Pancreatic Follicular Lymphoma Presenting as Acute Pancreatitis: Report of a Case

Abstract

Pancreatic B-cell lymphoma is rare; it accounts for 0.2% to 2.0% of extranodal non-Hodgkin lymphoma, and constitutes less than 0.5% of all pancreatic malignancies. Most histologic types of the pancreatic lymphoma are diffuse large B-cell lymphoma, and follicular lymphoma is quite rare. We report here a case of pancreatic follicular lymphoma that was initially detected by acute pancreatitis. This is the first reported case of pancreatic follicular lymphoma presenting with acute pancreatitis. A 71-year-old woman had epigastric and left upper quadrant abdominal pain. Computed tomography (CT) revealed features of acute pancreatitis. After standard therapy for pancreatitis, enhanced CT showed a pancreatic tumor (50 × 35 mm) in the body of the pancreas with gradual enhancement. Endoscopic retrograde cholangiopancreatography and magnetic resonance cholangiopancreatography showed a complete interruption of the pancreatic duct in the body, with mild dilation of the duct in the tail of the pancreas. Endoscopic ultrasonography revealed hypervascularity of the pancreatic tumor. The patient underwent distal pancreatectomy to remove the cause of pancreatitis and to disclose the diagnosis. Histologic examination revealed follicular lymphoma of pancreas. Despite recent improvement in clinical strategies, differential diagnosis between pancreatic lymphoma and pancreatic cancer is still difficult without histologic information. Pancreatic lymphoma should be considered as a differential diagnosis in a patient who initially presents with acute pancreatitis.

Keywords: Acute pancreatitis; Follicular lymphoma; Pancreatic lymphoma.

Fig. 1

Abdominal plain CT revealed edema around the tail of the pancreas and a cloudy fat density in the anterior pararenal space.

Fig. 2

Enhanced CT showed a tumor in the body of the pancreas with delayed contrast enhancement. (A) Arterial phase. (B) Portal phase. (C) Venous phase.

Fig. 3

Magnetic resonance imaging revealed a tumor (arrows) with low intensity on T1-weighted images with fat suppression (A), with isointensity on T2-weighted images (B), with high intensity on diffusion magnified-weight imaging (C), and with isointensity on apparent diffusion coefficient mapping (D).

Fig. 4

ERCP (A) and magnetic resonance cholangiopancreatography (B) showed complete interruption (arrows) of the pancreatic duct in the body of the pancreas.

Fig. 5

EUS disclosed a hypoechoic mass in the body of the pancreas with hypervascularity of the tumor (arrow).

Fig. 6

(A) Microscopic examination following hematoxylin-eosin staining, which showed acute pancreatitis with lymphocyte-infiltrating parenchyma of the pancreas tail. (B) Hematoxylin-eosin staining, which demonstrated follicular-type lymphoma cells. (C) Lymphoma cells involving the parenchyma of the exocrine pancreas and Langerhans islets. Both CD79a immunostaining (D) and bcl-2 immunostaining (E) are positive.