Friday, April 27, 2012

Wormian Bones: Differential Diagnosis #6

Wormian bones are ossified structures that are found within the sutures. Their incidence varies widely among different ethnic groups, with a slightly greater prevalence among females. Some authors only consider them abnormal if they number 10 or more. The differential for Wormian bones is broad and includes many entities, which can be remember by the mnemonic PORKCHOPS:

DiseaseNotes
PPyknodysotosisassociated with osteosclerosis and acro-osteolysis
OOsteogenesis imperfecta
RRickets
KKinky hair syndromeaka Menkes disease
CCleidocranial dysostosismay have absent clavicles
HHypothyroidism / Hypophosphatasia
OOtopalatodigital Syndrome
PProgeria
Pachydermoperiostosis
Primary acro-osteolysis (Hadju-Cheney)

SSyndrome of Downs

Example of Wormian bones (Normal Skull in top left)
Source: Wikipedia

The most common location of Wormian bones is the lambdoidal suture.  The most common cause is actually idiopathic.

References