Plasmablastic Lymphoma of Small Intestine: A Rare Case Report with Review of Literature

Abstract

Plasmablastic lymphoma (PBL) is a rare aggressive neoplasm characterized by diffuse proliferation of large neoplastic cells with plasma cell immunophenotype. Cell of origin of PBL is believed to be a postgerminal center B-lymphocyte or plasmablast. The malignant cells in PBL usually do not express CD20 (B cell marker) but do express markers of plasmacytic differentiation, such as CD38, CD138, or MUM1/IRF4, akin to plasma cell myeloma (PCM). PBL though originally described in the oral cavity, has now been found to occur in extraoral locations as well. Small intestine as a site of PBL has been described very rarely. PBL remains a diagnostic challenge given its overlapping morphologic and immunophenotypic features with other high grade lymphomas and PCM. We report a rare case of PBL of small intestine in a 48 years old HIV infected male patient. To the best of our knowledge this represents sixth case in the literature described in this location. An unusual rare pattern of CD138 positivity by IHC is also reported along with extensive review of literature of PBL in extraoral locations.

Fig. 1

CECT scan of abdomen revealing circumferential diffuse wall thickening of jejunal loop and enlarged mesenteric lymph nodes

Fig. 2

A H&E stained section showing sheets of large to intermediate cells with round nuclei and small to prominent nucleoli and scanty cytoplasm (×400) B–D ×400: neoplastic cells showing membranous positivity for LCA (B); nuclear postively for MUM1 (C); cytoplasmic and perinuclear dot positively for CD138 (D); E neoplastic cells showing very high Ki67 index (90 %) (×400) F tumor cells showing positivity by EBER ISH indicating EBV infection (×400)

Fig. 3

A–F Neoplastic cells showed negative staining with CD20, CD79A, PAX5, CD10, Bcl-2, Alk1 and Bcl-6 (not shown)