fallopian tube carcinoma within cervical lymph nodes. A 63-year-old female with a history of fallopian tube cancer presented with rising CA-125 levels and hypermetabolic cervical nodes. While fine-needle aspiration of the thyroid gland suggested PTC, a total thyroidectomy with central neck dissection revealed incidental bilateral PTC (pT1a) alongside unexpected central nodal metastasis from high-grade serous carcinoma. This diagnosis was confirmed via immunohistochemistry (WT-1+/p53+/TTF-1−). Following subsequent lateral neck dissection for recurrence and salvage chemotherapy, the patient achieved complete remission. This case underscores that cervical lymphadenopathy in patients with prior extra-thyroidal malignancy should not be presumed to be of thyroid origin. It highlights the critical diagnostic role of lymph node sampling and immunohistochemical differentiation in guiding definitive oncological management.