Recurrence of lung cancer after radiofrequency ablation detected by PET/CT and contrast enhanced CT scan.

mediciNe & HealtH/RHode islaNd 82-year-old feMale wiTh a hisTory of cough for three months had a CT of the chest which revealed a 1.5 cm right upper lobe pulmonary nodule. (Figure 1) The patient underwent a CT guided percutaneous biopsy which on histology was consistent with adenocarcinoma of the lung. The patient then underwent a positron emission tomography/computed tomography (PET/CT) scan (Figure 2) with 18F-fluorodeoxyglucose (F-18 FDG) for staging which showed intense uptake in the right upper lobe adenocarcinoma without evidence of metastatic disease. The patient was not a surgical candidate due to poor pulmonary reserve and subsequently underwent percutaneous radiofrequency ablation (RFA) of the right upper lobe adenocarcinoma. After RFA, a follow-up PET/CT (Figure 3) six months later showed curvilinear activity around the ablation site with slightly more intense activity anteriorly. A contrastenhanced CT scan (Figure 4) showed focal enhancement in the anterior aspect of the ablation cavity corresponding to the area of more focal intense activity seen on the follow-up PET/CT. Percutaneous CT guided biopsy of this region confirmed suspicion of residual or recurrent adenocarcinoma. The patient was retreated with RFA. (Figure 5) Repeat CT scan (Figure 6) performed at four months after reablation showed no evidence of residual tumor (not shown).