S3479 Chicken or Egg? The Paradox of a Large Pancreatic Lymphoma with Systemic Spread

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is the most common pancreatic malignancy. Anaplastic T-cell lymphoma (ALCL) is another, much rarer tumor that has different management and prognosis. Here, we present a rare case of ALCL of the pancreatic head. Case Description/Methods: An 81-year-old man presented to the emergency department with a 3-week history of dull epigastric pain and nausea. Physical examination revealed normal vital signs, abdominal tenderness, and multiple palpable subcutaneous nodules with overlying erythema on the left chest and back. Laboratory tests showed a lipase of 700 U/L, ALT of 138 U/L, AST of 157 U/L, bilirubin of 2.2 mg/dL, and ALP of 206 U/L. Carbohydrate antigen 19-9 level was high at 84.8 U/mL. Computed tomography showed widespread lymphadenopathy and a 5 × 4 cm mass of the head/uncinate process resulting in upstream biliary ductal dilation. En doscopic retrograde cholangiopancreatography showed a main bile duct malignant stricture with upstream dilation. A biliary sphincterotomy was performed with subsequent placement of a covered metal stent. The ampulla appeared normal without surrounding masses. Endoscopic ultrasound showed a heterogeneous, hypoechoic pancreatic head mass with irregular borders. Fine-needle aspiration (FNA) revealed ALCL staining positive for CD30 and negative for anaplastic lymphoma kinase (ALK). He was offered chemotherapy, but he opted for hospice care at home. Discussion: Pancreatic lymphoma (PL) can be primary (PPL), originating in the pancreas, or secondary (SPL), due to metastasis from a distant source. The distinction between the 2 is based on clinical and radiologic criteria, as their pathological features are identical. A pancreatic mass with peripancreatic lymphadenopathy, in the absence of superficial or mediastinal lymph node involvement, hepatic lesions, or splenic infiltration, is highly suggestive of PPL. The wide subcutaneous, multi-organ, and lymphatic spread in our case favors SPL, which is most commonly from a nodal source. Notably, the large size of his pancreatic mass is not typical of secondary dissemination. The patient chose hospice care, limiting further evaluation to unravel the primary source. Unlike the management of PDAC, which relies on curative resection, ALCL is treated with chemotherapy and carries a better prognosis. The identification of ALK helps stratify ALCL into ALK-positive and ALK-negative tumors. The former has a favorable prognosis due to the potential for targeted therapy.