Benign fibrous dysplasia on [¹¹C]choline PET: a potential mimicker of disease in patients with biochemical recurrence of prostate cancer

We present the case of a 74-year-old male with biochemical recurrence of prostate cancer who underwent [¹¹C]choline PET/CT. The PET/CT demonstrated an intense focus of uptake within the skull base that was initially felt to potentially represent metastatic disease. Subsequent evaluation with MRI and dedicated thin-section CT revealed this area to be benign fibrous dysplasia of the bone. The focal uptake on PET/CT with [¹¹C]choline in benign fibrous dysplasia represents a potential mimicker of metastatic disease. Due to recognizing this benign process, our patient was able to avoid systemic treatment and/or focal radiation and was treated with cryotherapy for biopsy-proven local recurrence within the prostate bed. While benign fibrous dysplasia can demonstrate increased radiotracer uptake on other modalities (i.e., bone scintigraphy, FDG PET/CT), its appearance on [¹¹C]choline PET/CT has been largely overlooked in the literature. With the increasing use of [¹¹C]choline PET/CT for biochemical recurrent prostate cancer evaluation, it is important to understand this potential mimicker of disease.