Asymptomatic Isolated Vulvar Metastasis in Old Treated Case of Carcinoma Rectum-Diagnosis and Treatment Response Evaluation by 18F-FDG PET/CT Scan.

We report a clinically asymptomatic, old treated case of carcinoma rectum, presenting with raised serum carcinoembryonic antigen level, referred for F-FDG PET/CT scan for restaging. Whole-body PET/CT scan revealed an isolated FDG-avid lesion in the left labia majora region, which on histopathology was found to be metastasis from carcinoma rectum. Subsequent F-FDG PET/CT done after 4 cycles of chemotherapy revealed favorable response to therapy. F-FDG PET/CT facilitates the detection of unusual site of metastasis and its subsequent response evaluation in the index case.