Prostate cancer metastasis mimicking appendicitis—A rare but important differential diagnosis in PET/CT imaging

Prostate cancer most commonly metastasizes to lymph nodes, bones, the liver, and the lungs. Prostate cancer carcinomatosis with an affinity for the appendix is not well described in current literature and is usually reported with acute appendicitis as the primary presentation. A 65-year-old male with a history of recurrent prostate cancer presented with an increase in PSA value. 18F-PSMA-1007 PET/CT showed nodular tissue growth and increased PSMA uptake in the prostate, on the appendix, in the umbilicus, and in several intra- and extra pelvic lymph nodes. The patient had no symptomatic complaints at time of referral. Imaging findings of the appendix resembling characteristic findings of acute appendicitis raised doubts about the interpretation of these as inflammatory disease or peritoneal carcinomatosis secondary to prostate cancer. This case demonstrates the importance of correct differentiation between the 2 conditions based on imaging, clinical symptomatology, and patient history to provide proper care in time.