Partial Oculomotor Nerve Palsy Revealing PDCD10-Related Familial Cerebral Cavernous Malformation in a Child

Familial cerebral cavernous malformation (FCCM) is a hereditary vascular disorder associated with pathogenic variants of KRIT1 (CCM1), CCM2, and PDCD10 (CCM3). Among these, PDCD10-related FCCM is considered the most severe subtype and is characterized by early onset, multiple lesions, frequent brainstem involvement, and an increased risk of intracranial hemorrhage. Brainstem symptoms may be the initial manifestations. However, isolated oculomotor nerve palsy in childhood is rare. We report the case of a 17-month-old girl with normal developmental milestones who developed mild right ptosis, strabismus, and impaired adduction and upward gaze of the right eye at nine months of age. There was no family history of seizures or intracranial hemorrhage. Computed tomography of the head revealed multiple intracranial calcifications. Susceptibility-weighted angiography (SWAN) magnetic resonance imaging (MRI) revealed multiple cerebral cavernous malformations (CCMs), and follow-up MRI one year later demonstrated new lesions, including pontine involvement. Fast imaging employing steady-state acquisition (FIESTA) revealed hemorrhagic changes adjacent to the right oculomotor nerve within the interpeduncular cistern, suggesting that the partial oculomotor nerve palsy was associated with focal hemorrhagic involvement. Genetic analysis revealed the presence of a novel PDCD10 variant. This case highlights that PDCD10-related FCCM may initially present with isolated cranial neuropathy during childhood and subsequently show rapid radiological progression. Careful longitudinal follow-up is required because of the risk of future neurological deterioration.