Primary Pancreatic Extra-Nodal Natural Killer T-Cell Lymphoma Presenting as Recurrent Acute Pancreatitis

CASE REPORT A 45-year-old woman presented with recurrent acute pancreatitis. Magnetic resonance imaging showed a 4.7 cm mass in the pancreatic head and 10 mm common bile duct dilation (Figure 1). Hepatic function panel revealed aspartate aminotransferase 129, alanine aminotransferase 177, alkaline phosphatase 186, total bilirubin 2.5, and direct bilirubin of 1.9 mg/dL secondary to the extrinsic compression of the common bile duct.Figure 1.: (A) 4.7 cm mass in the pancreatic head (arrow) and 10 mm common bile duct dilation on magnetic resonance imaging of the abdomen. (B) Endoscopic ultrasound with arrow showing a diffusely bulky pancreas without a discrete mass.Endoscopic ultrasound showed a diffusely bulky pancreas without discrete mass (Figure 1). Cytology from fine needle biopsy from the head of the pancreas revealed a lymphocytic infiltrate of T-cell predominance. Endoscopic retrograde cholangiopancreatography brushings were negative for malignancy. Immunostaining was consistent with Epstein-Barr virus-positive T-cell proliferation, concerning for lymphoma. Computed tomography-guided pancreatic biopsy (Figure 2) showed atypical lymphoid infiltrate that was CD3 and Epstein-Barr Encoded RNA positive, confirming the diagnosis of extra-nodal natural-killer/T-cell lymphoma, an aggressive form of non-Hodgkin lymphoma often secondary to Epstein-Barr virus infection.1 The patient was started on modified SMILE chemotherapy (dexamethasone, methotrexate, ifosfamide, L-asparaginase and etoposide).Figure 2.: Involvement of pancreas and central nervous system by Epstein-Barr virus-positive T-cell lymphoma. Hematoxylin and eosin stained slides (20×) demonstrate residual glandular pancreas (A and D) involved by a dense lymphocytic infiltrate by CD3-positive T-cells (B and E) with variable degrees of EBER positivity (C and F). The top panels depict the original cytology specimen, which shows minimal involvement by the atypical lymphoid infiltrate with intact residual glandular and ductal pancreatic tissue; the bottom panels depict the subsequent diagnostic core needle biopsies demonstrating diffuse involvement by the extranodal CD3+/EBER+ T-cell lymphoma.Natural-killer/T-cell lymphoma is most observed in the nasopharynx and is rare in the gastrointestinal tract, particularly in the pancreas.2,3 It remains a challenging diagnosis due to atypical features and often mimics more common pancreatic diseases. The diagnosis of malignancy should always be considered when there is no obvious etiology for pancreatitis.4 DISCLOSURES Author contributions: C. Blumrosen and N. Mitchell: Study concept, design, and drafting of manuscript. C. Syposs: histopathology figure design. T. Kothari: Critical review and approval of final manuscript and is the article guarantor. Financial disclosure: The authors declare that this work was conducted in the absence of commercial, financial or non-financial relationships that could be interpreted as a potential conflict of interest. Previous presentation: Presented at The American College of Gastroenterology Annual Meeting in Philadelphia, PA on 10/27/2024. Informed consent was obtained for this case report.