Focal Pancreatitis Mimicking Neuroendocrine Tumor on DOTATATE PET/CT With Radiology-Pathology Correlation

Area of Science:

• Gastroenterology and Hepatology
• Diagnostic Imaging
• Endocrinology

Background:

• Neuroendocrine tumors (NETs) are neoplasms arising from neuroendocrine cells, often presenting incidentally.
• Advanced imaging modalities like MRI and PET/CT are crucial for diagnosing pancreatic lesions.
• DOTATATE PET/CT is highly sensitive for well-differentiated NETs.

Observation:

• A 54-year-old man with left lower quadrant pain had an incidental 2.0-cm pancreatic tail lesion.
• The lesion showed hyperenhancement and diffusion restriction on MRI, suspicious for NET.
• Endoscopic ultrasound (EUS)-guided biopsy revealed benign pancreatic tissue, creating diagnostic discordance.

Findings:

• 64Cu-DOTATATE PET/CT demonstrated significant tracer avidity in the pancreatic tail lesion.
• This finding further suggested a well-differentiated neuroendocrine tumor.
• Surgical pathology after distal pancreatectomy revealed focal chronic pancreatitis with islet aggregation, not a NET.

Implications:

• Focal chronic pancreatitis with islet aggregation can mimic a neuroendocrine tumor on DOTATATE PET/CT.
• This case underscores the need for careful clinicoradiological correlation and consideration of rare mimics.
• It highlights a previously undescribed entity that can lead to overdiagnosis of NETs.