A Rare Case of Primary B-Cell Lymphoma of the Pancreas

Abstract

Primary pancreatic lymphomas (PPLs) are a subgroup of gastrointestinal (GI) lymphomas. They are an exceedingly rare entity, both in terms of pancreatic malignancies and also extranodal lymphomas. Epidemiological investigations have been challenging to do because of their rarity. This has resulted in a lack of clarity on the clinicopathological characteristics, differential diagnosis, best course of treatment, and prognosis of PPL. Because the clinical signs are frequently non-specific, it can lead to a diagnostic hazard for the unwary physician. Preoperatively, it is imperative to distinguish between adenocarcinoma and PPL, as they present similarly, but have vastly different treatment modalities and prognosis. We herein present a case of an elderly man who presented with obstructive jaundice and was found to have PPL.

Introduction

Primary pancreatic lymphomas (PPLs) are a subgroup of gastrointestinal (GI) lymphomas. They amount for 0.16% to 4.9% of all pancreatic malignancies ¹ which makes them a very rare entity. Recently, great efforts have been made to distinguish PPL from adenocarcinoma as it has shown excellent response to chemotherapy hence avoiding the need for surgery. ²

We herein present a case of an elderly man who presented with obstructive jaundice and was found to have primary pancreatic lymphoma.

Case Summary

A 71-year-old male patient with a past medical of gastroesophageal reflux disease and hyperlipidemia presented to our hospital with jaundice and evidence of common bile duct (CBD) dilation with gallbladder wall thickening on abdominal ultrasound performed as outpatient. His symptoms also included abdominal bloating and decreased appetite. He had noted a 6 kg unintentional weight loss over the last 3 weeks. In addition, he was complaining of dark urine and clay colored stool. There was no addition of any new medications, and he was not taking any herbal remedies. Labs upon presentation were significant for elevated alanine transaminase (ALT) 300 U/L, aspartate transaminase (AST) 200 U/L, and alkaline phosphatase 652 U/L. Serum total bilirubin and direct bilirubin were elevated at 2.7 and 1.7 mg/dL, respectively. Magnetic resonance cholangio pancreatography (MRCP) was obtained which showed CBD dilation to 14 mm with no evidence of choledocholithiasis (Figure 1). A pancreatic mass was noted with evidence of mesenteric and left periaortic lymphadenopathy. A computed tomography (CT) of the abdomen with pancreatic mass protocol obtained as a follow-up imaging showed the presence of a 4 cm pancreatic head mass obstructing the CBD with encasement of the portal vein confluence and superior mesenteric artery (Figures 2 and 3). An endoscopic ultrasound (EUS) with fine-needle aspiration (FNA) was performed. Pathology revealed evidence of hypercellular, atypical lymphoid cells (Figure 4) which were CD-45 positive (Figure 5) on immunohistochemistry. The patient was referred to hematology/oncology for treatment. Endoscopic retrograde cholangio pancreatography (ERCP) was not feasible due to duodenal stenosis and the patient underwent IR-guided percutaneous biliary drain placement. The patient was lost to follow-up, and we are unsure if they pursued any chemotherapeutic modalities.

Figure 1.

Coronal plane MRCP image demonstrates a dilated common bile duct (arrow) with abrupt tapering of the distal most portion.

Figure 2.

Coronal plane image from a CT abdomen and pelvis with IV and oral contrast demonstrates a dilated common bile duct (arrow) and a large pancreatic head mass inferior to the distal duct.

Figure 3.

Axial plane image from a CT abdomen and pelvis with IV and oral contrast shows a large pancreatic head mass (arrow).

Figure 4.

Hypercellular atypical lymphoid cells—high power ×40.

Figure 5.

CD-45 positive on IHC—high power ×40.

Discussion

Multiple criteria have been proposed for the diagnosis of PPL. Diagnostic criteria to identify PPL were initially recognized by Dawson et al and were later modified by Behrns et al. ³ These characteristics included the following: (1) no palpable superficial lymphadenopathy; (2) no enlargement of mediastinal lymph nodes on chest radiograph; (3) normal leukocyte count; (4) at celiotomy, or more commonly known as laparotomy, the pancreatic mass predominates with grossly involved lymph nodes confined to the peripancreatic region; and (5) no hepatic or splenic involvement.^3,4 The most recent definition was provided in 2011 by the World Health Organization (WHO) and reaffirms the above. ⁵

Primary pancreatic lymphoma can develop at any age but most commonly present in elderly patients with male predominance. Immunosuppression is believed to be a predisposing risk factor. ⁶ Clinically, the most common presenting symptom is abdominal pain, but other non-specific symptoms can also be associated with PPL which include fever, chills, weight loss, jaundice, and gastric/small bowel obstruction. ⁷ The first step in the diagnosis is obtaining abdominal imaging. Abdominal ultrasonography (US), EUS, CT, or MR abdomen with and without intravenous (IV) contrast under pancreatic mass protocol are all reliable studies to evaluate pancreatic masses. Confirmation of diagnosis requires histopathologic sampling. Although CT-guided FNA may be performed, EUS-guided tissue sampling of the pancreatic lesion is generally considered to be a superior modality. ⁸ Most PPLs are diffuse large B-cell lymphomas (DLBCL) in adults and, in children, Burkitt lymphoma (BL). ⁹ However, follicular variants and T-cell subtypes have also been reported. ¹⁰

When a pancreatic mass is detected, it is critical to differentiate it from an adenocarcinoma because this will impact treatment options and results. Most solid masses in the pancreas are ductal adenocarcinomas, which are treated surgically if deemed resectable. Radiation therapy, chemotherapy, surgery, or a combination of these is the available treatments for PPL. For patients of all ages, 6 to 8 cycles of anthracycline-based chemotherapy such as R-CHOP is part of the conventional treatment for non-Hodgkin’s lymphoma. Standard chemotherapy usually works well for high-grade pancreatic lymphoma, and it can be used alone to achieve long-term disease remission. ¹¹ Primary pancreatic lymphoma patients have a 30% cure rate according to comprehensive treatment approaches ¹² ; this is a better prognosis than the pitiful 5% 5-year survival rate for pancreatic adenocarcinoma patients. ¹³

In conclusion, PPL are a rare subtype of extranodal lymphomas that can have a presentation similar to pancreatic adenocarcinoma. Histopathologic sampling is needed for diagnosis. It is important to differentiate between pancreatic adenocarcinomas and PPL as the latter is responsive to chemotherapy and rarely require surgical intervention.