Abstract
BACKGROUND: Intramedullary spinal cord melanocytic neoplasm (IMSCMN) with hemorrhagic features is rare, and it is even rarer in children. The authors present a pediatric case of an IMSCMN involving the thoracic segment of the spinal cord. OBSERVATIONS: An 11-year-old previously healthy girl experienced intermittent low back pain for 5 months, followed by left foot drop, limb weakness, and abnormal gait. MRI revealed an intramedullary hemorrhagic spinal cord lesion at T9-11, with a long syrinx and cord edema. An MRI study of the brain and the remaining spinal cord was unremarkable. The patient underwent laminectomy and near-total resection of the tumor. Histopathological analysis confirmed the diagnosis of an atypical melanocytic neoplasm. Dermatological; ear, nose, and throat; and ophthalmological assessments, as well as a positron emission tomography study, were conducted to identify other neoplasms, which yielded unremarkable findings. LESSONS: This case highlights the diagnostic challenges of IMSCMN in children because of its rarity and nonspecific imaging features. IMSCMN should be considered in pediatric hemorrhagic spinal cord lesions with MRI findings of T1 hyperintensity, T2 hypointensity, and an associated syrinx. https://thejns.org/doi/10.3171/CASE25279.