18F-fluciclovine is a PET radiopharmaceutical used for the detection of recurrent prostate cancer in adult men after primary curative treatment with suspicion of recurrence based on elevated prostate-specific antigen level. Several incidental uptakes of 18F-fluciclovine in other tumour types have been described in the literature so far -in breast cancer, hepatocellular carcinoma, and malignant melanoma. Our case report presents a patient with oncological duplicity (prostate gland carcinoma and newly diagnosed neuroendocrine tumour) and with accumulation of fluciclovine in pathologically proved neuroendocrine tumour, later imagined also by octreotide SPECT/CT. To our knowledge, this is the first case of fluciclovine accumulated in a neuroendocrine tumour described in the literature.In conclusion, incidental FCV uptake in cancer types other than prostate cancer has already been described, with our case report adding to this list. FCV PET is a tool to detect recurrent prostate cancer with rising PSA levels. In our case, the patient had low PSA levels and FCV uptake in metastases which were later proven to be NET. AcknowledgementWe would like to thank Dr. Pavel Veselý, PhD, clinical oncologist, for his help with the clinical data of the patient. Statement of EthicsWritten informed consent was obtained from the patient for the publication of this case report and accompanying images.