Systematic review of PET imaging features and clinical applications in pulmonary NUT carcinoma.

PURPOSE: Primary pulmonary nuclear protein in testis (NUT) carcinoma is a rare, aggressive malignancy driven by NUTM1 rearrangement. Although 18F-FDG PET/CT is used in clinical management, its imaging features and value have not been systematically evaluated. METHODS: This PRISMA 2020 systematic review was registered with PROSPERO (CRD420261292692). PubMed, Embase, Web of Science, Cochrane Library, and grey literature were searched from inception to March 2026. Studies reporting 18F-FDG PET/CT findings in pathologically confirmed primary pulmonary NUT carcinoma were included. A structured qualitative synthesis was performed. RESULTS: Twenty-three studies (86 patients) were included. Tumours consistently showed marked hypermetabolism (SUVmax 5-40; mean, 12-14) with frequent central necrosis. A proposed imaging triad was identified: (1) bulky central mass with necrosis; (2) ipsilateral coalescent mediastinal/hilar lymphadenopathy; and (3) extensive ipsilateral pleural involvement. The contralateral lung remained relatively spared and brain metastases were rare at initial diagnosis. PET/CT led to M-stage reclassification in 55% of patients through occult metastasis detection, was superior to bone scintigraphy for osteolytic lesions, and revealed initial treatment response followed by rapid progression on serial monitoring. CONCLUSIONS: Primary pulmonary NUT carcinoma demonstrates a characteristic hypermetabolic phenotype with a proposed imaging triad on 18F-FDG PET/CT. PET/CT is crucial for staging modification, metastasis detection, and treatment response monitoring. Recognition of this profile may facilitate earlier diagnosis and clinical management. SYSTEMATIC REVIEW REGISTRATION: https://www.crd.york.ac.uk/PROSPERO/view/CRD420261292692, identifier CRD420261292692.