The specimen is a tumour called a dermoid cyst which was found on an ovary. It can be seen to contain skin with sebaceous and sweat glands which are normal elements of skin, five well-formed teeth and a few long silky hairs. The mechanism by which germ cells with the capacity to grow into any of a number of tissues like this, become trapped in the cyst and develop into tissue and organs, is not understood. They are however associated with embryonic development and seem to be hormone -driven and connected to oestrogen levels, since women who suffer from polycystic ovary syndrome or endometriosis are more likely to develop dermoid cysts.
Dermoid cysts come in two types, a solid type and the more common cystic type like the one shown here. The cystic form tend to be roundish and smooth on the outside and hollow except for various mature tissues such as hair, skin, teeth, sweat glands, nails, cartilage, thyroid tissue and even eyes, which form in the space. The cysts begin to form during development in areas such as the face, the brain or lower back, and in the ovaries where they can continue to develop during a woman’s reproductive years. They are generally benign tumours but in 2% of cases there are malignant cells present. In the majority of cases they are asymptomatic and only cause problems by pressing on other organs and can cause problems with urination due to pressure on the bladder. Occasionally they can cause torsion of the ovary or become infected, which may cause abdomen/lower back pain and abnormal vaginal bleeding. This necessitates removal of the cyst or the whole ovary. Since their discovery, centuries ago, they’ve been subject of fascination and various supernatural causes have been invoked to explain them including witches, nightmares and adultery with the devil. In fact they are most likely to be early stage fertilised eggs that escape from the female reproductive tract and develop incompletely and abnormally around the ovary.