Immature teratomas remain difficult to diagnose: A cross-sectional study

The ultrasound features of ovarian mature teratomas are well defined. However, literature regarding the ultrasound features of immature teratomas is lacking and features can often be confused with those of mature teratomas. The objective of this study was to evaluate the subjective assessment of ultrasound examiners of anonymised static B mode ultrasound images of immature and mature teratomas.

An electronic questionnaire was distributed to levels 1 to 3 ultrasound examiners containing 23 anonymised ultrasound images including nine different immature teratomas and nine different mature teratomas. The images were collected retrospectively, and the reference test was the final histology of the surgically removed masses. The sensitivity and specificity test of the subjective assessment for each histological group was calculated. The live (at the time the scan was performed) subjective impression of each tumour was also recorded and the level of the examiner that performed the scan was noted.

There were a total of 43 responses (30 from level 1, 9 from level 2 and 4 from level 3 examiners. The sensitivity and specificity of subjective assessment ranged from 16.3% to 97.7% and 81.6% to 96.1%, respectively, for all histological groups. The sensitivity and specificity to correctly diagnose mature teratomas and immature teratomas were 41.3% (95% CI: 36.3%-46.4%), 82.2% (95% CI: 78.9%-85.1%) and 41.2 % (95% CI: 36.2%-46.3%), 81.6 % (95% CI: 78.3%-84.7%), respectively. There was no statistical difference in the diagnostic performance of the subjective assessment of examiners between mature and immature teratomas (p = 0.975).

Diagnostic performance of static 2D ultrasound images for mature and immature teratomas is low. Immature teratoma still pose a diagnostic challenge.