Endometriosis (Fallopian tube)

The fallopian tube is a common site of endometriosis. These tubes were removed at the time of caesarian section. Note decidual reaction in the endometrial tissue.

These low and high magnification photos of a regional lymph node reveal the presence of endometrial tissue. This is difficult to explain by two theories (regurgitation-implantation and metaplasia) advanced as the mechanism of origin of endometriosis. A picture such as this must be kept in mind when staging pelvic cancer.