Metastasis Of Thyroid Cancer with No Primary Focus Seen: A Case Report

Objective: Differentiated thyroid carcinoma (DTC), encompassing papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC), represents the predominant histological subtype of thyroid malignancies.While distant metastases in DTC occur less frequently compared to other solid tumors, with pulmonary and osseous involvement being the most common sites of dissemination, renal metastases as the initial clinical presentation remain uncommon.Notably, synchronous metastatic involvement of multiple rare anatomical locations in DTC constitutes an exceptionally rare clinical scenario.Subject and Methods: A 56-year-old Asian male presented with a one-month history of persistent lumbar discomfort.Computed tomography (CT) imaging revealed a hypodense mass in the right renal parenchyma, accompanied by concurrent metastatic lesions in bilateral pulmonary fields and multiple osteolytic rib lesions.Subsequent diagnostic evaluation established the provisional diagnosis of primary renal cell carcinoma with synchronous pulmonary metastases and skeletal metastases.Results: The patient was diagnosed with metastatic differentiated thyroid carcinoma demonstrating multiorgan dissemination, presenting with synchronous renal, hepatic, cerebral, and cutaneous metastases.A multidisciplinary therapeutic regimen was implemented, comprising total thyroidectomy with bilateral recurrent laryngeal nerve monitoring, laparoscopic radical nephrectomy of the right kidney, followed by two cycles of adjuvant radioiodine therapy (131I) combined with levothyroxine-mediated thyroid-stimulating hormone (TSH) suppression therapy. Conclusion:The management of DTC patients presenting with synchronous multiorgan metastases as initial manifestations requires a meticulously coordinated therapeutic paradigm.This clinical scenario necessitates mandatory multidisciplinary tumor board (MTB) review to formulate risk-adapted treatment algorithms, integrating systemic therapeutic modalities with metastasis-directed local interventions based on comprehensive molecular profiling and precise assessment of disease burden.