S1618 Finding the Needle in the Haystack: PTLD Occurring in the Background of GVHD and Infection

Abstract

INTRODUCTION: Post-transplant lymphoproliferative disorder (PTLD) is an uncommon complication after hematopoietic stem cell transplant and is associated with Epstein-Barr virus infection and more aggressive immunosuppressive regimens. PTLD can coincide with graft versus host disease (GVHD) and mimic other disorders making endoscopic tissue sampling central to diagnosis and treatment. CASE DESCRIPTION/METHODS: A 27-year-old male was admitted for worsening diarrhea after undergoing umbilical cord blood transplant for Blastic plasmacytoid dendritric cell neoplasm 5 months prior. His transplant course was complicated by several hospitalizations for GVHD of the gut. A colonoscopy 4 months earlier was endoscopically normal with biopsies consistent with GVHD (Figure 1). At this time, the patient presented with 10 days of non-bloody diarrhea in the setting of tapering prednisone dose, similar to prior flares of GVHD. He reported mild chronic abdominal pain but was otherwise asymptomatic. Flexible sigmoidoscopy showed deep linear ulcerations from the proximal rectum to the sigmoid colon with edema, friability, and loss of vascular pattern (Figure 2) which were biopsied. GI PCR returned positive for salmonella and C difficile. A few days later he developed massive hematochezia necessitating ICU level care and massive blood transfusion protocol. Repeat colonoscopy showed interval progression of ulcerations with diffuse bleeding. Biopsies from original flexible sigmoidoscopy showed CD20/EBV + immunoblasts with intermixed CD3+ T cells and polytypic plasma cells (Figure 3) and serum EBV viral load was elevated confirming the diagnosis of PTLD. Patient was started on rituximab and achieved negative viremia after 8 weeks though his course was complicated by recurrent hematochezia. DISCUSSION: The gastrointestinal tract is a common site for PTLD. As patients can present with nonspecific symptoms and confounding diagnoses, identification requires a high index of suspicion. Endoscopic diagnosis through biopsy is critical given the associated high mortality. The characteristic lesion of PTLD in the gastrointestinal tract has been described as a raised, rubbery and erythematous lesion with central ulceration. Although this patient did not have the classic endoscopic finding and had several competing GI diagnoses, he had several risk factors for developing PTLD and once diagnosed responded appropriately to therapy.Figure 1.: First colonoscopy after umbilical cord transplant showed normal endoscopic appearance, random colonic biopsies were consistent with GVHD.Figure 2.: Subsequent flexible sigmoidoscopy showed deep linear ulcerations with edematous mucosa, friability, and loss of vascular pattern in the sigmoid colon just four months later.Figure 3.: H&E stain; 40× field: Atypical lymphoid proliferation as exhibited by numerous large, irregular immunoblasts with prominent nucleoli (examples: black arrows).