They occur predominantly in males who have HIV/AIDS, had a solid organ transplant, or are immunosuppressed in other ways; ~5% of all individuals with PBL appear to be immunocompetent, i.e. to have no apparent defect in their immune system. The malignant plasmablasts in more than half the cases of PBL are infected with a potentially cancer-causing virus, Epstein–Barr virus (EBV), and rare cases of PBL appear due to the  plasmablastic transformation of a preexisting low-grade B-cell lymphoma. One variant of PBL, sometimes termed plasmablastic lymphoma of the elderly, has a significantly better prognosis than most other cases of PBL. The development of this variant appears due, at least in part, to immunosenescence, i.e. the immunodeficiency occurring in old age. Presentation
Plasmablastic lymphoma lesions are most commonly rapidly growing, soft tissue masses that may be ulcerating, bleeding, and/or painful. In a recent (2020) review of published cases, individuals presenting with PBD were typically middle-aged or elderly (range 1–88 years; median age 58 tears) males (~73% of cases). Only a few cases have been reported in pediatric cases. The PDL lesions occurred most commonly in lymph nodes (~23% of cases), the gastrointestinal tract (~18%), bone marrow (16%), and oral cavity (12%). Less frequently involved tissues include the skin, genitourinary tract, paranasal sinuses, lung, and bones.
First arch syndromes are congenital defects caused by a failure of neural crest cells to migrate into the first pharyngeal arch. They can produce facial anomalies. Examples of first arch syndromes include Treacher Collins syndrome and Pierre Robin syndrome. == References ==