Incidental Detection of Sarcomatoid Lung Cancer by [18F] Choline Positron Emission Tomography/Computed Tomography.

A 79-year-old man treated for prostate cancer (PCa) in 2018 with concurrent hormone therapy and radical radiotherapy (RT) was given metastasis-directed RT because of skeletal progression of PCa in 2021. On [18F]-choline positron emission tomography/computed tomography (CT) for biochemical recurrence (prostate-specific antigen level: 4.96 ng/mL), he showed significant uptake in multiple skeletal lesions and focal uptake in a left lung nodule. CT-guided biopsy revealed a sarcomatoid lung carcinoma. This case confirms that histopathological evaluation is mandatory in the event of significant radiolabeled choline uptake in a single lung nodule.