Rationale:Giant cell arteritis (GCA) combined with concomitant pulmonary embolism (PE) is extremely difficult to diagnose because of its low incidence and atypical clinical presentations. Patient concerns:A 62-year-old male developed fever of unknown origin. Diagnoses:Positron emission tomography/computed tomography (PET/CT) revealed increased glucose metabolism in the vascular walls of the ascending and descending aorta and pulmonary artery, leading to a diagnosis of GCA combined with PE. Interventions:The patient did not respond to regular antiviral and antibacterial treatment but was remised after steroid treatment. Outcomes:No specific autoantibodies were positive for this patient, and the patient did not respond to regular antiviral and antibacterial treatment. After diagnosed by PET/CT, the patient responded well to steroid treatment. Literature review found 16 cases of GCA diagnosed by PET/CT. Their median age was 68.5 (range, 21-87) years and 13 cases were female. PET/CT showed significantly increased metabolism in the ascending and descending aorta, abdominal aorta, and carotid artery. In 4 cases (including our own case), the mean maximum standardized uptake value was 4.21.7 (range, 2.5-7.2). Six cases of GCA also had PE and 5 (6/7, 85.7%) cases were females, and the current case is the first male case of GCA combined with PE. Steroid therapy was initiated in all 5 cases. Complete remission was achieved in 4 cases and 2 patients died and the outcome of 1 patient was unknown. Lessons:Our case and the review highlight the value of PET/CT in diagnosing GCA combined with PE, suggesting that PET/CT is the preferred diagnostic tool for atypical patients presenting with fever or muscle pain.