Overcoming Diagnostic Limitations: A Case of Metastatic Renal Cell Carcinoma with Negative PET CT Findings

Abstract

Clear cell Renal cell carcinoma is the most common solid tumor of the kidneys. Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) imaging is limited in RCC due to the physiological excretion of FDG by the kidneys, which can obscure renal lesions. However, PET/CT has been shown to be reliable for detecting metastatic lesions in other regions. 74-year-old male, post left nephrectomy for renal cell carcinoma, presented with new bilateral pulmonary nodules on CT imaging. PET/CT scan showed no increased FDG uptake in the lung nodules (largest1.3cm). Despite this, given the high clinical suspicion for metastasis, a CT-guided biopsy of the left lower lung lobe was performed, revealing clear-cell carcinoma consistent with metastases from RCC. After chemotherapy, follow-up CT scans showed improvement in nodules. Despite negative PET, high clinical suspicion, driven by the patient’s history and CT, led to timely diagnosis and treatment. This underscores the importance of clinical in oncologic management.