Lhermitte-Duclos Disease and Neurofibromatosis Type 1 in a Patient With a Follow-Up of More Than Twenty Years

Lhermitte-Duclos disease (LDD) is a rare condition, with approximately 300 cases reported. We present over 20 years of the natural history of a young woman with the rare coexistence of LDD and neurofibromatosis type 1 (NF-1), as well as intractable epilepsy, infantile spasms, and cognitive and motor impairments. The cerebellar gangliocytoma remained stable on neuroimaging from early childhood into adulthood, while subclinical electroencephalogram (EEG) abnormalities improved during early adolescence but persisted into adulthood. This case highlights the importance of interdisciplinary care and close monitoring for evolving neuropsychiatric, developmental, and ophthalmological manifestations. The investigation and outcome identify novel combinations of electroencephalographic patterns, genetic abnormalities, and clinical phenotype in LDD and NF-1, offering valuable insights into the complex interplay of these rare conditions.