Amirkhani Z, Saber Tanha A, Sadeghi R
… +1 more, Ataei Nakhaei S
Clin Nucl Med
· 2026 May · PMID 42148863
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We present a case illustrating a diagnostic pitfall on 68Ga-PSMA PET/CT in a 67-year-old man with newly diagnosed prostate adenocarcinoma (Gleason score 4 + 3). Staging imaging demonstrated a solitary, distant PSMA-avid...We present a case illustrating a diagnostic pitfall on 68Ga-PSMA PET/CT in a 67-year-old man with newly diagnosed prostate adenocarcinoma (Gleason score 4 + 3). Staging imaging demonstrated a solitary, distant PSMA-avid focus at the thoracic inlet. The lesion's characteristic paravertebral location, consistent with the stellate ganglion, favored a non-prostate cancer-related etiology; however, the marked intensity of radiotracer uptake was more suggestive of metastatic disease. Histopathologic evaluation confirmed a ganglioneuroma. This case underscores that ganglioneuromas may exhibit high PSMA avidity and should be recognized to prevent false-positive interpretation on PSMA-targeted imaging.
Clin Nucl Med
· 2026 May · PMID 42148859
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A 33-year-old woman, who underwent right salpingo-oophorectomy with total hysterectomy for right ovarian yolk sac tumor 28 months ago, was referred for FDG PET/CT to evaluate possible left ovarian metastasis detected on...A 33-year-old woman, who underwent right salpingo-oophorectomy with total hysterectomy for right ovarian yolk sac tumor 28 months ago, was referred for FDG PET/CT to evaluate possible left ovarian metastasis detected on CT. FDG PET/CT showed an irregular solid mass with peripheral activity and central photonpenic area in the left pelvis. The mass showed ring-like activity on the axial plane and tennis racket-like activity on the oblique coronal plane. Left adnexal metastasis with central necrosis was suspected. Left salpingo-oophorectomy revealed adnexal torsion with necrosis, hemorrhage, and inflammatory cell infiltration, and no malignancy.
Clin Nucl Med
· 2026 May · PMID 42148857
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Fibroblast activation protein inhibitor (FAPI) PET targets cancer-associated fibroblasts and has demonstrated high uptake in advanced colorectal cancer. However, its performance in early lesions remains unclear. A man in...Fibroblast activation protein inhibitor (FAPI) PET targets cancer-associated fibroblasts and has demonstrated high uptake in advanced colorectal cancer. However, its performance in early lesions remains unclear. A man in his 70s underwent FDG PET/CT and 18F FAPI-74 PET/CT for follow-up of hepatocellular carcinoma. FDG PET showed intense focal uptake in the sigmoid colon, whereas FAPI PET demonstrated no abnormal uptake. Endoscopic resection revealed carcinoma in adenoma confined to the lamina propria without desmoplastic reaction. FAPI uptake reflects stromal fibroblast activity and may therefore be limited in intramucosal adenoma-dominant lesions.
Usmani S, Al Riyami K, Jain A
… +2 more, Al Busaidi A, Ismaila A
Clin Nucl Med
· 2026 May · PMID 42148854
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68Ga-FAPI PET/CT has emerged as a promising molecular imaging modality targeting cancer-associated fibroblasts, rather than tumor cells. We report a novel physiological uptake pattern on 68Ga-FAPI PET/CT in a 56-year-old...68Ga-FAPI PET/CT has emerged as a promising molecular imaging modality targeting cancer-associated fibroblasts, rather than tumor cells. We report a novel physiological uptake pattern on 68Ga-FAPI PET/CT in a 56-year-old woman with newly diagnosed invasive lobular carcinoma of the right breast undergoing staging. 68Ga-FAPI PET/CT demonstrated intense tracer uptake in the primary right breast tumor and a right level I axillary lymph node, consistent with FAPI expression in the primary malignancy and suspicious nodal involvement. In addition, bilateral linear, rope-like tracer uptake extending from the uterus through the inguinal canals along the round ligaments was observed, creating an "Alien Antenna" appearance. Recognition of this physiological uptake pattern is essential to avoid misinterpretation as peritoneal or metastatic disease.
