To the Editor: We appreciate the opportunity to respond and comment on this fascinating case, in which the presentation of obsessive-compulsive symptoms immediately followed the incidence and treatment of a pineal gland germinoma in an adolescent young man. In our case, the patient began to exhibit psychotic symptoms (e.g., olfactory and auditory hallucinations, belief in mind reading) and obsessive-compulsive symptoms (e.g., making idiosyncratic hand gestures, exhibiting a preoccupation with checking the time, and insisting that the bed covers be folded a certain way) during the development of a pineal tumor, but the precise etiology was obfuscated by a variety of factors, including a basal ganglia stroke. While the psychotic symptoms remitted after successful treatment of the tumor with chemotherapy, the obsessive-compulsive symptoms persisted. This is consistent with the case report of "Jonathan," reported by Mr. De Nadai and colleagues, for whom the onset of obsessive-compulsive symptoms began abruptly after the successful treatment of a pineal germinoma. In contrast to our case, however, Jonathan had no known basal ganglia involvement. These findings further implicate pineal body dysfunction in the pathophysiology of obsessive-compulsive disorder (OCD).