Final answer:
In an ectopic pregnancy, a typical sign on an ultrasound scan is called a 'tubal ring'. This is a gestational sac seen in the fallopian tube. The 'tubal ring' sign can be misidentified as a corpus luteum cyst, hence careful interpretation of the ultrasound scan is necessary.
Step-by-step explanation:
In an ectopic pregnancy, an ultrasound scan (USS) often shows a typical sign called a 'tubal ring'. This is the sign of a gestational sac seen in the fallopian tube. The visual representation of a ectopic pregnancy on USS typically exhibits a cystic area, widely known as the 'tubal ring' sign. This image occurs when the ultrasound spotlights a thick-walled, circular gestational sac that contains clear fluid. However, it's important to note this sign can be misidentified as a corpus luteum cyst, hence a careful and expert interpretation of the ultrasound scan is necessary to make a conclusive diagnosis of an ectopic pregnancy.
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