Clin Nucl Med
· 2026 May · PMID 42148842
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Primary adrenal liposarcoma is very rare, accounting for only 0.2% of primary adrenal tumors. Primary bilateral adrenal liposarcoma is even rarer. We describe FDG PET/CT findings in a case of primary bilateral adrenal de...Primary adrenal liposarcoma is very rare, accounting for only 0.2% of primary adrenal tumors. Primary bilateral adrenal liposarcoma is even rarer. We describe FDG PET/CT findings in a case of primary bilateral adrenal dedifferentiated liposarcoma. The bilateral adrenal tumors showed intense FDG uptake with SUVmax of 32 and 44 for the right and left adrenal tumors, respectively. This case indicates that dedifferentiated liposarcoma should be included in the differential diagnosis of FDG-avid bilateral adrenal lesions, including adrenocortical carcinoma, pheochromocytoma, lymphoma, metastasis, and infection.
Charbel C, Woo S, Becker AS
… +7 more, Bruzzese A, Leithner D, Mayerhoefer ME, Dimitrova M, Mehnert J, Polsky D, Vargas HA
Clin Nucl Med
· 2026 May · PMID 42148841
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PURPOSE OF THE REPORT: To determine the prevalence, etiology, and clinical significance of incidental focal small bowel FDG uptake in patients undergoing PET/CT for staging of non-small bowel cancers. MATERIAL AND METHOD...PURPOSE OF THE REPORT: To determine the prevalence, etiology, and clinical significance of incidental focal small bowel FDG uptake in patients undergoing PET/CT for staging of non-small bowel cancers. MATERIAL AND METHODS: Retrospective review of consecutive FDG PET/CT examinations obtained for cancer staging with incidental focal small bowel radiotracer uptake was performed. Exclusion criteria included known small bowel pathology or insufficient reference standard. Imaging findings assessed included lesion location, number, CT correlate, SUVmax, and presence of metastases outside the bowel. Clinical data included age, sex, cancer clinical setting, origin, and stage. Focal small bowel FDG uptake etiology (benign vs. metastatic) was determined by composite reference standard (histopathology, clinical, and imaging follow-up). Statistical analyses included Wilcoxon rank-sum test, Pearson's χ2 test, Fisher exact test, and ROC curve analyses. RESULTS: In a review of 147,516 PET/CT examinations, incidental focal small bowel FDG uptake was rare, with a prevalence of 0.1% (88/147,516). Most cases were metastatic, 60.2% (53/88), most commonly spread from lymphoma [32.1% (17/53)] and melanoma [30.2% (16/53)]. Metastatic lesions were evenly distributed throughout the ileum [47.2% (25/53)] and jejunum [39.6% (21/53)]. Metastatic focal small bowel FDG uptake was associated with presence of other sites of distant metastases, higher SUVmax, and presence of a CT correlate (P <0.01). CONCLUSIONS: Incidental focal small bowel FDG uptake is rare. Most small bowel hypermetabolic foci are metastatic and are predominantly encountered with melanoma and lymphoma. Multiple imaging and clinical factors helped differentiate between benign and metastatic focal small bowel FDG uptake.
El Yaagoubi Y, Prunier-Aesch C, Wargnier O
… +2 more, Philippe L, Pasquesoone H
Clin Nucl Med
· 2026 May · PMID 42148834
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A 59-year-old woman runner was referred for left knee pain, with suspicion of stress fracture of the lateral femoral condyle. 99mTc-HDP bone scintigraphy using a new 3D-ring CZT system (StarGuide) was performed. Blood po...A 59-year-old woman runner was referred for left knee pain, with suspicion of stress fracture of the lateral femoral condyle. 99mTc-HDP bone scintigraphy using a new 3D-ring CZT system (StarGuide) was performed. Blood pool SPECT/CT revealed hyperemia between the iliotibial band and the lateral femoral condyle of the left knee, suggestive of iliotibial band syndrome (ITBS), while late-phase SPECT/CT did not demonstrate any abnormality in the left knee. The patient underwent an MRI, which confirmed ITBS. Our case emphasizes the potential of blood pool SPECT/CT using a new 3D-ring CZT system to identify relevant extraosseous conditions such as ITBS.
