title: Plasmablastic lymphoma in HIV+ patients: an expanding spectrum.
abstract: OBJECTIVE
  To describe an unusual human immunodeficiency virus (HIV)-associated lymphoma in uncommon sites. Plasmablastic lymphoma is a distinctive HIV-associated tumour that was first described in the jaws and oral cavity. Only two cases (stomach and lung) have been documented in extra-oral sites.
  
  
  METHODS
  Four cases were encountered in HIV+ patients: three in the anorectal region and one which was nasal and paranasal. The cases were routinely processed and immunohistochemistry was performed on formalin-fixed paraffin-embedded tissue.
  
  
  RESULTS
  The cases showed the typical morphological appearances of a high-grade, blastic non-Hodgkin's lymphoma (brisk mitotic activity and tingible body macrophages). In addition, some cells had a plasmacytoid appearance and paranuclear clearing. Immunophenotypically, the tumour cells were negative for LCA, CD20 and CD45RA. However, a small proportion of cells (5%) were immunoreactive for CD79a and the majority were positive with VS38c, indicative of plasma cell differentiation. Kappa light chain and IgG heavy chain restriction was also detected.
  
  
  CONCLUSIONS
  Plasmablastic lymphoma may occur in extra-oral sites and has a characteristic immunophenotype including focal expression of CD31 by the neoplastic cells. Awareness of the absence of expression of conventional B-cell markers and its presence in unusual sites should facilitate the diagnosis of plasmablastic lymphoma in HIV+ patients.
authors.affiliation: Department of Pathology, Nelson R Mandela School of Medicine, University of Natal, Durban, South Africa and Department of Pathology, University Health Network, Princess Margaret Hospital, Toronto, ON, Canada. runjan.chetty@uhn.on.ca
authors.forename: R
authors.initials: R
authors.lastname: Chetty
authors.forename: N
authors.initials: N
authors.lastname: Hlatswayo
authors.forename: R
authors.initials: R
authors.lastname: Muc
authors.forename: R
authors.initials: R
authors.lastname: Sabaratnam
authors.forename: K
authors.initials: K
authors.lastname: Gatter
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000032:analysis; D001005:Anus Neoplasms / Q000737:chemistry / Q000473:pathology; D014408:Biomarkers, Tumor / Q000032:analysis; D051925:CD79 Antigens; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016483:Lymphoma, AIDS-Related / Q000737:chemistry / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009669:Nose Neoplasms / Q000737:chemistry / Q000473:pathology; D010954:Plasmacytoma / Q000737:chemistry / Q000473:pathology*; D011947:Receptors, Antigen, B-Cell / Q000032:analysis
chemical_list: D015703:Antigens, CD; D014408:Biomarkers, Tumor; D051925:CD79 Antigens; C497881:CD79A protein, human; D011947:Receptors, Antigen, B-Cell