Unicameral bone cyst

Case contributed by Dr Matt Skalski


Shoulder pain and swelling.

Patient Data

Age: 3 years
Gender: Male

There is a solitary, unilocular, well-defined lucent lesion centrally located within the proximal humeral metaphysis which extends into the proximal diaphysis, occupying the entire diameter of the bone. The lesion is mildly expansile with mild cortical thinning. No periosteal reaction is evident. There are multiple lucent fracture lines extending through the lesion, with two small comminuted cortical fragments within the lesion , representing the "fallen fragment sign." There is minimal offset and no angulation of the distal humerus. 

Case Discussion

This lesion demonstrates typical radiographic characteristics of a simple/unicameral bone cyst with a pathological fracture demonstrating the diagnostic fallen fragment sign.   

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Case information

rID: 29278
Published: 14th May 2014
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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