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Speech bubble sign

Case contributed by Dr Maulik S Patel


Presented with a painless lump in the posterior side of the left knee for the last few months.

Patient Data

Age: 75 years
Gender: Male

There is a well-defined, anechoic, avascular lesion (59 x 37 x 16 mm) on the posteromedial side of the left knee. The lesion shows a neck going in the deeper plane between the medial head of the gastrocnemius and the semimembranosus tendon. There are few tiny echoes in the lesion. There is no leak from the lesion. Overlying subcutaneous fat shows a normal echopattern.

Case Discussion

Ultrasound shows a popliteal cyst. Its neck between the medial head of gastrocnemius and semimembranosus tendons suggests the lesion being a Baker cyst. This appearance is known as a "speech bubble".

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Case information

rID: 75654
Published: 4th Apr 2020
Last edited: 4th Apr 2020
Inclusion in quiz mode: Included

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