Table 14.

Differential diagnoses of simple (unicameral) bone cyst.

Diagnosis	Morphology	Common Genetic Alterations
Fibrous dysplasia	Irregular, curvilinear trabeculae of woven (or rarely lamellar) bone without osteoblast rimming; inconspicuous osteoblasts; sharpey fibers; and osteoclasts bland fibroblastic stroma	GNAS mutations (50–70%)
Intraosseous ganglion	Cavity without lining; filled with mucoid viscous material	None (probably degenerative)
Lipoma	Nodules of mature adipose tissue, often fibrotic	Unknown