S4835 A Case of Plasmablastic Lymphoma Masquerading as Proctitis

Introduction: Plasmablastic lymphoma is a rare subset of lymphoma that has increased incidence in patients infected with HIV. In this vignette we present a case of recurrent rectal bleeding due to a case of plasmablastic lymphoma. Case Description/Methods: A 33-year-old man with a past medical history of HIV, syphilis, anal condyloma and positive human papillomavirus 16 presented to the hospital with recurrent rectal bleeding. Initial workup was pertinent for anemia, leukocytosis and worsened kidney function. computed tomography Imaging of the pelvis revealed an 8.0 × 7.0 cm lower rectal mass. An endoscopic evaluation with biopsy was performed which revealed an ulcerated mass in the anal canal. The pathology revealing chronic active proctitis with severe fibrinous ulceration, but no evidence of malignancy. Due to high clinical suspicion for malignancy, further biopsies were obtained through direct visualization which showed an anal condyloma with low grade dysplasia and inflammation. The bleeding was controlled through direct cauterization. The patient returned to the hospital 1 month later in acute renal failure secondary to ischemia from continued rectal blood loss. MRI at this time showed a large mass circumferentially involving the entirety of the anus and rectum. A lymph node biopsy was obtained which showed discohesive cells with a high nuclear to cytoplasmic ratio and prominent nuclei with plasmacytoid morphology. These were CD45-LCA, CD138, MUM-1, c-MYC positive and CD20 negative which is consistent with plasmablastic lymphoma. The cells also tested positive for Ebstein-Barr virus. Patient was started on the EPOCH chemotherapy regimen, which consists of etoposide, vincristine, cyclophosphamide and doxorubicin and continues to follow with oncology. He is currently tolerating treatment well. Discussion: Plasmablastic lymphoma is a rare cause of rectal bleeding, and in this case required repeated biopsy to find a definitive diagnosis. It occurs most frequently in patients with HIV or are otherwise immunosuppressed and cells are often Epstein-Barr virus positive. There is no current standard of care and EPOCH is only 1 of the chemotherapy routines that are used. In patients who are HIV positive, antiretroviral therapy is an important part of treatment.