The spontaneous regression of metastatic lesions from renal cell carcinoma (RCC) is extremely rare, but may be encountered following cytoreductive treatments. We report a case of a recurrent RCC with multiple metastatic lesions which spontaneously regressed after undergoing radiofrequency ablation of the renal tumor.
Adrenal Gland Neoplasms/radiography/*secondary ; Aged, 80 and over ; Carcinoma, Renal Cell/radiography/*secondary/*surgery ; *Catheter Ablation ; Humans ; Kidney Neoplasms/*pathology/radiography/*surgery ; Lung Neoplasms/radiography/*secondary ; Male ; Neoplasm Recurrence, Local ; Remission, Spontaneous ; Tomography, X-Ray Computed

OBJECTIVE: The aim of this study was to assess the diagnostic efficacy of integrated PET/CT using fluorodeoxyglucose (FDG) for the differentiation of benign and metastatic adrenal gland lesions in patients with lung cancer and to compare the diagnostic efficacy with the use of PET alone. MATERIALS AND METHODS: Sixty-one adrenal lesions (size range, 5-104 mm; mean size, 16 mm) were evaluated retrospectively in 42 lung cancer patients. Both PET images alone and integrated PET/CT images were assessed, respectively, at two-month intervals. PET findings were interpreted as positive if the FDG uptake of adrenal lesions was greater than or equal to that of the liver, and the PET/CT findings were interpreted as positive if an adrenal lesion show attenuation > 10 HU and showed increased FDG uptake. Final diagnoses of adrenal gland lesions were made at clinical follow-up (n = 52) or by a biopsy (n = 9) when available. The diagnostic accuracies of PET and PET/CT for the characterization of adrenal lesions were compared using the McNemar test. RESULTS: Thirty-five (57%) of the 61 adrenal lesions were metastatic and the remaining 26 lesions were benign. For the depiction of adrenal gland metastasis, the sensitivity, specificity, and accuracy of PET were 74%, 73%, and 74%, respectively, whereas those of integrated PET/CT were 80%, 89%, and 84%, respectively (p values; 0.5, 0.125, and 0.031, respectively). CONCLUSION: The use of integrated PET/CT is more accurate than the use of PET alone for differentiating benign and metastatic adrenal gland lesions in lung cancer patients.
Adrenal Gland Neoplasms/pathology/*radiography/*radionuclide imaging/secondary ; Adult ; Aged ; Biopsy ; Diagnosis, Differential ; Female ; Fluorodeoxyglucose F18/*diagnostic use ; Humans ; Lung Neoplasms/pathology/*radiography/*radionuclide imaging ; Male ; Middle Aged ; Positron-Emission Tomography/*methods ; Radiopharmaceuticals/*diagnostic use ; Retrospective Studies ; Sensitivity and Specificity ; Tomography, X-Ray Computed/*methods