Percutaneous endoscopic gastrostomy site metastases in head and neck cancer: use of FDG PET-CT.

PURPOSE To retrospectively evaluate the utility of positron emission tomography-computed tomography (PETCT) in the diagnosis of percutaneous endoscopic gastroscopy (PEG) site metastases in head and neck cancer. MATERIALS AND METHODS From the database of 250 patients of head and neck cancer who were referred for PET-CT over 2 years (from January 2005 to January 2007), 6 patients who had PEG tube placement were considered for the study. Imaging was performed on a GE Discovery ST PET-CT system after intravenous injection of 370 MBq (10 mCi) of < sup > 18 < /sup > F-fluorodeoxyglucose (FDG). RESULTS Intense FDG uptake with an associated soft tissue mass was seen at the PEG site in 3 patients and mild uptake was seen in 2 patients. Biopsy revealed PEG site metastases in 2 patients, abscess in 1 patient, and granulation tissue in 1 patient. Intense uptake with an associated soft tissue mass suggested the diagnosis of metastasis. Stranding of the peristomal fat seen on the CT component of the PET-CT indicated an infective/inflammatory pathology. PET-CT findings showed local recurrence in 3 patients and disseminated metastases (excluding the PEG site) in 1 patient. CONCLUSION The functional information provided by PET combined with the morphologic detail of CT can improve characterizing of the stoma site abnormality and help in distinguishing recurrence from infective/inflammatory changes. Whole body combined PET-CT is a useful modality for evaluating gastrostomy site metastases and for detecting coexisting local recurrences and distant metastases in head and neck cancer patients. In addition it can detect early asymptomatic recurrences at the gastrostomy site.