Presentation
Painful left arm after a fall.
Patient Data
Age: 13
Gender: Male
From the case:
Unicameral bone cyst with fallen fragment sign
{"current_user":null,"step_through_annotations":true,"access":{"can_edit":false,"can_download":true,"can_toggle_annotations":true,"can_feature":false,"can_examine_pipeline_reports":false,"can_pin":false},"extraPropsURL":"/studies/48314/annotated_viewer_json?lang=us"}
There is a solitary lucent lesion in the proximal left humerus with an associated fracture and an osseous linear fragment in the dependent portion on the lateral aspect consistent with a fallen fragment sign of a unicameral bone cyst.
Case Discussion
The commonest location for a unicameral bone cyst is in the proximal humerus in 60% of the cases. The most frequent complication of the cyst is a pathological fracture as shown by the above case and is the commonest reason for presentation.