PLASMABLASTIC PLASMACYTOMA OF THE RECTUM AND ANAL CANAL IN PATIENT WITH ULCERATIVE COLITIS

Aims Plasma cell tumor is a B-cell line immunoproliferative monoclonal disease. It rarely occurs in the gastrointestinal tract (GI). Our aim was to present a case of a patient with a prior history of ulcerative colitis (UC). Given its clinical presentation upon admission, the patient could easily be mistaken for disease relapse indicating the need for endoscopy along with further evaluation to establish a correct diagnosis and therefore appropriate treatment.

Methods An 88-year-old male patient was admitted to the Department for Gastroenterology for signs and symptoms suggestive of disease relapse. He was diagnosed with ulcerative colitis localized in rectosigmoid 5 years before. He reported diarrhea (approximately) 10 bowel movements/day, fecal incontinence, abdominal and backpain, weakness and weight loss. Examination revealed cahexia, tahycardia, and abdominal tenderness. We performed colonoscopy with standard tissue biopsies and immunohistochemistry which concluded extremely rare finding.

Results Colonoscopy was performed, revealing tumor-like, whitish and hard on biopsies mass located in the proximal part of the anal canal, rectum and rectosigmoid junction. Standard histopathology examination was sugestive of immunoproliferative disease requiring further evaluation. Immunochemistry revealed CD38 +, kappa +, lambda -, MUM-1 +, EBV-LMP -, CD20-, CD138-, Ki 67 + in 60% positive cells indicating plasmablastic plasmacytoma. His performance status rendered him from receiving further oncological therapy. His condition progressively worsened and he died one month after the diagnosis was established.

Conclusions Extramedullary plasmacytoma rarely affects GI tract and its occurrence in patients with UC has never been reported. Its existence could be sui generis or perhaps complicating long-standing history of inflammatory bowel disease. Nevertheless, clinicians should be aware of this rare entity even in patients with confirmed previous diagnosis affecting anorectum.