Thursday, May 10, 2012

Bone Fluid-Fluid Level: Differential Diagnosis #10

A fluid-fluid level is a fairly specific sign for the entities listed below. Being aware of the differential is important since the underlying etiology could be either benign or very malignant. Other features and the clinical context can help narrow down the diagnosis further. The mnemonic here is not the greatest, but to remember the diagnoses, think of the DNA bases: ACGT:

AAneursymal Bone CystBenign; 80% < age 20
GGiant Cell TumorSeen only after physeal closure (age>20)
TTelangiectatic OsteosarcomaMost common location: Femoral metaphysis

The age of the patient is an important factor to consider, as the GCT only occurs after physeal closure.

ABC with fluid-fluid level, best seen on CT
Source: Radiology Assistant