Adenoviral Subacute Focal Meningoencephalitis Complicating Polatuzumab, Bendamustine and Rituximab Chemo-Immunotherapy for Aggressive B-Cell Lymphoma.

Polatuzumab, Bendamustine and Rituximab (Pola-BR) are a newly approved therapy regime for refractory Diffuse Large B cell Lymphoma (DLBCL). We describe an unusual case of Adenovirus Encephalitis following this therapy. A 55-year-old male presented in 2017 with an enlarging subcutaneous paravertebral mass and a biopsy revealed c-myc negative Diffuse Large B-Cell Lymphoma (DLBCL, Stage IVB). The patient was commenced on 6 cycles of Rituximab, Cyclophosphamide, Doxorubicin, Vincristine, Prednisolone (R-CHOP) and Methotrexate achieving a complete response (CR). In 2019, he relapsed and was commenced on Rituximab, Gemcitabine and Cisplatin salvage therapy. Repeat PET-CT illustrated stable disease, however he deteriorated in his performance status. Disease progression occurred on Carmustine, Etoposide, Cytrabine, Melphalan (mini-BEAM) therapy. The patient then achieved remission with second-line 6 cycle salvage PolaBR. He received Aciclovir prophylaxis during his treatment. The patient clinically deteriorated requiring admission in 2020 with delirium and worsening pyrexia despite prolonged broad-spectrum antibiotic treatment. There were no respiratory or gastroenteritis associated manifestations. CT Neck, Thorax, Abdomen and Pelvis on two separate occasions demonstrated a possible mild pancreatitis and an echocardiogram did not source any vegetations. Moreover, a concurrent PET-CT illustrated a complete metabolic response. There was only a single set of blood cultures which were positive, growing Staphylococcus Caprae from a peripherally inserted central catheter (PICC) line for