Ultrasound feature discordance in a bilateral juvenile ovarian granulosa cell tumor: A case report


 BackgroundAs a rare ovarian stromal tumor, the juvenile ovarian granulosa cell tumor (JGCT) is mainly seen in premenstrual and young women. It associates with high malignancy and recurrence rate, and early diagnosis and treatment could improve prognosis. Most cases are unilateral solid-cystic or solid masses, while unilocular cystic masses are rarely seen. As cystic ovarian tumors are often misdiagnosed as benign cystic lesions or functional cysts, cystic JGCT should not be overlooked.Case presentationWe report this special case of a 10-year-old female patient. It’s the first reported JGCT with completely inconsistent bilateral imaging manifestations, including an extremely rare unilocular cystic JGCT. A large solid-cystic JGCT appeared in her left ovary, and left adnexal resection was performed. A unilocular cyst occurred in the right ovary two years later. It was with a regular shape and smooth inner wall, mimicking a benign cyst. Since the patient was young and had the desire to preserve the right ovary, follow-up was initially recommended. However, the cyst size increased rapidly and exploratory laparotomy was finally performed. Pathology showed a unilocular cystic JGCT.ConclusionsAs cystic masses in young patients are easily misdiagnosed as benign or physiologic lesions, this case emphasizes the importance of postoperative follow-up for JGCTs. Exploratory laparotomy of persistent cystic lesions should be considered when necessary.


Abstract
Background As a rare ovarian stromal tumor, the juvenile ovarian granulosa cell tumor (JGCT) is mainly seen in premenstrual and young women. It associates with high malignancy and recurrence rate, and early diagnosis and treatment could improve prognosis. Most cases are unilateral solid-cystic or solid masses, while unilocular cystic masses are rarely seen. As cystic ovarian tumors are often misdiagnosed as benign cystic lesions or functional cysts, cystic JGCT should not be overlooked.

Case presentation
We report this special case of a 10-year-old female patient. It's the rst reported JGCT with completely inconsistent bilateral imaging manifestations, including an extremely rare unilocular cystic JGCT. A large solid-cystic JGCT appeared in her left ovary, and left adnexal resection was performed. A unilocular cyst occurred in the right ovary two years later. It was with a regular shape and smooth inner wall, mimicking a benign cyst. Since the patient was young and had the desire to preserve the right ovary, follow-up was initially recommended. However, the cyst size increased rapidly and exploratory laparotomy was nally performed. Pathology showed a unilocular cystic JGCT.

Conclusions
As cystic masses in young patients are easily misdiagnosed as benign or physiologic lesions, this case emphasizes the importance of postoperative follow-up for JGCTs. Exploratory laparotomy of persistent cystic lesions should be considered when necessary.

Background
Juvenile ovarian granulosa cell tumors (JGCTs) are rare ovarian stromal tumors, accounting for approximately 0.1%-0.3% of all ovarian tumors 1,2 . Approximately 90% of patients are younger than 30 years old at the time of diagnosis, and 50% are less than 10 years old 3,4,5 . Compared with adult ovarian granulosa cell tumor, JGCT associates with high malignancy and recurrence rate, and early diagnosis and treatment could improve prognosis.
Most JGCTs are cystic-solid masses, while cystic especially unilocular cystic JGCTs are rarely reported.
To our knowledge, only 2 unilocular cystic JGCTs have been reported 3,6 . Besides, most JGCTs are unilateral, and only 4 cases of bilateral JGCTs have been reported 3,7 . JGCTs with completely inconsistent bilateral imaging manifestations have not been reported.
As cystic ovarian tumors are often misdiagnosed as benign cystic lesions or functional cysts, cystic JGCT should not be overlooked.

