A Transient "Blueberry Muffin" Rash in a Neonate with Acute Myeloid Leukemia: A Case Report and Review of the Literature.

A "blueberry muffin rash," typically attributed to congenital toxoplasmosis, rubella, cytomegalovirus, and herpes simplex virus (TORCH) infections, is a rare and underreported cutaneous manifestation of serious underlying pathology, including hematologic malignancies. We report a case of congenital acute myeloid leukemia (AML) in a full-term newborn who presented at day-of-life 0 with multiple blue to purple macules, patches, and indurated papulonodules and plaques on the trunk and extremities consistent with a "blueberry muffin rash". Notably, the rash was transient and spontaneously resolved within 24 hours of life, making it easy to overlook, potentially delaying life-saving treatment. This case reinforces the need for a full diagnostic workup and high clinical suspicion for leukemia in neonates presenting with a "blueberry muffin rash."