Purpose: The aim of this study was to investigate the value of dual-phase ^99mTc-MIBI SPECT/CT in the differential diagnosis between benign and malignant enhancing solid renal tumors. Patients and Methods: Totally, 180 patients were imaged with dual-phase ^99mTc-MIBI SPECT/CT, which was performed 30 minutes and 90 minutes after ^99mTc-MIBI administration. Among them, 147 patients with 148 histologically proved solid renal tumors met the selection criteria and were included for the final analysis. Relative quantification was performed by measuring the radioactive uptake ratio of tumor to the normal renal parenchymal background for both early and delayed images. Results: Benign renal tumors (4 renal oncocytomas and 8 lipid-poor angiomyolipomas) demonstrated a significantly higher early relative uptake value (ERUV) and delayed relative uptake value (DRUV) than malignant renal tumors (n = 136; both P < 0.0001). The ERUV cutoff value of 0.53 helped to differentiate benign from malignant renal tumors, with sensitivity of 100%, specificity of 94.8%, and accuracy of 95.3% for the diagnosis of benign renal tumors. The DRUV cutoff value of 0.50 helped to differentiate benign from malignant renal tumors, with sensitivity of 100%, specificity of 96.3%, and accuracy of 96.6% for the diagnosis of benign renal tumors. There was no statistically significant difference between the efficacy of ERUV and DRUV in the differential diagnosis between benign and malignant renal tumors (P = 0.5). The efficacies of ERUV and DRUV were all significantly higher than the retention index (both P < 0.0001). Conclusions: Both early and delayed phase ^99mTc-MIBI SPECT/CT are helpful for distinguishing benign renal oncocytoma and lipid-poor angiomyolipoma from malignant renal tumors, and the delayed phase imaging tends to show higher diagnostic accuracy.

Prostatic ductal adenocarcinoma is an uncommon variant of prostatic carcinoma with aggressive behavior and worse prognosis. We describe ⁶⁸Ga-PSMA-11 and FDG PET/CT findings in a case of prostatic ductal adenocarcinoma with pelvic lymph node metastases. The majority of the prostate tumor and all the metastatic lesions showed no significant PSMA uptake but intense FDG uptake. The role of PSMA and FDG PET in the management of prostatic ductal adenocarcinoma needs to be investigated in a large number of patients.

A 65-year-old man with treated prostate adenocarcinoma underwent ⁶⁸Ga-PSMA-11 PET/CT scan for restaging due to significantly increased serum PSA levels. PET/CT showed bilateral adrenal masses with high ⁶⁸Ga-PSMA-11 uptake. There was no other lesion suspicious for metastasis. The laboratory and imaging findings were consisted with isolated bilateral adrenal metastases from prostate adenocarcinoma. The patient received docetaxel chemotherapy in combination with androgen deprivation therapy. PSA levels gradually decreased during chemotherapy. Follow-up MRI showed the bilateral adrenal masses significantly decreased in size. This case demonstrates the usefulness of ⁶⁸Ga-PSMA-11 PET/CT in identifying atypical metastasis from prostate adenocarcinoma.

Prostate-specific membrane antigen (PSMA) PET findings of urothelial carcinoma were rarely reported. We describe ¹⁸F-FDG PET/CT and ⁶⁸Ga-PSMA-11 PET/MRI findings in a case of urothelial carcinoma of the bladder with bone metastases in the sternum, ribs, spine, pelvis, and femurs. The bone metastases showed isodensity to hyperdensity and mild to intense FDG uptake on FDG PET/CT and moderate to intense PSMA uptake on PSMA PET/MRI. PSMA PET/MRI more clearly delineated the bone metastases compared with FDG PET/CT.

Isolated pancreatic metastasis from lung cancer is rare. We present a case of isolated pancreatic metastasis from squamous cell lung cancer. The pancreatic tumor showed hypovascularity on enhanced MRI and intense FDG uptake on FDG PET/CT mimicking primary pancreatic ductal adenocarcinoma. This case indicates pancreatic metastasis should be considered as a differential diagnosis in patients with a history of extrapancreatic cancer and hypermetabolic pancreatic lesion.

Renal metastasis from adenoid cystic carcinoma of the head and neck is uncommon. We present ^99mTc-MIBI SPECT/CT and FDG PET/CT findings in a case with isolated bilateral renal metastases from adenoid cystic carcinoma of the left maxilla. The metastatic adenoid cystic carcinomas of the kidneys showed photopenia on ^99mTc-MIBI SPECT/CT and increased FDG uptake on FDG PET/CT mimicking primary renal cell carcinoma.