Abstract
Lung cancer with peritoneal carcinomatosis (PC) is a rare disease presentation. The presence of peritoneal disease is a sign of poor prognosis and is hard to diagnose. Flourine-18 fluorodeoxyglucose positron emission tomography/computed tomography ( (18) F-FDG PET/CT) is becoming more clinically significant in the management of patients with PC. A 60-year-old male presented with nonsmall cell lung cancer (NSCLC) and later showed signs of peritoneal disease on (18) F-FDG PET/CT imaging, which subsequently lead to the diagnoses of PC with histopathology from peritoneal biopsy. The patient showed an excellent initial response to their NSCLC treatment but later presented with PC that was shown by FDG-avid ascites and a soft tissue mass in the pelvic area. The abdominal-pelvic lesions were confirmed cytologically to be peritoneal metastatic disease. (18) F-FDG PET/CT demonstrated value in preoperatively directing biopsy for diagnosing PC in this case of NSCLC. Further, (18) F-FDG PET/CT was useful in the monitoring of disease progression and thus influenced management in this case of NSCLC with PC, which is often challenging to detect and manage.