[Diagnostic error: incarcerated hernia].

Reported in this paper are 19 patients on whom incarcerated hernia had been pre-operatively diagnosed, which proved to be wrong during the operation. Various types of inflammation, including appendicitis in the hernial sac, as well as accumulation of pus in the hernial sac and abscesses, were the disorders which had led to false diagnosis in ten cases. Tumours were recorded from four patients and cysts in the round ligament of the uterus from another three, while a funicular hydrocele was detected in one patient. In one case, painful swelling through haematoma in the inguinal region had been caused by ruptured aortic aneurysm. Ultrasonographic diagnosis is recommended for all dubious cases. Surgery should be considered a preferable option in situations of lasting uncertain diagnosis, in order to avoid incarceration from remaining unnoticed.