Concurrent intracranial hemorrhage and spontaneous tumor Lysis syndrome as the initial presentation of KMT2A::AFF1-rearranged adult ALL: a case report.

BACKGROUND: KMT2A::AFF1-rearranged ALL is a high-risk subtype with an aggressive course. However, the simultaneous occurrence of catastrophic intracranial hemorrhage (ICH) and spontaneous tumor lysis syndrome (TLS) as the initial presentation is rare in adult patients and remains poorly characterized in the literature.

CASE PRESENTATION: A previously healthy 19-year-old Chinese male was admitted with sudden-onset drowsiness and impaired consciousness. Initial computed tomography revealed multiple intracranial hemorrhages with cerebral swelling. Laboratory findings were notable for extreme hyperleukocytosis (554.66 × 109/L) with 85% blasts (some with cup-like morphology), severe thrombocytopenia, and biochemical evidence of TLS. Despite emergency neurosurgical intervention and intensive supportive care, his clinical course was marked by the rapid progression of TLS and acute kidney injury, culminating in fatal cardiac arrest within 24 hours of admission. Postmortem flow cytometry and genetic analysis confirmed the diagnosis of pro-B ALL positive for the KMT2A::AFF1 fusion gene.

CONCLUSION: This case illustrates an exceptionally aggressive manifestation of adult KMT2A-rearranged ALL, characterized by the concurrent development of ICH and spontaneous TLS prior to the initiation of any leukemia-specific therapy. It underscores the critical importance of promptly recognizing this hyperacute syndrome in young patients presenting with unexplained neurological symptoms and profound hematologic abnormalities. Early multidisciplinary management and awareness of high-risk genetic profiles are essential, although the prognosis in such scenarios remains exceedingly poor.