Poorly Differentiated Lung Carcinoma Presenting with Intraspinal Extension and Symptoms of Secondary Neurogenic Bladder: [18F]F-FDG-PET/CT documentation

Abstract [18F]FDG-PET/CT (18F-fluorodeoxyglucose positron emission tomography/computed tomography) plays a crucial role in comprehensive oncologic staging and management of lung carcinoma. Although vertebral involvement is common in advanced malignancy, direct intraspinal extension with resultant neurological complications is uncommon but a clinically significant entity and may necessitate urgent intervention. We present a case of biopsy-proven poorly differentiated lung carcinoma in a 74-year-old male in whom [18F]FDG-PET/CT demonstrated an intensely FDG-avid paraspinal lung mass with chest wall invasion, vertebral destruction, and intraspinal extension causing spinal cord compression. The study additionally revealed a markedly distended urinary bladder consistent with the patient's clinical symptoms of neurogenic bladder secondary to spinal involvement, along with an associated large pneumothorax. This case highlights the value of [18F]FDG-PET/CT in comprehensive disease assessment and in detecting life-threatening neurological complications beyond routine staging. An FDG-avid psoas collection raised the possibility of an infective/inflammatory mimic, emphasizing interpretive pitfalls of FDG uptake in infection and inflammation.