Introduction: Lhermitte-Duclos disease (LDD), also known as dysplastic cerebellar gangliocytoma, is an uncommon disorder in children, characterized by being a slow-growing lesion of the posterior fossa, which mainly affects the granular cell layer of the cerebellar parenchyma and may be associated with other multiple hereditary hamartomas and neoplasms. Case Presentation: We report 2 cases of LDD in pediatric patients and describe clinical symptoms and radiological and histopathological characteristics. In addition, we analyzed the relation to Cowden Syndrome based on the International Cowden Syndrome Consortium Operational Criteria and the most updated guidelines by the National Comprehensive Cancer Network (NCCN Guidelines Version 1.2020). Conclusion: LDD is a very rare disease in childhood but should be considered in the differential diagnosis of posterior fossa lesions. LDD can mimic low-grade glial tumors or infectious diseases. Patients develop late clinical manifestations due to the slow-growing pattern, and conservative treatment with outpatient follow-up may be an option in asymptomatic children.