A conceptual history of Koro.

Koro is a culture-bound syndrome characterized by a fear that the genitals or breasts will retract into the body and cause death. Here we consider the history of ideas about Koro, from early concepts in traditional Chinese medicine (TCM) to contemporary ideas from medicine and sociology. This conceptual history reveals important issues about the classification (nosology) of Koro. In doing so, it demonstrates the need to integrate standardized phenomenological criteria with etiological models in order to capture the important features of complex behavioral disorders in the cross-cultural setting.