Thick Skull

KEY FACTS

Terminology

• Skull thickening (ST)

  • Diploic space expanded ± thickened cortex

Imaging

• Widened calvaria (skull width)

  • Can be diffuse or focal

• NECT best for most causes of ST

  • Thin-section bone CT for detailed skull base evaluation

• MR C+ contrast: Look for adjacent dural involvement

Top Differential Diagnoses

• Normal variation (most common cause)

• Shunted hydrocephalus or infantile brain injury

  • Neonatal meningitis or cerebritis

  • Hypoxia/ischemia/hypoglycemia in neonatal period

  • Metabolic/genetic disease with infantile brain atrophy

  • ± phenytoin

• Metastases (diffuse sclerotic)

• Microcephaly

• Chronic anemias

Clinical Issues

• Often asymptomatic

• Patients with skull base ST

  • Look for foraminal/canal overgrowth/encroachment

  • May cause cranial neuropathy

• In many cases, evaluation of underlying brain can help to establish diagnosis

• Many tests can help discriminate among etiologies

• Skull findings often harbinger of underlying disease

• Therapy aimed at treating underlying etiology

Diagnostic Checklist

• What could be underlying clinical cause of ST?

  • Normal variant (most common)

  • Other: Metastases, anemia, parathyroid disorder, etc.

TERMINOLOGY

IMAGING