Case report: Positron emission tomography fails to detect pulmonary adenocarcinoma recurrence after radiofrequency ablation.

We describe the case of late recurrence of a focus of invasive mucinous adenocarcinoma (formerly mucinous bronchioloalveolar carcinoma) following radiofrequency ablation, despite a negative positron emission tomography/computed tomography scan at 13 months following the ablation. A computed tomography scan performed at 24 months demonstrated unequivocal recurrence of the lesion. Combined positron emission tomography/computed tomography has been described as an adequate modality for the follow-up of thermally ablated pulmonary lesions. However, its utility in the follow-up of well-differentiated pulmonary adenocarcinoma may be limited. Lesion activity may be underestimated by an inherently low metabolic activity. Small lesions may also be susceptible to partial volume effect. Long-term imaging follow-up of well-differentiated pulmonary adenocarcinoma beyond two years after thermal ablation is prudent to avoid missing late recurrence.