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OrthoVellum

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Oncology
intermediate
X-Type

Simple Bone Cyst (Unicameral Bone Cyst)

Benign Bone Lesions

An 11-year-old boy presents after feeling a "crack" in his upper arm while throwing a ball. He has mild arm pain but can move his shoulder. Radiograph shows a central, well-defined lytic lesion in the proximal humeral metaphysis with a thin sclerotic rim, mild cortical thinning, and a minimally displaced transverse fracture. A small bone fragment appears to have settled to the dependent portion of the cyst. Regarding simple bone cyst:

Mark each as TRUE or FALSE

A

Simple bone cyst (unicameral bone cyst/UBC) is a benign fluid-filled lesion; it occurs primarily in ...

B

The "fallen fragment sign" (bone fragment settling to the dependent portion of a fluid-filled cavity...

C

UBCs are malignant and metastasize; they are solid tumors not fluid-filled; the fallen fragment sign...

D

Treatment depends on location, activity status, and presence of fracture; pathologic fractures often...

E

"Active" cysts (adjacent to physis) have higher recurrence rates (50%) than "latent" cysts (separate...

Answer the questions to see explanations

Click T (True) or F (False) for each option