Ovarian hemangiomas are rare benign vascular malformations that originate in the female genital tract. In fact, there are fewer than 60 well-documented cases of ovarian hemangiomas in the literature [1]. These neoplasms occur in individuals of all ages, ranging from childhood through to the postmenopausal period [2]. The vascular proliferation is typically histologically classified as a cavernous, capillary, or mixed type, with cavernous being the most common [3]. Yet, occasionally, a variable amount of ovarian tissue stroma can be present, indicating inflammation, hemorrhage, hemosiderin deposits, or calcification. While ovarian hemangiomas are believed to represent non-functional stromal luteinization leading to vascular proliferation and bleeding in the abdominal cavity, the exact pathogenesis is currently unknown [4][5]. These hemangiomas are usually detected incidentally during surgery or autopsy, and they are generally small in size. In very rare cases, however, they may grow to larger sizes, be located bilaterally, and become symptomatic. The clinical manifestations of ovarian hemangiomas may include pain, which is the most common symptom, ascites, acute abdomen and abdominal masses, and signs of both hyperandrogenism and hyperestrogenism [6][7]. Additionally, findings such as elevated CA-125 levels may mimic the signs of ovarian neoplasms [8].

In this report, we present a rare case of unilateral ovarian hemangioma radiologically interpreted as pelvic schwannoma in a postmenopausal patient. Written informed consent was obtained from the patient.

Ovarian hemangioma was first described by Payne etal. in 1869 in a female patient aged 25 who had bilateral ovarian hemangioma and abdominopelvic hemangiomatosis. Such neoplasms are extremely rare adnexal masses. The cases reported in the literature span a patient age range of 4 months to 81 years, and ovarian hemangiomas are frequently identified as incidental findings following surgery [9]. Given that adnexal masses, particularly growing ones, are important due to their increased risk of malignancy during the postmenopausal period, close follow-up is essential and rare pathologies such as ovarian hemangiomas should also be kept in mind, especially if the mass is richly vascularized and increasing in size. In the case reported here, the ovarian mass growing in size over a two-year period, accompanied by suspicion of pelvic schwannoma, in a postmenopausal woman, led to a diagnosis of ovarian hemangioma.

While the etiology of ovarian hemangiomas remains unknown, these lesions are considered to be defective vascular formations caused by hormonal effects, particularly during pregnancy or in the course of infections [10]. Some cases have presentations such as ovarian torsion, acute abdominal pain, mass-effect-induced abdominal enlargement, ascites, and elevated CA-125 levels, clinically imitating an ovarian carcinoma [11][12]. In the present case, the patient had only intermittent lower abdominal pain and no other complaints. As she had experienced no pain for two years, she did not attend the control visit as requested and later presented with an enlarged and painful left ovarian mass. Although ovarian hemangiomas appear to be non-functional, some studies suggest a connection between ovarian hemangiomas and thrombocytopenia, postmenopausal bleeding, endometrial hyperplasia, or endometrial carcinoma [13][14]. Hence, differential diagnoses in terms of ovarian hemangioma include tubo-ovarian mass, chocolate cyst, degenerated uterine or intraligamentous myoma, angiosarcoma, lymphangioma, ovarian tumor (e.g., fibrothecoma, Brenner tumor, mature or immature teratoma), or ovarian malignancy [15]. Pelvic localization of schwannomas, which are benign retroperitoneal peripheral nerve sheath tumors originating from Schwann cells, should also be considered in relation to differential diagnosis [16]. In the reported case, there was a high suspicion of pelvic schwannoma due to the MRI findings, leading to surgical therapy being performed, which resulted in the mass being histopathologically diagnosed as ovarian hemangioma.

MRI imaging and color Doppler ultrasound are both valuable techniques for detecting preoperative ovarian hemangioma with rich vascularization [12][17]. MRI characterizes the mass, where T2-weighted images reveal the isointensity of cerebrospinal fluid, which significantly intensifies on contrast-enhanced T1-weighted images [18]. In the reported case, MRI demonstrated interval enlargement to 54 × 44 mm. The lesion appeared hypointense on the T1-weighted imaging and hyperintense on the T2-weighted and fat-suppressed sequences, with marked heterogeneous enhancement following contrast administration. Thus, radiologic differential diagnosis primarily indicated pelvic schwannoma.

Hemangioma should be considered as a differential diagnosis when a growing adnexal mass or a hemorrhagic ovarian lesion is encountered in a postmenopausal woman [4]. The preferred course of treatment is surgical excision of the suspected mass via either laparotomy or laparoscopy. Ovarian-sparing surgery is recommended for young women, especially in relation to non-suspicious tumors, whereas ovariectomy is preferred in postmenopausal women. Moreover, histopathological confirmation remains the gold standard for diagnosis and appropriate management [19]. The prognosis of ovarian hemangiomas is generally favorable, with timely diagnosis and appropriate surgical intervention typically leading to positive patient outcomes [20].

Growing adnexal masses in postmenopausal period are of importance due to the malignancy potential. MRI seems to be helpful in differential diagnosis and histopathological investigation is the gold standard in final diagnosis. Surgical excision of the suspected mass is essential in postmenopausal women, whereas ovarian sparing surgery should be considered in women who desire fertility.