Intravascular large B-cell lymphoma manifesting as cholecystitis: report of an Asian variant showing gain of chromosome 18 with concurrent deletion of chromosome 6q.

Intravascular large B-cell lymphoma (IVLBCL), which involves the lumen of small vessels, is a rare variant of extranodal diffuse large B-cell lymphomas. Herein, we present a case of IVLBCL manifesting as cholecystitis in a 77-year-old Japanese man. He presented with fever, fatigue, and weight loss. Physical examination revealed tenderness of the right upper quadrant. The white blood cell count and C-reactive protein levels were elevated. Computed tomography revealed gallbladder thickening and pericholecystic fluid collection; these observations were consistent with the diagnosis of cholecystitis. Serum soluble interleukin-2 receptor levels were highly elevated, and gallium scintigraphy revealed an abnormal accumulation in the spleen, implying lymphoma. Consequently, G-banding analysis of the patient's bone marrow aspirates revealed the presence of different abnormal clones, including those with gain of chromosome 18 and deletion of chromosome 6q. As cholecystectomy was necessary, a concurrent splenectomy was performed to diagnose the disease definitively. Histopathologically, atypical large lymphoid cells were observed to be localized in the vasculature in both the spleen and gallbladder; the atypical cells expressed high levels of CD20, CD5, and CD10, immunohistochemically. These findings were consistent with IVLBCL. The patient underwent post-operative treatment with rituximab, cyclophosphamide, adriamycin, vincristine, and prednisolone. However, a pancreatic fistula developed during chemotherapy, causing left pleural effusion and peritoneal effusion; the patient developed sepsis from multidrug-resistant microorganisms, and subsequently died of multi-organ failure 6 months after the diagnosis. No obvious recurrence of the tumor was found during autopsy. We discuss the characteristic karyotype and immunohistochemical status observed in this case.