[Imperforate hymen. A simple, but overlooked diagnosis].

About one among 2000 girls have hymen imperforatus. Some are recognized because of mucocolpos at birth, but the diagnosis is usually not detected before puberty. Menstrual blood will accumulate behind the imperforate hymen, and result in abdominal pain, distension of the lower abdomen and often in acute urinary retention. The diagnosis and treatment is easy, but many patients have seen several doctors before the diagnosis is clear.