Cerebellar involvement in Langerhans' cell histiocytosis: A progressive neuropsychiatric disease

We describe a 21-year-old patient who was being followed since the age of 3 1/2 years for Langerhans' cell histiocytosis. Although previously a blight and gifted student, the patient presented at age 16 1/2 with new-onset cer ebellar neurologic signs, obsessive-compulsive disorder, and dementia, Find ings on magnetic resonance imaging study of the brain were normal, but brai n single photon emission computed tomography with technetium. 99m. ethylene cysteinate dimer showed markedly decreased cerebellar perfusion. This case is unique for the wide extent of the central nervous system involvement in Langerhans' cell histiocytosis, which has not been reported previously. Al though obsessive-compulsive disorder has also been associated with several other cerebellar disorders, it is still unknown whether the cerebellum play s a role in its development. We suggest that in some cases, brain single ph oton emission computed tomography may be superior to magnetic resonance ima ging for demonstrating cerebellar disorder in Langerhans' cell histiocytosi s.