Idiopathic Non-Caseating Granulomatous Lesion of the Pancreas Mimicking a Neuroendocrine Tumor: A Diagnostic Challenge.

Pancreatic granulomas are uncommon and typically classified based on the presence or absence of caseation. Caseating granulomas are most often associated with tuberculosis, while non-caseating granulomas are usually secondary to systemic conditions such as sarcoidosis. Idiopathic cases are rare and can pose a significant diagnostic challenge, particularly when mimicking malignancy. We present a unique case initially suspected to be a neuroendocrine tumor, ultimately diagnosed as an idiopathic non-caseating pancreatic granuloma.

A 75-year-old female was evaluated for left upper quadrant abdominal discomfort accompanied by chronic diarrhea and intermittent palpitations. Initial laboratory studies were notable for a markedly elevated chromogranin A level of 3123 ng/mL, with normal urinary metanephrine levels Cross-sectional imaging with magnetic resonance imaging demonstrated a 2.5-cm cystic lesion communicating with the main pancreatic duct and an additional hypointense lesion involving the pancreatic tail. Despite clinical concern for a neuroendocrine neoplasm, ^68Ga-DOTATATE PET/CT demonstrated no radiotracer uptake within the pancreatic lesion. Subsequent endoscopic ultrasound revealed a 2.7-cm well-defined, homogeneous hypoechoic pancreatic mass with multiple enlarged peripancreatic lymph nodes. Cytologic examination of fine-needle aspiration specimens showed non-caseating granulomatous inflammation in the setting of otherwise benign pancreatic and lymphoid tissue. Comprehensive evaluation failed to identify an underlying infectious, inflammatory, or systemic cause, supporting the diagnosis of an idiopathic non-caseating pancreatic granuloma.

Non-caseating granulomas of the pancreas are rare, with sarcoidosis being the most frequently reported cause. Clinical presentation may include epigastric pain, weight loss, jaundice, fever, or nausea. Due to the potential overlap with malignancies, comprehensive diagnostic workup-including imaging, tissue sampling, and occasionally surgical intervention-is essential for accurate diagnosis and management.

Idiopathic non-caseating pancreatic granuloma is an exceptionally rare entity. A timely and thorough evaluation is critical to exclude malignancy and ensure appropriate patient management.
Cancer
Care/Management

Authors

AlBarakat AlBarakat, Althunibat Althunibat, Altawalbeh Altawalbeh, Hasan Hasan, Abdel-Jalil Abdel-Jalil
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