Calvarial Hemangioma

KEY FACTS

Terminology

• Benign intraosseous skull lesion with predominantly vascular and some avascular components

Imaging

• Best clue

  • Sharply marginated expansile skull lesion

• Frontal, temporal, parietal bone in decreasing order

• Most often solitary, but multiple in 15%

• Best imaging tool: Bone CT

  • Sharply marginated expansile lesion

  • Thin peripheral sclerotic rim in 1/3

  • Intact inner and outer table

  • Outer table often more expanded than inner table

  • Trabecular thickening with radiating spicules

• MR signal characteristics dependent on

  • Quantity of slow-moving venous blood

  • Ratio of red marrow to converted fatty marrow

  • Hypointense trabeculae

• T1WI

  • Hypo- to isointense

• T2WI

  • Usually heterogeneously hyperintense (“light bulb bright”)

• T1 C+

  • Enhances diffusely and heterogeneously

  • “Fills in” with delayed imaging

  • May have dural tail

Pathology

• Classified on basis of dominant vessels: Capillary, cavernous, or mixed

Clinical Issues

• Most often asymptomatic

• Calvarial hemangiomas rare: 0.2% of bone tumors

• Rarely requires treatment

TERMINOLOGY

IMAGING