Dysplastic cerebellar gangliocytoma (DCG) is an extremely rare tumor with nearly 300 reported cases since 1920. We intend to generate awareness about 1. Presentation-slow growth, posterior fossa location, pressure effects & spatial heterogeneity (non-concentrated and multifocal involvement) with recurrence potential, 2. Genetic testing and cancer surveillance for its relation to Cowden syndrome.

Primary nervous system tumors in the USA have an estimated age-adjusted incidence rate of 25 per 100,000 persons, 30 percent being malignant. DCG is classified under “neuronal and mixed neuronal-glial tumors” World Health Organization grade I, although it is still unclear whether it is a true neoplasm, hamartoma, or malformation. Can be sporadic (60%) or related to Cowden syndrome (multiple hamartoma autosomal-dominant phacomatosis caused by PTEN mutations). Recurrence is reported up to 10%. Intraoperative sonography for lesion delineation, preventive C1 laminectomy for post-operative progression and pharmacological research are in the anvil.

MRI brain showed diffusion restriction in the vermis and right cerebellar hemisphere. There was no significant enhancement but the regional cerebral blood flow (CBF) and cerebral blood volume (CBV) were increased. There was a striped appearance of this lesion in T2, suggesting DCG. Also moderate mass effect with some deformity of the posterolateral brainstem and compression of the 4th ventricle. Redo surgical options are being discussed with the patient at the moment. Genetic testing for PTEN mutation in him and family members is under consideration.

A case of Lhermitte-Duclos disease with post-operative recurrence, cerebellar dysfunction and unique imaging features, is presented. We hope this provides awareness for future patient management and research.