Extranodal Involvement of the Anorectal Region in an HIV-Positive Patient With Plasmablastic Lymphoma: A Case Report.

Plasmablastic lymphoma (PbL) is a rare type of aggressive B-cell malignancy that has an extremely poor prognosis without chemotherapeutic treatment, requiring a high degree of suspicion for an early and accurate diagnosis. It has been classically described in patients infected with the human immunodeficiency virus (HIV). However, it accounts for only 2.6% of acquired immunodeficiency syndrome (AIDS)-related lymphomas. Extranodal involvement is most commonly seen within the oral cavity (44%). Involvement of the gastrointestinal tract (14%) is rare and can often be confused with other malignancies with plasmablastic features. We present a rare case of PbL in a 55-year-old male with HIV-AIDS (CD4 (cluster of differentiation 4) cell count of 128), who presented for evaluation of incidentally detected multiple liver masses and lytic lesions in the ribs. Further workup revealed evidence of a lesion with increased uptake in the anorectal region with fine needle aspiration (FNA) biopsy identifying the lesion as plasmablastic lymphoma.