Clin Nucl Med
· 2026 May · PMID 42148832
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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 t...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.
Oksuzoglu K, Perktas L, Onner H
… +1 more, Yilmaz F
Clin Nucl Med
· 2026 May · PMID 42148830
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PSMA is a critical cell-surface molecule and 68Ga-PSMA PET has become an established imaging modality that improves disease localization for newly diagnosed and recurrent prostate cancer. We report a patient with wedge-s...PSMA is a critical cell-surface molecule and 68Ga-PSMA PET has become an established imaging modality that improves disease localization for newly diagnosed and recurrent prostate cancer. We report a patient with wedge-shaped increased PSMA uptake in segment VIII of the liver. MRI demonstrated no focal lesion; however, mild diffusion hyperintensity without apparent diffusion coefficient reduction and transient arterial hyperenhancement were observed. These findings were consistent with a perfusion-related pseudolesion rather than metastatic disease.
Clin Nucl Med
· 2026 May · PMID 42148828
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A giant bone island, defined as having a diameter >2.0 cm, 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-defin...A giant bone island, defined as having a diameter >2.0 cm, 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 2.2 cm 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.
Clin Nucl Med
· 2026 May · PMID 42113837
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Thyroid metastasis from clear cell renal cell carcinoma (ccRCC) is uncommon. The imaging findings were reported in a 77-year-old ccRCC woman with thyroid metastasis using carbonic anhydrase IX (CAIX)-targeted PET/CT. Int...Thyroid metastasis from clear cell renal cell carcinoma (ccRCC) is uncommon. The imaging findings were reported in a 77-year-old ccRCC woman with thyroid metastasis using carbonic anhydrase IX (CAIX)-targeted PET/CT. Intense radiotracer uptake was observed not only in the primary renal tumor, but also in a focal lesion in the left thyroid lobe. This case highlights the potential utility of CAIX-targeted PET/CT imaging for visualizing primary and metastatic ccRCC, including uncommon metastatic sites.
Pan Q, Liu S, Zhang H
… +3 more, Chang L, Cao X, Luo Y
Clin Nucl Med
· 2026 May · PMID 42113823
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BACKGROUND: Waldenström macroglobulinemia/lymphoplasmacytic lymphoma (WM/LPL) is a rare, indolent non-Hodgkin lymphoma. Bruton tyrosine kinase inhibitors (BTKis) have been widely used for the treatment of WM/LPL. The obj...BACKGROUND: Waldenström macroglobulinemia/lymphoplasmacytic lymphoma (WM/LPL) is a rare, indolent non-Hodgkin lymphoma. Bruton tyrosine kinase inhibitors (BTKis) have been widely used for the treatment of WM/LPL. The objective of this study is to evaluate the response assessed by 68Ga-pentixafor PET/CT in patients with WM/LPL treated with either BTKi or chemoimmunotherapy. PATIENTS AND METHODS: This is a post hoc analysis of the data from our prospective cohort study. A total of 33 patients with newly diagnosed or relapsed WM/LPL were included. The clinical response was assessed using the International Workshop of WM (IWWM) response criteria based on the change of monoclonal protein level. 