A 58-year-old man with a history of lithotripsy for urolithiasis presented with persistent fever and pollakisuria. As empirical anti-infective therapy was ineffective, 18 F-FDG PET/CT was performed to detect potential malignancy, revealing bilateral renal enlargement with multiple nodular cortex uptakes and an enlarged left axillary lymph node, suggestive of pyelonephritis. However, biopsies of the axillary lymph node and right kidney confirmed high-grade diffuse large B-cell lymphoma (DLBCL). Following R-DA-EPOCH chemotherapy, the patient achieved sustained remission. This case highlights that renal DLBCL can mimic pyelonephritis on 18 F-FDG PET/CT, and PET/CT is instrumental in guiding biopsy for accurate diagnosis.

A 60-year-old woman with cervical squamous cell carcinoma received 18F-FDG PET/CT for tumor surveillance because of increased serum CA-125. PET/CT images showed multiple left pleural foci and nodular thickening of the pleura at the corresponding sites. Then, the pathology after CT-guided biopsy confirmed that the pleural foci were metastases from the cervical carcinoma.

A 56-year-old man presented with hyperglycemia and weight loss. Imaging revealed a pancreatic head mass with features suggestive of primary pancreatic carcinoma. 18F-FDG PET/CT confirmed a hypermetabolic lesion without evidence of distant metastasis. Following the Whipple procedure, histopathology and immunohistochemistry (CD34+, Vimentin+), together with a history of resected ankle sarcoma, established the diagnosis of a solitary pancreatic metastasis from dermatofibrosarcoma protuberans (DFSP). This case highlights the diagnostic difficulty posed by solitary pancreatic metastases, which can closely mimic primary pancreatic cancer. A comprehensive approach integrating clinical history, tumor markers, and multimodality imaging is essential for accurate differentiation.

A 42-year-old man with a recent medical history of multiple myeloma and associated chemotherapy presented with a rapidly growing anal mass for 2 months. PET/CT showed a soft tissue mass with increased 18F-FDG uptake in the anus. The surgical pathology indicated a moderately to well-differentiated angiosarcoma of the anus.

A giant bone island, defined as having a diameter >2.0cm, is rare. We describe 18F-PSMA-1007 PET/CT findings in a patient with a giant bone island in the left femoral head. The giant bone island appeared as a well-defined sclerotic lesion measuring 2.2cm in maximum diameter on CT and showed mild 18F-PSMA-1007 uptake on PET. The increased PSMA uptake may suggest a possible PSMA expression related to osteoblastic activity.

To prospectively compare the diagnostic value of 18 F-meta-fluorobenzylguanidine ([ 18 F]MFBG) and [ 68 Ga]Ga-DOTA-TATE PET/CT in pediatric patients with suspected recurrent/refractory neuroblastoma. Between December 2024 and March 2025, 28 children (18 boys, 10 girls; mean age ± SD 4.8 ± 2.5y) underwent both tracers within 1 week at a single institution. Physiological biodistribution, image quality, lesion conspicuity, semiquantitative uptake (SUVmax), Curie score, and response classification were analyzed side-by-side. [ 18 F]MFBG showed higher background than [ 68 Ga]Ga-DOTA-TATE in skeletal muscle but lower activity in articular metaphyses, pituitary, and kidneys. Heterogeneous distribution of [ 18 F]MFBG was more common in the liver, while notable uptake differences were observed in the pancreas with [ 68 Ga]Ga-DOTA-TATE. Patient-level concordance was high (both scans positive in 15, negative in 7); discordance occurred in 6 patients (2 MFBG+/DOTA-TATE-, 4 MFBG-/DOTA-TATE+). Region-level analysis encompassed 86 relapsed or metastatic regions in 17 patients. [ 18 F]MFBG detected 80 regions (sensitivity 93.0%, specificity 96.4%, AUC 0.947), whereas [ 68 Ga]Ga-DOTA-TATE detected 82 (sensitivity 95.4%, specificity 86.6%, AUC 0.910). Superior specificity of [ 18 F]MFBG stemmed largely from its higher uptake in bone/marrow metastases compared with [ 68 Ga]Ga-DOTA-TATE (median SUVmax 5.21 vs. 2.90, P <0.0001). Region-level concordance revealed 78 concordant positive sites and 39 discordant sites (9 MFBG+/DOTA-TATE-, 30 MFBG-/DOTA-TATE+). Aggregate Curie scores were identical (155 each). Because uptake patterns were complementary, combining both tracers improved visual confidence in heterogeneous tumors and refined treatment-response categorization. [ 18 F]MFBG and [ 68 Ga]Ga-DOTA-TATE PET/CT imaging are effective for evaluating relapsed or metastatic neuroblastoma because they show lower uptake in normal organs and benign lesions. The 2 imaging modalities offer complementary value in tumor detection and assessment of treatment response due to tumor spatial heterogeneity.

A 51-year-old woman presented with intermittent upper abdominal pain for two years and unintentional weight loss recently. Gastroscopy revealed a large cardia mass protruding into the gastric lumen. CT examination suggested malignant gastric tumor. Subsequently, ¹⁸F-FDG PET/CT demonstrated heterogeneous intense uptake in the gastric mass. Pathologic examination identified a gastric pyloric gland adenoma by immunohistochemistry. The lesion was resected locally, and the patient recovered well.

A man in his 60s with asbestos exposure and pleural plaques was incidentally found to have a chest wall mass on computed tomography (CT). Positron emission tomography/CT (PET/CT) demonstrated intense 18F-fluorodeoxyglucose (FDG) uptake, raising concern for malignancy, including malignant pleural mesothelioma. CT and magnetic resonance imaging (MRI), however, showed a predominantly fat-containing lesion, suggesting hibernoma. Video-assisted thoracoscopic resection was performed, and histopathology confirmed hibernoma. Recognition of macroscopic fat on CT/MRI is essential to avoid misdiagnosis of FDG-avid benign lipomatous tumors.

A 59-year-old woman with a history of recurrent pheochromocytoma underwent 18F-FDG and 18F-octreotide PET/CT to evaluate metastatic disease following progression on targeted therapy. FDG PET/CT showed intense uptake in a mass in the right adrenal bed, bones, lung nodules, and lymph nodes. Octreotide PET/CT confirmed concordant high uptake in the corresponding lesions. Germline testing revealed a VHL p.Asp126Asn mutation. This "dual-tracer" strategy provided complementary information on glucose metabolism and somatostatin receptor expression, facilitating prognostic stratification and therapeutic decision-making in VHL-mutated pheochromocytoma.

A 4-year-old girl presented with persistent fever and an abdominal mass detected on ultrasound. 18 F-FDG PET/CT revealed peripheral hypermetabolism with central photopenia in the abdominal lesion, diffuse hepatic 18 F-FDG uptake, and hepatomegaly, consistent with a hepatic superscan. Biopsy confirmed neuroblastoma metastases to the liver and bone marrow (stage IV). Postchemotherapy 123 I-MIBG SPECT/CT demonstrated absent lesion uptake but marked diffuse hepatic tracer accumulation with heterogeneous parenchymal density, fulfilling criteria for a hepatic superscan on MIBG imaging. This case illustrates dual-tracer hepatic superscans in neuroblastoma, which represents an uncommon clinical presentation.