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We present a case of intrabiliary primary B-cell lymphoma masked as a cholangiocarcinoma in an HIV-positive patient. The two entities have similar symptoms, laboratory findings, and imaging findings but require very different treatments. The case highlights the need to confirm the diagnosis by biopsy.
HIV-associated primary non-Hodgkin's lymphoma of the bile duct is an uncommon presentation of obstructive jaundice, with few published cases (1). With similar symptoms and laboratory and imaging findings, bile duct lymphoma and cholangiocarcinoma can be almost identical (2). Since cholangiocarcinoma is far more prevalent than primary bile duct lymphoma, a presumed diagnosis of cholangiocarcinoma is often made before biopsy confirmation (3)—an approach that raises concern since the two malignancies require radically different treatment.
A 61-year-old HIV-infected man with a CD4 count of 77 mL presented to the emergency department with nausea, vomiting, epigastric pain, jaundice, and pruritus. He also reported dark urine and light-colored stools. Laboratory workup was consistent with obstructive jaundice. Magnetic resonance imaging of the abdomen showed intrahepatic and extrahepatic biliary dilation and an abnormal enhancement at the bifurcation of the common hepatic duct, suggestive of cholangiocarcinoma (Klatskin tumor) (Figure 1). Endoscopic retrograde cholangiopancreatography demonstrated nodular, erythematous walls and high-grade bile duct stricture. He underwent sphincterotomy and stenting. Biopsy of the bile duct was positive for CD20, BCL-2, BCL-6, two-paired box protein Pax-5, CD10, and B-cell lymphoma 6 protein, with antigen Ki-67 demonstrating >90% confirmation of high-grade large B-cell lymphoma (Figure 2). Immunoperoxidase stains for c-Myc demonstrated staining in >30% of the cells. Positron emission tomography–computed tomography showed hypermetabolic activity in the area of the hilar bile duct without metastatic disease. Pretreatment evaluation is under way, with plans to initiate rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy.
Non-Hodgkin's lymphoma resulting in obstructive jaundice is primarily caused by extrahepatic lymphoma compressing the bile duct, causing a mass effect. Very rarely is obstructive jaundice due to primary bile duct lymphoma, as in this vignette (4). On imaging, intra- and extrahepatic bile duct dilation was noted. Essentially identical radiologic findings may be found in the setting of cholangiocarcinoma.
Adequate biopsy is needed for definitive diagnosis, as the management and prognosis for cholangiocarcinoma and lymphoma are notably different (5). Treatment for cholangiocarcinoma is surgical resection or gemcitabine-based chemotherapy. Lymphoma is more chemoresponsive, and management utilizes the R-CHOP regimen. In addition, a diagnosis of lymphoma carries a better overall prognosis than cholangiocarcinoma. Biliary obstruction in the setting of lymphoma correlates with advanced disease, only emphasizing the importance of rapid diagnosis and initiation of correct treatment. As lymphoma is an AIDS-defining illness, its diagnosis in an HIV-infected patient is not only important for initiation of appropriate treatment but also serves a prognostic purpose. The diagnosis indicates an immunocompromised state, regardless of CD4 count, and the need for careful oversight of the patient's overall management.