68Ga-pentixafor PET/CT response was evaluated both visually and semiquantitatively. The total lesion uptake (TLU), metabolic tumor volume (MTV), and SUVmax were measured for semiquantitative assessments and were calculated as percentage change from baseline to follow-up scans (∆TLU%, ∆MTV%, ∆SUVmax%). The change of M-protein (∆M-pro%) and IgM (∆IgM%) was also calculated. RESULTS: Among the included patients, 15 received chemoimmunotherapy (chemo-group), while 18 patients were treated with BTKi-containing regimens (BTKi group). In PET/CT visual assessment, 14/15 (93.3%) patients in chemo-group exhibited consistent response, as assessed by 68Ga-pentixafor PET/CT and M-protein-based IWWM criteria. However, the PET/CT-based response was inconsistent with the IWWM response in 10/18 (55.6%) patients in the BTKi group. For semiquantitative analysis, ∆TLU%, ∆MTV%, and ∆SUVmax% in chemo-group showed a strong correlation with clinical response, ∆M-pro%, and ∆IgM% values (r = 0.634-0.856, P < 0.05). However, there was no statistically significant correlation between the changes in M-protein percentage or IgM percentage and the uptake values measured by 68Ga-pentixafor PET/CT in BTKi group (P > 0.05). CONCLUSIONS: 68Ga-pentixafor PET/CT provides accurate response assessment in WM/LPL patients receiving chemoimmunotherapy. However, the 68Ga-pentixafor PET/CT-based response exhibited inconsistency with the M-protein-based IWWM criteria in those treated with BTKis, thereby suggesting the potential inadequacy of the IWWM response criteria in WM/LPL patients treated with BTKis.
Sheikhnezami M, Samadi MH, Sadeghi R
… +3 more, Askari E, Khorasanchi A, Saber Tanha A
Clin Nucl Med
· 2026 May · PMID 42113821
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We report a 71‑year‑old woman with recurrent gastric adenocarcinoma presenting with colonic wall involvement on follow-up contrast-enhanced CT scan. Initial restaging 18F‑FDG PET/CT demonstrated intense colonic and oment...We report a 71‑year‑old woman with recurrent gastric adenocarcinoma presenting with colonic wall involvement on follow-up contrast-enhanced CT scan. Initial restaging 18F‑FDG PET/CT demonstrated intense colonic and omental uptake, consistent with recurrent malignancy. After chemotherapy, follow‑up 18F-FDG PET/CT showed marked metabolic improvement; however, concurrent ⁶⁸Ga‑FAPI PET/CT revealed persistent intense uptake in the colonic wall, peritoneum, and omentum, closely resembling that observed on the prior 18F-FDG PET/CT, correlating with ongoing clinical deterioration. This discordance suggests differential treatment response between tumor cells and cancer‑associated fibroblasts. Our findings raise the hypothesis that persistent tumor microenvironment activity may underlie therapeutic resistance, highlighting the potential value of early integration of FAP‑targeted strategies alongside tumor‑directed therapies.
Clin Nucl Med
· 2026 May · PMID 42113819
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A 40-year-old woman, who underwent modified radical mastectomy and chemoradiotherapy for triple-negative left breast cancer, presented with increasing lymphedema of the proximal left upper limb of 2 years' duration. She...A 40-year-old woman, who underwent modified radical mastectomy and chemoradiotherapy for triple-negative left breast cancer, presented with increasing lymphedema of the proximal left upper limb of 2 years' duration. She underwent 18F-FDG PET/CT (FDG) and 68Ga-FAPI-04 PET/CT (FAPI) scans, which showed subcutaneous deposits that were more FAPI-avid than FDG. These were diagnosed as Stewart-Treves syndrome (STS), which is a rare, highly aggressive angiosarcoma arising in chronic lymphedema. Better performance of FAPI vis-à-vis FDG scan may aid in early diagnosis and timely intervention in this rare, albeit clinically important, pathology in breast cancer patients with chronic lymphedema.
