Navigating Cytomegalovirus Retinitis in a Patient With Myelodysplastic Syndromes Transitioning to Acute Myeloid Leukemia Post Transplant: A Case Study.

We present a case of cytomegalovirus (CMV) retinitis with UL97 resistance in a patient undergoing treatment for acute myeloid leukemia (AML), highlighting the complex interplay between hematological malignancies and CMV management. A 49-year-old female patient with myelodysplastic syndromes (MDS) with 4.5% blasts and TP53 mutations ((variant allele frequency (VAF)) 5.2%) underwent an allogeneic stem cell transplant complicated by acute graft versus host disease (GvHD) and subsequent CMV viremia. Her UL97 resistance posed significant challenges to CMV management, necessitating a transition from ganciclovir to foscarnet and maribavir. The CMV polymerase chain reaction (PCR) levels initially >10,000 copies/mL decreased to <300 copies/mL with combination therapies, though fluctuations persisted until letermovir prophylaxis was initiated. Six months after the transplant, AML relapse was treated with cladribine, cytarabine, granulocyte-colony-stimulating factor/filgrastim, and mitoxantrone (CLAG-M) and venetoclax, leading to measurable clearance of TP53 mutations to undetectable levels by NGS and reduction of CD34+ blasts from 25% to 0%. However, the patient developed vision loss and was diagnosed with CMV retinitis, requiring intravitreal and systemic foscarnet alongside laser prophylaxis for retinal detachment. The complexity of her case was compounded by foscarnet-induced acute kidney injury (AKI), requiring intravenous hydration and suspected GvHD, managed with steroids and supportive care. This case illustrates the aggressive nature of MDS-AML progression, the critical role of vigilant CMV surveillance, and the nuanced approach needed for treatment, balancing efficacy against potential side effects. The successful navigation of these complexities offers valuable insights for similar cases.