Authors: Matsubara Y, Fujioka T, Ikeda T, Kusanagi Y, Matsubara K, Ito M Supernumerary ovaries are extremely rare. Herein is reported a case of supernumerary ovary detected in a 31-year-old woman who complained of lower abdominal pain on her left side. Ultrasonography indicated a cystic mass in the pelvis, the size of which fluctuated periodically. [...]