Dysplastic cerebellar gangliocytoma

Exam points

Striated/tigroid appearance of the cerebellar hemisphere leaves is essentially pathognomonic.
Buzz-phrase
"Unilaterally enlarged cerebellar hemisphere with thickened folia showing non-enhancing T2 hyperintense, ‘tiger-striped’ striations (WHO grade I dysplastic gangliocytoma)."

Because it is strongly associated with Cowden syndrome, further management includes imaging or clinical assessment for associated tumours, particularly:

• Breast
• Endometrial
• Thyroid

Trivia

• Also known as Lhermitte–Duclos disease.
• Part of PTEN-related diseases: adult Lhermitte–Duclos disease is a major diagnostic criterion for PTEN hamartoma tumour syndrome (Cowden syndrome) in current guidelines.
  • Adult LDD → think PTEN testing + lifelong screening for breast, thyroid, endometrial (± renal/colorectal) tumours.
• Many associated malformations are identified, consistent with PTEN/PI3K-AKT-mTOR overgrowth spectrum.
• When Lhermitte-Duclos disease is a manifestation of Cowden syndrome, it is termed COLD syndrome (Cowden-Lhermitte-Duclos syndrome)
• In contrast to adult-onset disease, paediatric cases typically do not show PTEN mutations.