Incidental Uptake of 68Ga-DOTATATE Gastrointestinal Stromal Tumor of Duodenum

Synchronous Endometrial Cancer Detected on 68 Ga-DOTATATE PET/CT

ABSTRACT

A 50-year-old woman with history of metastatic neuroendocrine tumor underwent a follow-up PET/CT with 68 Ga-DOTATATE. An enlarged uterus with diffuse increased uptake warranted further investigation with an MRI that showed mass-like thickening of the endometrium, T2 hyperintensity, lobulated contour, and invasion of more than 50% of the myometrium. Biopsy revealed endometrial carcinoma with mucinous features. Mild to moderate uptake of the 68 Ga-DOTATATE by the uterus can be a normal physiological finding; however, it should prompt further investigation, particularly in a postmenopausal woman with concerning imaging or clinical findings.

18 F-MFBG PET/CT Is an Effective Alternative of 68 Ga-DOTATATE PET/CT in the Evaluation of Metastatic Pheochromocytoma and Paraganglioma

PURPOSE

The current guidelines state that the functional imaging choice in the evaluation of metastatic pheochromocytoma and paraganglioma (PPGL) is 68 Ga-DOTATATE PET/CT. 18 F-meta-fluorobenzylguanidine ( 18 F-MFBG) is a new PET tracer and an analog of meta-iodobenzylguanidine (MIBG). This study aimed to compare 18 F-MFBG and 68 Ga-DOTATATE PET/CT in patients with metastatic PPGL.

PATIENTS AND METHODS

Twenty-eight patients with known metastatic PPGL were prospectively recruited for this study. All patients underwent both 18 F-MFBG and 68 Ga-DOTATATE PET/CT studies within 1 week. Lesion numbers detected were compared between these 2 studies.

RESULTS

18 F-MFBG PET/CT was positive for detecting metastases in all patients, whereas positive results of 68 Ga-DOTATATE PET/CT were in 27 (96.4%) patients. A total of 686 foci of metastatic lesions were detected by both 18 F-MFBG and 68 Ga-DOTATATE imaging. In addition, 33 foci of abnormal activity were only detected by 18 F-MFBG, whereas 16 foci were only shown on 68 Ga-DOTATATE PET/CT.

CONCLUSIONS

Our data suggest that 18 F-MFBG PET/CT is an effective imaging method in the evaluation of metastatic PPGL and could be alternative of 68 Ga-DOTATATE PET/CT in this clinical setting.