S1686 Primary Pancreatic Diffuse Large B Cell Lymphoma: A Rare and TreaTable Malignancy

Abstract

Introduction: Pancreatic lymphoma comprise less than 1 % of pancreatic malignancies. Most common location of diffuse large B cell lymphoma (DLBCL) are lymph nodes. Clinical symptoms and imaging studies have significant similarity resulting in delayed diagnosis or early initiation of comfort care measures. It is important to determine the histology of pancreatic tumor given the differences in management and prognosis. Here we report a rare case of primary DLBCL arising from pancreas. Case Description/Methods: 62-year-old female with history of HTN and DM presented with 30 lbs unintentional weight loss epigastric abdominal pain and early satiety. CT abdomen with IV and oral contrast demonstrated pancreatic mass. Core biopsy of pancreatic head mass demonstrated infiltration by large atypical lymphoid cells with high N/C ratio, round nuclear contour, fine chromatin and variably prominent nucleoli (Figure A). Atypical mitosis and apoptosis seen in background. Lymphoma cells positive for CD 19, CD 20 (Figure B). Final diagnosis Large B cell lymphoma germinal center type. FISH for BCL 2, C MYC were normal ruling out possibility of double or triple hit lymphoma. Cancer antigen 19-9 at the time of diagnosis was within normal limits. FDG PET/CT prior to initiation of treatment showed main foci of increased tracer activity appears to be in the proximal body of the pancreas just medial to the stomach, measures greater than 4 cm in diameter, and has a maximum SUV of 11.86 (Figure C). Rituximab- Cyclophosphamide HydrOxyadriamycin Prednisone (R-CHOP) every 3 weeks initiated. After one cycle of R-CHOP reported significant improvement in epigastric pain and started gaining weight. She completed 6 cycles of R-CHOP. Post treatment FDG PET/CT complete resolution of upper abdominal lymph node mass (Figure D). She remains in remission for the past 1 year. Discussion: Our case is an example of successful biopsy and treatment with aim to cure pancreatic malignancy. Despite radiological differences between pancreas adenocarcinoma and lymphoma, it is crucial to obtain adequate tissue sampling during from pancreas to establish histological diagnosis prior to discussion of prognosis and treatment plan. In general, DLBCL germinal center type has a 5-year survival of 70% with R-CHOP. Differential diagnosis of pancreatic mass that confer better prognosis than adenocarcinoma include neuroendocrine tumor, solid pseudopapillary tumor and lymphoma. Therefore, it is important to obtain biopsy and direct therapy based on histology.Figure 1.: A: Core biopsy of pancreatic head mass demonstrated infiltration by large atypical lymphoid cells with high N/C ratio, round nuclear contour, fine chromatin and variably prominent nucleoli. B: Lymphoma cells positive for CD 19, CD 20. C: FDG PET/CT prior to initiation of treatment showed main foci of increased tracer activity appears to be in the proximal body of the pancreas just medial to the stomach, measures greater than 4 cm in diameter, and has a maximum SUV of 11.86. D: Post treatment FDG PET/CT complete resolution of upper abdominal lymph node mass.