Cyst of Morgagni
Also known as hydatid of Morgagni. Embryological remnant of the Müllerian duct. Usually found as an appendage to the testis/epididymis, hence the alternative name of appendix testis. Present in about 90% of males, with about two-thirds showing bilaterality.
It can also be present in females, where they tend to appear around the fimbriae of the Fallopian tubes.
Can rarely twist.
It can be difficult to distinguish between a torsion of a pedunculated cyst of Morgagni and a testicular torsion clinically. The former is of little long-term importance whereas the latter should be dealt with very quickly and is important.