To the Editor.—Endometriosis has been found to occur in almost every organ and location of the female body. This condition is well known to gynecologists, but the general surgeon is rarely faced with it in his or her practice, and, for this reason, the correct diagnosis is seldom made preoperatively. The establishment of a correct diagnosis preoperatively is important, not only for academic reasons, but mainly to avoid unnecessary anesthesia and operations in such patients.
Patients.—We had occasion to operate on three patients who proved to have unsuspected endometriosis and who exemplify the pitfalls in a preoperative diagnosis of this condition. The first patient was a 32-year-old woman who was undergoing an operation because of a myomatous uterus and who was found to have a hard, irregular, nut-sized mass that was palpable in the anterior wall of the rectum. Because of a suspicion of malignancy, an anterior resection