Classification and histological diagnosis
The diagnosis of endometriosis requires visual assessment of the pelvis by laparotomy or laparoscopy. Deep and infiltrating endometriosis can be diagnosed by feel, using a blunt probe to assess whether a nodule is superficial or deep. As laparoscopic skills and techniques have developed, so more subtle appearances of endometriosis, such as nonpigmented implants, have been recognised9. In one study, the incidence of endometriosis rose due to increased recognition of ‘subtle’ implants from 15% of laparoscopies between January and May 1986 to 65% in the period
Laparoscopy is associated with significant morbidity, and it has a number of inherent faults. The diagnostic accuracy of laparoscopy relies upon the operator’s visual
experience, the presence of coexisting pelvic adhesions and preoperative bias can all influence the interpretation of the laparoscopic findings11. In addition, microscopic disease 12,13
can theoretically be missed at laparoscopy. Microscopic disease has been found in the visually normal peritoneum of 13% of women with and 6% without endometriosis14 (this difference is not significant). However, Redwine15 failed to demonstrate any endometriosis in biopsies from normal peritoneum taken from 33 women, of whom 24 had endometriosis elsewhere and nine had a normal pelvis at laparoscopy. He argued that the discrepancy between his and previous findings could only be explained by ‘the discriminatory threshold of the clinicians’ in defining what is visually normal peritoneum.