PET/CT Imaging in Oncology: Exceptions That Prove the Rule

18F-FDG PET/CT is a diagnostic three-dimensional non-invasive device, routinely employed in neurology, cardiology, and oncology, and which contributes to patient care giving functional informations about glucose metabolism. In particular, staging, restaging, follow-up and response to treatment of tumors are the most common applications in oncologic field. Many neoplasms show increased glucose metabolism and consequent 18F-FDG uptake. Nevertheless, some relative differentiated cancers, such as clear cell carcinoma of the kidney and bronchioloalveolar adenocarcinoma, show tipically faintly/no uptake resulting in a consequent negative PET/CT scan. This case report represents an extreme case in which three relative well-differentiated cancer forms, all characterized by low glucose metabolism, affect the same patient at the same time while 18F-FDG PET/CT scan is negative.