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Benign metabolic uptake on fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) is not uncommonly seen after immunization. We report a case of 30-year-old man with Hodgkin's lymphoma who underwent two cycles of chemotherapy. Interim 18F-FDG PET/computed tomography demonstrated complete metabolic response of prior hypermetabolic bilateral supraclavicular and mediastinal lymph nodes. Although multiple new normal-sized hypermetabolic left axillary and subpectoral lymph nodes are noted, relevant history revealed COVID vaccine 7 days prior scan with mild FDG uptake at the left deltoid muscle. These new findings at the left axilla are likely related to recent vaccination. 18F-FDG PET uptake in the lymph nodes is not so uncommon after immunization; relevant history is very important especially in the phase of massive immunization to avoid false interpretation. [ABSTRACT FROM AUTHOR]

The dissemination and autotransplantation of viable splenic tissue in different anatomic compartments of the body can present a diagnostic dilemma, especially when metastatic disease is suspected. We report a case of a 30-year-old male with well-differentiated gastric neuroendocrine tumor (Grade II) treated with surgery. Follow-up 68Ga-DOTA-NOC demonstrated a suspicious peritoneal soft-tissue nodule in the right paracolic gutter with increased tracer uptake. In view of splenectomy 10 years ago, the patient underwent 99mTc heat-denatured erythrocyte study which showed a very unusual pattern of multiple tracer-avid foci of splenic tissue in both intraperitoneal and extraperitoneal distributions. The integration of the patient's history and complementary nuclear imaging results led to the correct diagnosis of splenosis. [ABSTRACT FROM AUTHOR]

Nivolumab, an immune checkpoint inhibitor, is a humanized anti-programmed death-1 monoclonal antibody that is used for the treatment of various cancers after second-line chemotherapy. We report a 23-year-old male with relapsed Hodgkin's lymphoma Stage IV treated with nivolumab. After 3 months of treatment, he developed watery diarrhea and cramping abdominal pain. Follow-up positron emission tomography-computed tomography scan showed complete metabolic resolution of the disease; however, there is bowel wall thickening and colonic distension with corresponding increased fluorodeoxyglucose uptake. These findings are related to immune-related adverse event associated with nivolumab treatment, i.e., secondary enterocolitis. These adverse events can be successfully treated if timely and appropriately diagnosed. [ABSTRACT FROM AUTHOR]

68Ga-prostate-specific membrane antigen (68Ga-PSMA) is expressed in the endothelium of tumor-associated neovasculature of various solid malignancies possibly due to tumor-associated angiogenic factors and endothelial cell sprouting. We report a case of a 45-year-old man with known colorectal cancer, cirrhosis, and hepatitis C. Contrast-enhanced computed tomography (CT) showed a hypervascular lesion in the liver, and 18F-fluorodeoxyglucose positron emission tomography (PET) did not show any suspicious hepatic uptake. 68Ga-PSMA PET-CT showed predominantly heterogeneous perilesional uptake in a configuration similar to the arterial enhancement pattern on the diagnostic CT. 68Ga-PSMA uptake in hepatocellular carcinoma appears to be primarily neoangiogenesis driven, and its morphological and functional characterization can subsequently influence the selection of anti-neoangiogenic chemotherapy agents as well as guiding radionuclide ligand therapy. [ABSTRACT FROM AUTHOR]

Adductor insertion avulsion syndrome, also known as "thigh splints," is a painful condition affecting the proximal to mid-femur at the insertion of the adductor muscles of the thigh. 18F-Sodium fluoride (18F-NaF) is increasingly used in diagnosing skeletal pain which is not identified on radiographs. We report a case of a 56-year-old morbidly obese woman with left hip pain referred for 18F-NaF positron emission tomography-computed tomography (PET-CT) as magnetic resonance imaging cannot be performed due to obesity. 18F-NaF PET-CT shows an increase in tracer uptake at the posteromedial cortex of the upper shaft of left femur. Findings are likely due to adductor insertion avulsion syndrome. 18F-NaF provides important diagnostic information that might alter treatment options. [ABSTRACT FROM AUTHOR]