Carcinoma, tuberculosis and elastofibroma in one patient: is [18F]FDG-PET/CT helpful?

We present the case of a woman with persistent dorsal pain and two solid lung lesions documented on multidetector CT which showed concomitant [18F]FDG uptake. One of the lesions proved to be adenocarcinoma at biopsy and presented a lower [18F]FDG uptake when compared to the second lesion, which was smaller in size, and was postsurgically diagnosed as tuberculoma. This case portrays the paradoxical metabolic behaviour of two lesions, leading to misdiagnosis and erroneous disease staging in an oncology patient. Incidentally, the patient also had an elastofibroma dorsi, a rare benign tumour which can also be a possible source of false results in the PET exam. We provide explanations and possible solutions to these findings in order to familiarise the physician with them, and optimise patient management.