Ovarian serous borderline tumour in a young woman – MRI findings

A 21-year-old G0P0 woman with no medical history was referred to our institution for a sonographically detected cystic right adnexal mass. She has a history of pelvic discomfort without other complaints. Physical examination was normal. Laboratory findings were also normal except for an elevated CA 125 65.2 U/mL (normal <35.0).

MRI examination revealed a cystic tumour arising from the right ovary with 7.5 cm. On T2-weighted images, the signal intensity of the cyst content was high and two small nodular peripheral solid components were detected, adhering to its internal wall, with low signal (Fig. 1a, b). The normal left ovary was present with follicles (Fig. 1a).

On pre-contrast T1-weighted images, the mass exhibited slightly high signal intensity (Fig. 1c). On contrast-enhanced fat-suppressed T1-weighted images, wall enhancement and solid component enhancement were detected (Fig. 1d). Finally, the ADC map (Fig. 1f) from diffusion-weighted image (Fig. 1e) demonstrates marked hypointensity of the solid component, in keeping with its dense cellularity. Surgical excision was proposed and accepted by the patient. The histopathological investigation revealed a typical ovarian serous borderline tumour.

Borderline ovarian tumours are uncommon ovarian neoplasms, intermediate between benign and malignant types, corresponding to 5% of all epithelial ovarian tumours. [1, 2]

Serous borderline tumour represents the most common type of borderline tumours arising in the ovary, and typically, it is confined to the adnexa and presents an indolent course. [3] However, up to 6.8% of these tumours can progress to low grade serous carcinoma. [3] Serous borderline tumours are divided into typical (90%) and borderline tumours with micro-papillary patterns (5%–10%). [4] These neoplasms usually present as bilateral adnexal masses with more proliferation of papillary projections than do benign cystadenomas, they are often seen in younger patients, and laboratory findings show the serum CA-125 level mildly elevated. [2, 3, 5, 6] The peak age of presentation is 45 years. [5]

Small tumours usually do not cause symptoms and are often detected as an incidental finding on sonography. [7] Larger or more advanced neoplasms might cause pain or pelvic discomfort.

The diagnosis of this type of tumour is based on histopathological examination. As they are staged using the same ovarian cancer staging of malignant ovarian neoplasms [5], MRI plays a crucial rule in this evaluation.

There are no pathognomonic imaging features of borderline ovarian tumours and they frequently resemble a benign lesion. Nevertheless, some pathologic and MR imaging studies suggested that large papillary projections are highly suggestive of borderline or malignant neoplasms. [1, 8]

The preferred treatment is bilateral oophorectomy. Fertility sparing procedures such as unilateral oophorectomy or cystectomy are related with a higher incidence of recurrence when compared with bilateral oophorectomy (10-20% vs. approximately 5% for radical surgery). [3, 4] Young age (<30 years) has also been found to be a risk factor for recurrent disease in patients treated conservatively. As in this case, patients should be instructed to complete child-bearing within a short time frame following initial diagnosis, due to the high risk of recurrence. [3]

The most important feature in predicting an adverse outcome in serous borderline tumours is the presence of serous lesions involving the peritoneum (so-called invasive implants). [3, 4] Tumours without invasive implants, as in this case, have been considered to be nonaggressive tumours, associated with a good prognosis and high survival rate.

Follow-up using ultrasound imaging is mandatory, with particular attention paid to the remaining ovary in conservatively treated young patients. [4]

Written informed patient consent for publication has been obtained.