Coexistence of Ovarian Mature Cystic Teratomas and Endometriosis: An Update.

Mature cystic teratomas (MCTs) and endometriosis are the most common benign diseases in women of reproductive age. Their coexistence was traditionally considered rare. However, recent evidence suggests otherwise. This study aims to investigate the coexistence of MCTs and endometriosis and to analyze the clinical characteristics of this complex condition. We retrospectively reviewed 285 women who underwent ovarian cystectomy for MCTs between January 2014 and December 2020. Serum anti-Müllerian hormone (AMH) levels were measured preoperatively and at 1 and 6 months postoperatively. Patients were followed for at least 6 months to assess recurrence. 57 (20%) patients had coexistence of MCTs and endometriosis (complex group); while 228 (80%) patients had MCTs alone (teratoma group). Endometrioma was found in 15 (26.79%) patients and peritoneal endometriosis in 41 (73.21%) patients. 39 (68.42%) patients had minimal/mild endometriosis, and 18 (31.58%) patients had severe endometriosis. Compared with the teratoma group, the complex group had a higher prevalence of dysmenorrhea (22.8% vs. 7.5%, p = 0.001) and higher serum CA125 levels (20.91 ± 16.93 vs. 14.00 ± 12.03 IU/mL, p = 0.01). Unclear cleavage planes between normal ovarian tissue and the cyst capsule were more frequent in the complex group (15.8% vs. 4.8%, p = 0.004). A greater decline in AMH at 1 month postoperatively was observed in the complex group (31.97% vs. 18.02%, p = 0.036), whereas no difference was noted at 6 months. Recurrence rates were similar between groups (p = 0.484). Coexisting MCTs and endometriosis are not uncommon and is associated with more severe dysmenorrhea, elevated serum CA125 levels, and poorly defined cleavage planes between normal ovarian tissue and the cyst capsule. This complex condition may warrant consideration beyond the conventional management of either disease alone.