CASE REPORT Late-Onset Obsessive-Compulsive Disorder Associated with Left Cerebellar Lesion Matteo Tonna & Rebecca Ottoni & Paolo Ossola & Chiara De Panfilis & Carlo Marchesi Published online: 27 April 2014 # Springer Science+Business Media New York 2014 Abstract The onset of obsessive-compulsive disorder (OCD) after age 50 is rare and generally related to an organic etiology. An involvement of fronto-striatal circuits has been strongly suggested, whereas cerebellum remains so far scarcely ex- plored. We present here the description of a “pure” late- onset OCD associated with a cerebellar lesion, neither comor- bid with other mental disorders nor with neurological syn- dromes. To our knowledge, this condition was not previously described in literature. The patient is a 62-year-old woman who developed a late-onset OCD associated with a left cere- bellar lesion due to an arachnoid cyst in the left posterior fossa. We debate the possible role of the cerebellar lesion in favoring a transition from a predisposing liability (namely an obsessive-compulsive personality disorder and a depressive status) to the onset of OCD in this woman. Keywords Obsessive-compulsive disorder (OCD) . Obsessive-compulsive personality disorder (OCPD) . Depression . Cerebellum . Arachnoid cyst Introduction The onset of obsessive-compulsive disorder (OCD) presents a bimodal distribution, with a first peak in childhood and the second in early adulthood. The onset after age 50 is relatively rare and generally related to an underlying structural brain damage, such as infections, degenerative disorders, brain in- jury, or cerebrovascular lesions [1]. The study of such “organ- ic” late-onset OCDs may provide a deeper insight into the complex neurobiology of this disorder. Although the pathophysiology of OCD remains controver- sial, increasing evidence supports a role for several functional and structural brain abnormalities in OCD, particularly in- volving not only the fronto-striatal-thalamic circuits but also basal ganglia, corpus callosum, superior temporal gyrus and hippocampus, amygdala, and cerebellum [2]. With specific respect to cerebellum, congenital or acquired cerebellar disturbances may be associated with ruminative and obsessive behaviors [3], and a decrease in cerebellar gray matter, particularly in the left upper area, has been found in OCD patients [4]. Furthermore, cerebellum has been impli- cated in the pathogenesis of compulsions by virtue of its involvement in learning motor sequence and stereotyped ac- tivities [5]. In this case report, we present a late-onset OCD associated with left cerebellar lesion due to an arachnoid cyst in the left posterior fossa. Case Presentation B.B. was a 62-year-old Caucasian woman who sought treat- ment at the outpatient service at the Psychiatric Clinic of the University of Parma, Italy, for the recent onset of obsessive symptoms. The patient never got married and had no children. At the time of the psychiatric evaluation, she was working as a primary school teacher and was also actively engaged in voluntary associations. She described herself as an “anxious” person; she acknowledged to be orderly and scrupulous in her R. Ottoni : P. Ossola : C. De Panfilis : C. Marchesi Department of Neuroscience, Psychiatric Unit, University of Parma, Parma, Italy M. Tonna Mental Health Department, Local Health Service, Parma, Italy C. Marchesi (*) Dipartimento di Neuroscienze, Unità di Psichiatria, Ospedale-Padiglione Braga, Università di Parma, Via Gramsci 14, 43125 Parma, Italy e-mail: carlo.marchesi@unipr.it Cerebellum (2014) 13:531–535 DOI 10.1007/s12311-014-0561-8