Ga-68 DOTATATE PET/CT demonstrating uptake in vertebral hemangioma mimicking osseous metastasis from pancreatic neuroendocrine tumor.

Introduction: Ga-68-DOTATATE PET/CT is considered a standard part of staging well-differentiated neuroendocrine tumor of the pancreas, recently replacing In-111 pentetreotide SPECT/CT in this role. Uptake is not entirely specific, with various unrelated and benign entities occasionally demonstrating uptake and confounding diagnosis. A small number of reports indicate that vertebral hemangiomas can demonstrate uptake and may mimic osteolytic metastasis, altering both stage and management of disease. Methods/Results: We present a case of a 58 year old female with an arterially enhancing mass in the pancreatic head on contrast enhanced CT and subsequently diagnosed with neuroendocrine tumor of pancreas by EUS-guided FNA. Staging Ga-68-DOTATATE PET/CT demonstrated significant uptake in the pancreatic head mass (SUV max of 16.5) and mild uptake in a T8 vertebral lucent lesion (SUV max of 2.2), the latter reported as possible metastasis on the basis of abnormal uptake and lytic appearance on the nondiagnostic CT images. Contrast enhanced MRI of the spine reported high T2 and low T1 signal and enhancement in the T8 lesion, suspicious for metastasis, although an atypical hemangioma can have the same appearance. CT of the spine demonstrated a definitive appearance of hemangioma for the T8 lesion on axial CT with a “polka-dotted” appearance, though with a somewhat atypical thin sclerotic rim and absence of a well-defined “corduroy sign” on sagittal CT. Nonetheless, because of the CT appearance, a hemangioma was felt very likely to be the etiology. Definitive therapy with Whipple procedure was undertaken. On follow up about 2.5 years later, the patient was asymptomatic, chromogranin A was within normal range, and there was no evidence of disease per reports from outside imaging.

Conclusions: The reader should be aware that lucent/lytic bone lesions with Ga-68-DOTATATE uptake on low-resolution CT performed with PET imaging may represent a vertebral hemangioma as opposed to metastasis, as this can impact staging and management. This has been described sporadically in the European literature. There has not been a case of In-111 pentetreotide uptake in vertebral hemangioma, perhaps due to limitations of spatial resolution of SPECT imaging or to a different uptake mechanism in hemangiomas compared to Ga-68-DOTATATE.

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