A case of volvulus of ectopic spleen mistaken for twisted ovarian cyst is described. Attention is drawn to six points: 1) the rarity of the condition; 2) the persistent uncertainty concerning its aetiopathogenesis, even though over a century has passed since the first case was reported; 3) the mechanism leading to twisting of the spleen stalk; 4) the absence of specific symptoms and the consequent impossibility of preoperative diagnosis in most cases; 5) the ready confusion with ovarian cyst; 6) the reasons for supposing that the reported case was the result of congenital factors.