Background and objective

Many men tend to desire a larger penis than women want because it symbolizes masculinity and sexual prowess. Micropenis is a normally developed penis with at least 2.5 standard deviations below the mean size in stretched length for age. Unlike micropenis, small penis syndrome (SPS) refers to uncomfortable feelings about one’s penis size, even though penis size does not fall within the micropenis category. Some men seriously worry or feel ashamed of their penis size, and they may meet the diagnosis criteria of body dysmorphic disorder (BDD). Unlike micropenis, the differential diagnosis of BDD is very important, because it is associated with high rates of committing suicide. In particular, when combined with BDD, it is known that poor outcomes after cosmetic interventions are expected. Several validated assessment tools are available to differentiate SPS and the degree of BDD, but they are still controversial. Furthermore, many physicians are performing cosmetic interventions on patients who have not been fully assessed and counseled by a psychologist, thereby leading to unsatisfactory results. Therefore, we aimed to clarify the definition of disease for penis size and review its diagnosis and treatment. This will be helpful both for physicians to enable them to provide adequate counseling and treatment and for patients to help them avoid unsatisfactory treatment.