Endometriosis is easily missed in adolescents. (Typically Early-Stage Disease).

BIG SKY, MONT. -- Endometriosis in adolescents has a very different appearance than in adults, Dr. Joseph S. Sanfilippo said at an ob.gyn. update sponsored by the Geisinger Health System.

"If you don't look carefully you'll miss endometriosis in adolescents," cautioned Dr. Sanfilippo, professor of ob.gyn. at the University of Pittsburgh.

Endometriosis in teens is typically early-stage disease.

Unlike the classic blue, brown, or black lesions that gynecologic surgeons are accustomed to seeing in adults, biopsy-proven endometriosis in adolescents often takes the form of clear vesicles or small red polypoid hemorrhagic or petechial lesions.

"When I have a teenager, I always get a peritoneal biopsy to confirm the diagnosis," he said. "It's simple to do through the laparoscope."

When a parent asks about the prognosis for her 17-year-old daughter with endometriosis, the honest answer is "bad." Symptomatic adolescent-onset endometriosis is most often a lifelong problem that will progress to severe fibrotic disease.

The exception involves adolescents who are found to have an outflow tract obstruction, as has been reported in various series to be the case in 10%-40% of teens with endometriosis.