The diagnosis of peritoneal endometriosis at the time of laparoscopy is often made by the observation of typically puckered black or bluish lesions. There are also numerous subtle appearances of peritoneal endometriosis. The lesions are frequently non-pigmented. Red flame-like lesions, glandular excrescences, and subovarian adhesions must be considered as the most active lesions. Sometimes, however, subtle endometriotic lesions can be the only lesions seen at laparoscopy.
Donnez, J., Squifflet, J.-P., Casanas-Roux, F., Pirard, C., Jadoul, P., & Van Langendonckt, A. (2003). Typical and subtle atypical presentations of endometriosis. Obstetrics and Gynecology Clinics of North America, 30(1), 83-93. https://doi.org/10.1016/S0889-8545(02)00054-2 (Original work published 2003)