Koro syndrome is a culturally related disorder characterized by intense anxiety that the penis (vulva or nipples in females) is shrinking or retracting and will recede into the body. Usually it occurs in epidemics in Southeastern Asia, being extremely rare in western countries. The condition is more common in males and is classified within Obsessive Compulsive and Related Disorders.

A 27-year-old single man was referred to the psychiatric department. By the age of 23, he began worrying that his penis was shrinking and retracting into the abdomen. He described these thoughts as intrusive, ridiculous and repetitive. During the first months the thoughts were not very disturbing but he progressively developed an urge to verify the length of his penis several times a day. To diminish the anxiety provoked by the obsessive doubts on penis length, he started to have repetitive thoughts and mental images about sexual acts, to consume pornography compulsively and to increase his masturbatory behaviors (from some times a week to several times a day). He described those thoughts and behaviors as unpleasant and uniquely driven to reduce anxiety provoked by obsessions.

He was prescribed fluvoxamine 200 mg/day and initiated cognitive behavioral therapy with good response. Y-BOCS score decreased from 30 at initial evaluation to 18 after 3 months of treatment.

Koro syndrome is a very rare condition in psychiatry in western countries, usually presenting secondarily to other psychiatric disorders. Awareness of this diagnosis and knowledge on its management are critical to provide optimal care to patients.

The authors have not supplied their declaration of competing interest.