Case Presentation
A 10-year-old female patient was referred to our hospital and complained of persistent abdominal pain for 2 weeks. She experienced menarche 1 year ago, and her second but last period was 7 months ago.
Exploratory laparotomy showed a left ovarian mass. Thus, left adnexal resection was performed. Pathology showed a left ovarian juvenile granulosa cell tumor (JGCT). The right ovary was normal and reserved. A left ovarian JGCT (stage IC) was diagnosed, and postoperative chemotherapy was performed.
Regular follow-up showed no abnormalities. Two years later, Transabdominal ultrasound showed a 4.8×3.5×3.5 cm anechoic mass in the right ovary with a regular shape and smooth inner wall. The serum estrogen and progestin levels were normal. A physiological cyst was considered, and follow-up was continued. In the next 6 months, this cystic mass gradually increased in size to become a giant unilocular cystic mass measuring 21.3×18.1×9.9 cm, with a regular shape and smooth inner wall. Few blood signals were observed. Multiple small follicles ranging from 0.5 to 1 cm in diameter could be seen around the mass (Fig. 3). Serum estradiol was elevated to 171 pg/ml↑ (27-122 pg/ml), while other factors' levels were in the normal range. Right adnexal resection was performed, and pathology showed a unilocular cystic JGCT (Fig. 4). She received postoperative chemotherapy, and no recurrence was found in the following 15 months.

Discussion And Conclusion
JGCTs are mainly divided into three types based on their sonographic appearance: cystic-solid, solid and cystic masses 6. 8-10 .
Most JGCTs are cystic-solid masses with diameters greater than 5 cm in diameters. The characteristic sonographic appearance is predominantly hypoechoic solid mass, with multiple small anechoic areas scattered inside, indicating a "Swiss cheese sign". Cystic-solid JGCTs have relatively regular shapes and clear boundaries, with relatively rich blood ow signals in the solid part.
Most solid JGCTs were smaller than 5 cm in diameter. They are likely to be inhomogeneous hypoechoic, with regular shape and clear margins. Color Doppler ow imaging shows minimal or moderate blood signals.
Cystic JGCTs are rare, and most are multilocular cystic masses with thick cyst walls and septa. Some cystic portions may contain diffuse, homogeneous, low-level internal echoes. Color Doppler ow imaging shows minimal blood signals on the wall and septa. Unilocular cystic JGCTs are rarely seen, and only 2 cases have been reported 3,6 .
Cystic JGCTs should be differentiated from functional ovarian cysts, teratomas, endometriotic cysts and other benign ovarian cystic lesions. It's di cult to distinguish them by imaging features alone, but increased serum factors such as anti-Mullerian hormone (AMH) and estrogen levels might be helpful for predicting ovarian granulosa cell tumors 11,12 . Surgery is the most important treatment for JGCTs 13,14 .
In this case, the patient had a giant left ovarian cystic-solid JGCT at the rst onset and a giant right ovarian unilocular cystic JGCT two years later. As ovarian JGCTs have extremely low morbidity, the characteristics of this case were as follows: 1) bilateral JGCTs; 2) completely inconsistent bilateral ultrasonic imaging features; and 3) a unilocular cystic JGCT on one side. All these characteristics described above are extremely rare. This is the rst case of bilateral JGCTs with signi cantly inconsistent imaging ndings as well as a unilocular cystic mass, which is rare and can be easily mistaken as a benign cystic lesion.
Cystic ovarian tumors are often misdiagnosed as benign cystic lesions or functional cysts. As JGCTs are more commonly seen in young women, they are more likely to be misdiagnosed. This case suggests the importance of postoperative follow-up for JGCTs. Exploratory laparotomy is still necessary when cystic lesions gradually increase in size and do not disappear after months of follow-up. Abbreviations JGCT, juvenile ovarian granulosa cell tumor Declarations Ethics approval and consent to participate Our study design and protocol were approved by the ethics committee of Peking union medical college hospital, and written informed consent of the patient to participate was obtained.

Consent for publication
Consent Written, informed consent for publication was obtained from the patient for publication of this case report. Publication was approved by all authors and tacitly or explicitly by the responsible authorities where the work was carried out.
Availability of data and materials Not applicable.   Transabdominal image of the right ovarian mass. A. Long-axis view; B. Short-axis view. A mass 21.3×18.1×9.9 cm in size was observed in the pelvic cavity, with a regular shape and smooth inner walls. Multiple small follicles (arrow) ranging from 0.5 to 1 cm in diameter could be seen around the mass.