Iakovoglou D, Paschali A, Kalathas T
… +2 more, Lafaras C, Chatzipavlidou V
Clin Nucl Med
· 2026 May · PMID 42113569
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Reporting incidental 18F-FDG PET/CT findings that require further evaluation or urgent treatment is critical, as they can have a major impact on a patient's management. Among the possible alert findings, those related to...Reporting incidental 18F-FDG PET/CT findings that require further evaluation or urgent treatment is critical, as they can have a major impact on a patient's management. Among the possible alert findings, those related to the heart may be the most challenging due to the variety of physiological 18F-FDG uptake in the myocardium in standard PET/CT imaging with 4-6 hours fasting. We report a case of an 84-year-old man with rectosigmoid adenocarcinoma, without known coronary artery disease, who underwent 18F-FDG PET/CT for staging. An incidental striking focal uptake in the left ventricle accompanied by clinical symptoms, prompted further evaluation, which confirmed acute myocardial ischemia.
A 16-year-old boy with high-risk neuroblastoma underwent a routine follow-up 123I-MIBG scan, which revealed increased radiotracer uptake in the left upper abdomen, localized to the left celiac ganglion. Subsequent abdomi...A 16-year-old boy with high-risk neuroblastoma underwent a routine follow-up 123I-MIBG scan, which revealed increased radiotracer uptake in the left upper abdomen, localized to the left celiac ganglion. Subsequent abdominal ultrasound showed no structural abnormalities in this region, and additional laboratory tests did not indicate signs suggestive of disease recurrence. A repeat 123I-MIBG scan performed 6 months later demonstrated no abnormal uptake. This case highlights that physiological uptake in the celiac ganglion may mimic pathological findings, leading to potential false-positive interpretation of 123I-MIBG scans.
We report a woman in her 20s with alveolar rhabdomyosarcoma treated with Wilms tumor 1 (WT1) peptide vaccination administered as an investigational immunotherapy. Serial PET/CT demonstrated intense FDG uptake at the inje...We report a woman in her 20s with alveolar rhabdomyosarcoma treated with Wilms tumor 1 (WT1) peptide vaccination administered as an investigational immunotherapy. Serial PET/CT demonstrated intense FDG uptake at the injection site with progressive skin thickening and calcification. Remarkably, FDG uptake continued to increase after vaccination cessation, peaking at 49 months before gradually declining. Unlike transient inflammation seen with conventional vaccines, WT1 vaccination induces prolonged FDG uptake due to the oil-based adjuvant Montanide, causing chronic inflammation and granuloma formation. Recognition of this characteristic course is essential to avoid misdiagnosis as cutaneous metastasis.
The 18 F-FDG and 68 Ga-FAPI-04 PET/CT imaging findings were reported in a 52-year-old man with hepatocellular carcinoma (HCC) 3 weeks after undergoing yttrium-90 selective internal radiation therapy ( 90 Y-SIRT). Both vi...The 18 F-FDG and 68 Ga-FAPI-04 PET/CT imaging findings were reported in a 52-year-old man with hepatocellular carcinoma (HCC) 3 weeks after undergoing yttrium-90 selective internal radiation therapy ( 90 Y-SIRT). Both viable tumors and tumor thrombus of right portal vein showed mild-to-moderate 18 F-FDG uptake, while peritumoral tissues showed high 68 Ga-FAPI-04 uptake, the range of which approximately matched radiotracer distribution on 90 Y SPECT/CT. Our findings indicate that 18 F-FDG PET/CT is superior to 68 Ga-FAPI-04 PET/CT for identifying viable HCC tumors during early 90 Y-SIRT monitoring, whereas 68 Ga-FAPI-04 PET/CT indirectly delineates the area of 90 Y-SIRT.
Seventy-three-year-old man with previous diagnosis of bladder carcinoma with suspicious pulmonary nodule and rectum polypoid lesion in a follow-up 18F fluorodeoxyglucose PET-CT examination. The histopathology results rev...Seventy-three-year-old man with previous diagnosis of bladder carcinoma with suspicious pulmonary nodule and rectum polypoid lesion in a follow-up 18F fluorodeoxyglucose PET-CT examination. The histopathology results revealed lung adenocarcinoma as well as rectum adenocarcinoma and ring cell tumor of the stomach, which was additionally determined by the 68Ga Trivehegzin PET-CT imaging.