Meat balls: a pathognomonic ultrasound and computed tomography finding in mature cystic teratoma

"Floating ball sign" in the diagnostic imaging of mature ovarian teratomas in children

The "floating ball sign" (FBS) is a rarely described visual phenomenon found in mature ovarian teratoma imaging. It is characterized by the presence of movable, spherical areas within the cystic component of a tumor. Such visualization is possible both in cross-sectional imaging and ultrasonography. To evaluate the incidence of FBS in the pediatric population with regard to patients' age and tumor size. This is a retrospective study of pediatric patients operated on in a tertiary pediatric surgical center between January 2009 and December 2022 due to mature ovarian teratoma; the medical records were reviewed for the age at diagnosis, recurrences, tumor size, and their characteristics in preoperative imaging. Eighty-three patients (mean age 14, range 0-17) out of 91 met the inclusion criteria for the analysis. Eighty-seven operations on 90 ovaries were performed. Preoperatively 38 patients underwent CT, 13 MRI, and 39 received only the ultrasound examination. The FBS was identified in preoperative imaging diagnostics in 3 (3.3%) girls (14, 16 and 17 years of age). The average largest tumor dimension and volume were 142 mm and 1268 cc in the FBS group, and 73 mm and 252 cc in the remaining group, respectively. FBS tumors usually reach large sizes. Although the sign is rare in children, there are no scientific reports of its occurrence in the first life decade. Color flow mapping and cross-sectional imaging play a pertinent role in distinguishing this uncommon pattern from a malignant mass and enable the selection of an appropriate surgical approach.

Utility of the "floating ball sign" in diagnosis of ovarian cystic teratoma

Objective:

To evaluate the incidence of the “floating ball” sign in cross-sectional imaging modalities in patients with ovarian teratoma, and to investigate the relationship between the morphologic features of the teratoma and this sign.

Materials and Methods:

Preoperative computed tomography and magnetic resonance imaging studies of 112 women with a pathologic diagnosis of ovarian mature cystic teratoma (MCT) were reviewed for the presence of the floating ball sign. Tumor size, tumor characteristics and the number, size, and characteristics of floating globules were evaluated.

Results:

In 112 patients (mean age 35.5±16 years, range 5-84 years), 118 ovarian MCTs were diagnosed pathologically. The floating ball sign was demonstrated in cross-sectional imaging in 30 (25.4%) patients. Among 2 of them, MCT was associated with malignancy (squamous cell carcinoma). There was a significant relationship between the floating ball sign, tumor size, and the wall thickness of the tumor (p=0.003 and p=0.018, respectively). In linear regression analysis, a similarly significant relationship was found between the presence of this sign and tumor size and patient age (p=0.003 and p=0.035, respectively).

Conclusion:

The floating ball sign, as a pathognomonic sign for the diagnosis of ovarian teratomas, seems to be more common than is known. Although this sign is almost always seen in MCTs, it may rarely be seen in teratomas with malignant transformation. The relationship of this sign with the characteristics of the tumor can provide an insight into the occurrence of these balls.

Mature cystic teratoma of the ovary: a cutting edge overview on imaging features

Mature cystic teratoma (MCT) is the most common neoplasm of the ovary and includes at least two well- differentiated germ cell layers. Different combinations of mature tissue derivatives with varying arrangements in the tumour cause a wide spectrum of radiological presentation ranging from a purely cystic mass to a complex cystic mass with a considerable solid component. In different imaging modalities, each radiological feature reflects a specific pathologic equivalent that forms because of diverse compositions of histological components. Understanding uncommon findings as well as the classic signs with basic knowledge of pathological equivalents permits a more accurate diagnosis and guides adequate treatment. In this review, radiological features of MCT in different imaging modalities (US, CT, MR imaging) including specific signs and useful radiological artefacts with brief emphasis on pathological basics are discussed.

Teaching points

• Ovarian mature cystic teratomas (MCTs) have a wide spectrum of radiological presentation.

• Each radiological feature of MCT reflects a specific pathologic equivalent.

• Understanding radiological signs with basic knowledge of pathology can permit a more accurate diagnosis.

Ultrasound and differential diagnosis of fetal abdominal cysts

The present study aimed to investigate the use of ultrasound and differential diagnosis to diagnose a fetal abdominal cyst. A retrospective analysis of 41 cases of fetal abdominal cyst, which included ovarian cysts, choledochal cysts, intestinal duplication and mesenteric cysts, was performed. Imaging characteristics of various types of cysts were summarized, compared and discussed. Among 41 fetal abdominal cyst cases, there were 21 cases of ovarian cysts, 11 cases of bile duct cyst, six cases of intestinal duplication and three cases of mesenteric cyst. Each type of fetal cyst had its own distinctive characteristics on abdominal ultrasound examination. Ovarian cysts were located at one side of the bladder, round-shaped and observed in female fetuses; choledochal cysts were located in the hilar, were oblong- or oval-shaped and connected to the bile duct; intestinal duplication was located in the middle of abdomen, close to the intestine, and presented as an intestinal wall-like structure; mesenteric cysts were round-shaped with thin tensionless wall, presented with multiple chambers, and were easily deformable on compression. The findings of the present study demonstrated that a comprehensive analysis of the association between the cyst and its adjacent location, shape, wall thickness, motility and other aspects of dynamic changes via ultrasonography may provide a differential diagnosis of different types of fetal abdominal cysts.