1416 Rare Presentation of Large Pancreatic Mass With Chylous Ascites

Abstract

INTRODUCTION: Primary pancreatic lymphomas (PPL) are very rare and mimic pancreatic head cancer. We present a case of a man who presented with a pancreatic mass and chylous ascites, and was found to have PPL. CASE DESCRIPTION/METHODS: A 69-year-old man presented with 2 months of anorexia, abdominal pain and distension. He denied fever, chills or weight loss. Abdomen was distended, soft, non-tender with shifting dullness and fluid thrill. Laboratory tests were noncontributory except for mildly elevated LDH 254 U/L. Abdominal computed tomography (CT) showed a 20 × 10 × 17 cm soft tissue mass impinging the distal duodenum, replacing the proximal pancreatic parenchyma, encasing the celiac and superior mesenteric arteries; ascites, lymphadenopathy and multiple omental nodules were seen. No cirrhosis or hepatomegaly noted. 2.5 L of grossly chylous fluid was drained with lymphocytic predominance, high triglycerides 980 mg/dL and negative cytology. Endoscopic ultrasound (EUS) showed an irregular hypoechoic mass. Fine needle aspiration (FNA) showed lymphoid cells with irregular nuclear membrane contours strongly positive for CD20, consistent with B cell lymphoma. PET-CT scan confirmed a metabolically active pancreatic mass with inguinal, aortocaval, juxtadiaphrgamatic and inframammary lymphadenopathy. Diagnostic laparoscopic biopsy confirmed diffuse B-cell lymphoma of germinal center origin positive for CD10, BCL6, BCL2 and CD45. Patient received 6 cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone) which he tolerated well. Follow-up PET CT scan showed reduction in size of pancreatic mass and lymph nodes without areas of new/worsening lymphoma. DISCUSSION: PPLs comprise 0.5% of all pancreatic masses. Diagnostic criteria include dominant pancreatic mass, without superficial or mediastinal lymphadenopathy, absent hepatosplenic involvement and a normal blood leukocyte count. Clinical presentation is non-specific without classic symptoms of nodal lymphoma. Abdominal pain is the most common symptom (83%), followed by abdominal mass and weight loss. High tumor burden, β2-microglobulin levels >2 mg/l and high LDH levels are poor prognostic markers. Definitive diagnosis requires histologic confirmation, EUS-guided sampling is highly accurate. Treatment options include surgery, chemotherapy, radiation, alone or in combination. Cure rates upto 30% have been reported. Long term remission can be obtained with CHOP chemotherapy alone in majority of patients. Addition of rituximab results in overall improvement in patient survival.