Thick Skull, Localized

Miral D. Jhaveri, MD

DIFFERENTIAL DIAGNOSIS

Common

Less Common

Rare but Important

ESSENTIAL INFORMATION

Key Differential Diagnosis Issues

Helpful Clues for Common Diagnoses

Hyperostosis Frontalis Interna
- Middle-aged, older women
- Bilateral, symmetrical (bifrontal)
- Overgrowth mostly inner table
- Ends at coronal suture
Meningioma
- Three patterns
  - Sclerotic: Dural-based mass, adjacent calvarium thickened, ± dural tail
  - Intradiploic: Intradiploic mass thickens, expands calvaria ± cortical destruction/thickening
  - “En plaque”: Nodular dural thickening + associated extensive hyperostosis (juxta-orbital most common site)
Metastasis (Osteoblastic)
- Common with prostate, breast metastasis
- Look for associated focal/diffuse dura-arachnoid involvement

Helpful Clues for Less Common Diagnoses

Fibrous Dysplasia
- Young patient
- Medullary expansion (“ground-glass”)
Paget Disease
- Late osteosclerotic phase
- Focal areas of sclerosis in expanded diploic space (“cotton wool” appearance)
Dyke-Davidoff-Masson
- Cerebral atrophy + ipsilateral compensatory osseous hypertrophy & hyperpneumatization of paranasal sinuses
Cephalhematoma (Calcified)
- Birth trauma, subperiosteal hemorrhage
- Early: Thin calcified shell, late sequelae: Incorporation of the calcified rim into the outer table of the skull
Chronic Subdural Hematoma (Calcified)
- Chronic calcified SDH along inner table simulates thick skull
- Looks like “double” skull on MR