Rare-Site Primary Presacral-Precoccygeal Grade III Neuroendocrine Tumor with Bilobar Hepatic Involvement: A Case Description with Diagnostic and Therapeutic Considerations

Abstract

Primary presacral/precoccygeal neuroendocrine tumors (NETs) are extremely uncommon, however, can present with widespread metastases. We herein report the imaging and therapeutic perspectives in a 45-year-old female patient of presacral-precoccygeal NET who presented with low back pain. Magnetic resonance imaging of the lumbosacral spine showed a soft tissue mass in the presacral region extending into the S1–S2 neural foramen, along with another soft tissue mass in the precoccygeal region. Incidentally, multiple well-defined lobulated hyperintense lesions were detected in both lobes of the liver. ¹⁸F-FDG PET/CT (¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography) demonstrated tracer accumulation in the primary soft tissue masses in the presacral and precoccygeal regions, while the liver lesions did not show significant tracer uptake. A CT-guided biopsy of the presacral mass confirmed a well-differentiated NET, Grade III, with a Ki-67 index of 20 to 22%. ⁶⁸Ga-DOTATATE PET/CT revealed somatostatin receptor expression in the presacral and precoccygeal masses, as well as in the bilobar liver lesions. Due to the tumor's presentation with widespread metastases, surgery was deemed inappropriate, and peptide receptor radionuclide therapy was planned.

Keywords

neuroendocrine tumors - presacral-precoccygeal grade III NET - ¹⁷⁷Lu-DOTATATE - ⁶⁸Ga-DOTATATE PET/CT - ¹⁸F-FDG PET/CT - bilobar liver metastasis - peptide receptor radionuclide therapy (PRRT) - PET/CT

Publication History

Article published online:
21 July 2025

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