This report describes the case of a young man with a large calcification in the right thalamus that was first diagnosed at 9 years of age. Case history reveals specific eating rituals and other obsessive-compulsive personality traits during the patient's childhood and adolescence, fulfilling diagnostic criteria of obsessive-compulsive personality disorder. After a critical life event the patient develops anorexia nervosa. We suggest that our case and further literature provide evidence for an involvement of specific thalamic structures, such as the dorsomedial nucleus, in the development of anorexia nervosa. Furthermore, the treatment of the patient by a combined psychotherapeutic and pharmacotherapeutic approach is described. We focus on the beneficial effect of the atypical antipsychotic olanzapine, which can induce weight gain by an increase of leptin levels.