Bladder Crystal Formation shown as false positive cause in F-18 Fluorodeoxyglucose (FDG) Positron Emission Tomography/Computed Tomography (PET/CT)

Abstract

Introduction: There are some false positivity reasons for the bladder in FDG PET/CT. This case report demonstrates one of these causes which were not reported before.

Case and outcomes: A male patient sixty-five years of age with known diagnosis of metastatic colon carcinoma receiving chemotherapy treatment referred for follow up FDG PET/CT which showed partial metabolic response and suspicious calcified lesion in the bladder wall with significant FDG accumulation. Cystoscopy and pathology results demonstrated crystal formation and adjacent inflammation as an explanation.

Discussion: The FDG accumulations due to foreign materials have been reported in elsewhere in the body before in the literature. This accumulation in this case may represent foreign body reaction.

Conclusion: This case report showed an interesting false positive lesion demonstrated firstly in the literature as far as we know. The follow up results confirmed that the FDG accumulation in the bladder was a false positive.