[18F]FDG-PET/CT Demonstration of Young Adult Onset Stills Disease Mimicking Lymphoma.

Adult-onset Still's disease (AOSD) is an inflammatory disease of unknown aetiology, with no specific diagnostic tests. A 17-year-old female presented with fevers, night sweats and weight loss. Markedly FDG avid lymphadenopathy, and diffuse marrow and splenic uptake were demonstrated on [18F]FDG-PET/CT, most suggestive of lymphoma. After extensive investigations, the working diagnosis of AOSD was made. Other conditions, such AOSD, in addition to lymphoproliferative disorders, should be considered in the differential diagnosis of widespread avid lymphadenopathy in a teenager/young adult.

Bilateral Avid Axillary Nodes on FDG PET/CT Due to Concurrent Booster COVID-19 Immunization and Seasonal Influenza Vaccination.

ABSTRACT: In an attempt to protect the high-risk demographic and reduce burden on health care systems, concomitant administration of COVID-19 and influenza vaccines has been recommended by health bodies. The ComFluCOV trial indicates this is well tolerated with no reduction in immune response to either vaccine. A 48-year-old woman with right oropharyngeal squamous cell carcinoma underwent postradiotherapy FDG PET/CT, which demonstrated complete metabolic response. Incidental avid bilateral axillary lymphadenopathy of benign configuration was noted and concluded to be reactive in response to recent Pfizer-BioNTech booster and influenza vaccination. This is expected to be seen more frequently over the coming months.

Systemic Immune Response Syndrome After COVID-19 Immunization-Initial and Follow-up 18F-FDG PET/CT Imaging Appearances.

ABSTRACT: A 46-year-old woman with previous history of breast cancer had follow-up 18F-FDG PET/CT 5 days after COVID-19 vaccination. In addition to avid axillary nodes, a well-documented feature, the scan demonstrated diffuse splenic and marrow uptake. Clinical history, laboratory, and scan findings were in keeping with SIRS (systemic inflammatory response). The patient recovered with supportive management. On follow-up, 18F-FDG PET/CT imaging 3 months later features had resolved. SIRS after vaccination may be observed on 18F-FDG PET/CT.

Incidental [18F]PSMA-1007 Appendiceal Uptake Mimicking Nodal Disease.

ABSTRACT: When interpreting an [18F]prostate specific membrane antigen (PSMA)-1007 PET/CT, it is important to understand the normal biodistribution of the tracer. A 73-year-old man with prostate cancer underwent [18F]PSMA-1007 PET/CT for biochemical recurrence. There was no abnormal uptake in the prostatectomy bed, but PSMA-avid pelvic nodal disease was found. Incidental intense focal uptake was also noted corresponding to the tip of the appendix, which was concluded to be physiological. This is an example of an uncommon site of physiological uptake of [18F]PSMA-1007 in the appendix.

Features of Systemic Immune Response From COVID-19 Vaccination on 18F-FDG PET/CT.

ABSTRACT: The rapid rollout of COVID-19 vaccination is accompanied by incidental findings on 18F-FDG PET/CT. Most cases describe reactive axillary lymphadenopathy. A 46-year-old woman with previous history of stage 3A breast cancer underwent follow-up 18F-FDG PET/CT, which demonstrated avid left axillary nodes and intense diffuse splenic uptake and moderate diffuse bone marrow uptake. She had been administered COVID-19 vaccination in the left deltoid 1 week earlier and required hospitalization for 24 hours due to fever. Symptoms settled with supportive treatment. One month after the PET/CT scan, she remained well. Sites of uptake were taken to relate to a systemic immune response.

Increased FDG Uptake of the Pectoral Girdle and Serratus Anterior Due to Wallpaper Stripping on PET/CT-Exquisite Demonstration of the Biomechanics.

ABSTRACT: According to published guidelines and routine procedures, patients are instructed to avoid strenuous exercise for 6 to 24 hours before FDG imaging, avoiding unfavorable muscular uptake. A 40-year-old man with esophageal carcinoma underwent FDG PET/CT for response assessment. Intense uptake was noted in the muscles of the right upper limb and chest. The patient stated he had avoided exercise before scanning. On further questioning, he was found to be a professional painter and decorator and had been working stripping wallpaper. Marked skeletal FDG uptake occurs in subjects who have strenuously exerted themselves before or after the injection of FDG.

False-Positive Axillary Lymph Nodes on FDG PET/CT Resulting From COVID-19 Immunization.

ABSTRACT: World-wide mass COVID-19 vaccination has been deployed starting with those most vulnerable, including the elderly and cancer patients. A 70-year-old man with right lung cancer underwent staging FDG PET/CT, which demonstrated an avid right lung mass with avid hilar and mediastinal nodes. Avid left axillary nodes of benign configuration were also noted. The patient had the Oxford-AstraZeneca COVID-19 vaccination in the left arm a week earlier. On reflection, the axillary nodes were concluded to be reactive related to this. This is a potential COVID-19 vaccination associated pitfall on PET/CT that should be considered when interpreting FDG PET/CT images.

Infection Control of COVID-19: Surgical Mask-Related Facial Cutaneous Artifact on FDG PET/CT.

ABSTRACT: In accordance with published international COVID-19 pandemic guidance (American College of Nuclear Medicine, British Nuclear Medicine Society, and European Association of Nuclear Medicine), the use of face masks has become an essential part of infection control for both patients and staff. A 56-year-old man with mantle cell lymphoma underwent staging FDG PET/CT, which demonstrated avid lymphadenopathy below the diaphragm and an unusual diffuse FDG uptake projected over the face, raising the suspicion of cutaneous lymphomatous involvement. On reflection of the clinical scenario and scanning conditions, cutaneous involvement was discounted; the pattern of uptake and lack of CT correlate were supportive of a cutaneous artifact related to the presence of the patient's mask.

Pembrolizumab-Induced Thyroiditis and Colitis-Presentation and Resolution on Serial FDG PET/CT.

ABSTRACT: A 58-year-old man with previous melanoma of the left leg underwent whole-body 18F-FDG PET/CT to stage metastatic disease prior to commencing pembrolizumab. Follow-up FDG PET/CT after 3 months of treatment showed partial metabolic response of soft tissue and nodal metastases and diffuse increased thyroid and colonic uptake, suggestive of thyroiditis and colitis. Pembrolizumab was ceased, and a repeat FDG PET/CT scan showed regression of uptake in the thyroid gland and colon, in keeping with resolution of inflammatory change. Immune-related adverse events induced by Immune checkpoint inhibitors, such as pembrolizumab, should be recognized-cessation of treatment often leads to resolution.