Comparison of thyroid volumes in patients with and without endometrioma

Background/Aim: Endometriosis is a condition characterized by endometrial tissue outside the uterus; it can lead to pelvic pain, although most cases remain asymptomatic. Abnormalities in the immune system have been hypothesized to contribute to development of ectopic endometrial tissues. Endometriosis is a chronic local inflammatory disorder associated with autoimmunity and thyroid disorders. This study aims to compare thyroid gland volumes between patients diagnosed with pathological endometrioma and those undergoing the removal of ovarian cysts for other gynecological reasons. Additionally, the study seeks to identify the coexistence of thyroid disease and determine the threshold value for thyroid volume in cases of endometriosis. Methods: This prospective cohort study included 64 patients who met the defined inclusion criteria. Thyroid volumes were measured in women aged 18–45 with ovarian cysts before surgery. Group 1 comprised individuals with surgically planned endometrioma diagnoses later histologically confirmed after surgery. The control group (Group 2) consisted of women with similar anthropometric characteristics undergoing gynecological surgery for non-endometrioma ovarian cysts. Thyroid volume, functional thyroid hormone levels, tumor markers, and demographic data were compared between the groups. Results: The endometrioma group exhibited a significantly higher thyroid volume. The thyroid volume variable demonstrated a diagnostic performance of 0.863 (0.771–0.956) regarding ROC-AUC in the presence of endometrioma, with a determined cutoff of 7.40. Although patients with endometrioma displayed a notably larger thyroid volume, cases of goiter were not observed. While there was no significant difference in thyroid hormones (serum TSH, T3 levels) between the groups, serum T4 was elevated in the endometrioma group, albeit within the normal laboratory range. All thyroid levels were within the normal range (euthyroid). As anticipated, serum CA-125 and CA19-9 levels were notably higher in the endometrioma group. Pathological reports did not indicate the presence of malignant cysts. Conclusions: Patients with endometriosis experience increased thyroid volume, even without clinical signs of thyroid disease. The potential clinical interplay between thyroid diseases, thyroid volume, and endometriosis warrants consideration during patient follow-ups.