Thecoma is a rare and almost invariably benign ovarian sex-cord stromal tumor that is predominantly diagnosed in postmenopausal women. In this patient group, an asymptomatic course is frequently observed. Hormone-secreting thecomas are, however, more frequent among younger women and associated with uterine bleeding, abdominal distension, and pain. Clinical findings and imaging studies are needed to make the diagnosis, but the exact tumor type is often determined postoperatively.
The ovarian tumor thecoma belongs to a group of sex-cord stromal tumors, and the name stems from its lipid-rich stromal cells that are strikingly similar to theca cells located in the ovarian follicles   . Thecoma is virtually always a benign tumor (although rare malignant cases have been reported), and it is principally diagnosed in postmenopausal women  . The clinical presentation depends on whether the tumor contains cells that produce steroid hormones (termed luteinized thecoma) or not (typical and rarely calcified thecoma)  . Luteinized thecoma has been shown to appear at a slightly younger age and may produce estrogenic, virilizing, or mixed effects   . Non-secreting tumors rarely cause symptoms. Certain authors report that more than 60% of post-menopausal women are asymptomatic . Tumors that synthesize estrogen, on the other hand, produce symptoms such as uterine bleeding (and menstrual irregularities in younger women), abdominal pain and/or distension, whereas an abdominal mass might be identified during a physical examination  . In addition, between 20-50% of cases suffer from concomitant endometrial carcinoma   . Although they can present with worrying symptoms, the clinical course of thecoma is benign and proper surgical treatment results in a cure .
The presence of abnormal uterine bleeding or menstrual abnormalities should prompt the physician to perform a meticulous clinical and imaging workup. Firstly, a detailed patient history including the onset of symptoms and their progression must be noted, followed by a complete physical examination, with an emphasis on abdominal and pelvic inspection/palpation. As soon as initial suspicion is raised, imaging studies should be employed. Abdominal ultrasonography (US) is a highly useful initial method in the evaluation of abdominal pathologies. The presence of a unilateral adnexal hypoechoic mass possessing clear borders and a weak vascular signal on Doppler imaging are hallmarks of a thecoma . To confirm the diagnosis, however, more advanced studies - computed tomography (CT) and magnetic resonance imaging (MRI), are often necessary. CT shows an isodense or hypodense tumor, whereas isointense signaling on T1- weighted images and either hypointense or isointense signaling T2- weighted images are typical findings (although some authors claim that even hyperintense signals can be encountered on T2, depending on the amount of surrounding edema)     . In addition to imaging procedures, the use of ovarian serum tumor marker (CA 125) in the diagnostic workup might also be recommended, as it is frequently elevated in the presence of a neoplastic process in the ovaries  .