Abstract
It is known for many years that heritability plays a role in the development of endometriosis in many patients. Deep endometriosis of the bladder is a rare presentation of the disease and bladder endometriosis was not reported in monozygotic twin studies so far. Since monozygotic twins share the same genes, concordance and differences in presentation of endometriosis may help to discriminate between genetic and environmental determinants. The remarkable resemblance in the presentation of bladder endometriosis in this monozygotic twin seems to indicate that genetic factors are of importance in the arising of deep endometriosis in the bladder too.