Lhermitte-Duclos disease (dysplastic cerebellar gangliocytoma): a malformation, hamartoma or neoplasm?

Dysplastic gangliocytoma (Lhermitte-Duclos disease) is a rare disorder, characterized by a slowly progressive unilateral tumour mass of the cerebellar cortex. The fundamental nature of this apparently benign entity and in particular its pathogenesis remain unknown. The debate, whether it represents a neoplastic, malformative or hamartomatous lesion, is still in progress. Lhermitte-Duclos disease was recently encountered to be part of a multiple hamartoma-neoplasia complex (Cowden's syndrome).

The present account gives a review of the pertinent literature with emphasize on clinical presentation, radiological findings, surgical procedures, histopathological features and pathogenetic considerations of dysplastic cerebellar gangliocytoma.

Dysplastic cerebellar gangliocytoma clusters within the third to fourth decades of life. Cranial nerve palsies, unsteadiness of gait, ataxia and sudden neurological deterioration as a result of occlusive hydrocephalus are frequent signs and symptoms. Associations with other congenital malformations, such as megalencephaly, polydactylia, multiple haemangioma and skull abnormalities are common. Magnetic resonance imaging (MRI) is the diagnostic modality of choice and reveals characteristic non-enhancing gyriform patterns with enlargement of cerebellar folia. Surgery is the therapeutic procedure generally performed and complete resection was attempted in the majority of cases. The histopathological findings of Lhermitte-Duclos disease include widening of the molecular layer, which is occupied by abnormal ganglion cells, absence of the Purkinje cell layer and hypertrophy of the granule cell layer.

Dysplastic gangliocytoma of the cerebellum is of benign behaviour and its incidence is extremely rare. The disease should be considered when confronted with a young adult presenting with clinical signs of progressive mass effect in the posterior fossa. The lesion is hypointense on T1- and hyperintense on T2-weighted magnetic resonance images. Recognition of the disease is of particular importance, as the frequent but under-reported coexistence with Cowden syndrome, should prompt thorough clinical and apparative investigation to detect or exclude concomitant malignancies.