Gastrointestinal tract plasmablastic lymphoma in HIV infected adults: a histopathological audit.

Abstract

Background: Plasmablastic lymphoma (PBL) is an aggressive B-cell lymphoma that is characterised by the expression of plasma cell antigens and loss of pan B-cell antigens. The neoplasm is extensively reported in the oral cavity and anorectal region but rarely in the gastrointestinal tract where only isolated case reports and small case series exist. In the current study, morphologic, immunohistochemical and molecular features of 17 cases of gastrointestinal tract PBL were reviewed. Materials and Methods: Ten-year retrospective study that reappraised the histomorphological and immunophenotypic features of HIV-associated PBLs in the gastrointestinal tract that were diagnosed and coded as ‘plasmablastic lymphoma’. Results: The average age of the study patients was 41 years with a 3:1 ratio of males to females. The most frequent site of involvement was the small intestine (42%). Majority of the cases showed a predominant diffuse (82%) growth pattern. Immunoblasts and plasmablasts were observed in all cases. Sixty-five percent (65%) of the cases exhibited scattered centroblasts and one case demonstrated predominance of centroblasts. Other features observed include pseudo-alveolar growth pattern, plasmacytic differentiation, scattered multinucleated giant cells, focal clear cell change, high mitotic activity with high proliferative indices (Ki-67 >90%), apoptotic bodies and necrosis. Immunohistochemistry revealed absence of pan B-cell antigens and expression of plasma cell antigens. Epstein-Barr virus-encoded RNA was expressed in 53% of the cases. Conclusion: This study highlights the spectrum of histopathological features of gastrointestinal tract PBLs. Additional observations not previously described or emphasised in literature includes pseudo-alveolar growth pattern, centroblast-predominance, multinucleated giant cells and clear cell change. Awareness of this entity in the gastrointestinal tract and its histopathological features and immunohistochemical profile is essential for making an accurate diagnosis and avoiding potential diagnostic errors. Keywords: Plasmablastic lymphoma; HIV-related lymphoma; AIDS-related lymphoma; gastrointestinal tract; stomach; small intestine; colon.