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. 2021 Mar 31;15(3):1–8. doi: 10.3941/jrcr.v15i3.4208

Table 2.

Differential diagnosis table for bony skull base lesions in a pediatric patient.

Differential Diagnosis Radiograph CT MRI
Poorly differentiated chordoma Poorly visualized. May be lytic, destructive bone-based lesion.

  • Variable. Usually lytic and destructive bone-based lesion, with surrounding soft tissue component.

  • Enhancement pattern: Soft tissue component may or may not enhance.

  • T1: iso-hypointense

  • T2: iso-hypointense (to muscle)

  • Enhancement pattern: variable. No significant enhancement was appreciated in our case.
Classical chordoma Poorly visualized. Expansile, lobulated lytic bone-based lesion.

  • Bone based lytic mass usually at the skull base or sacrum. Expansile soft tissue mass. Heterogeneous in their attenuation due to interspersing of tumor tissue (isoattenuating) and myxoid cyst or necrotic degeneration (hypoattenuating). Hyperattenuation may correspond to bony sequestration from destruction of bone rather than tumoral calcification.

  • Enhancement pattern: variable.

  • T1: iso-hypointense.

  • T2: usually hyperintense with a lobulated appearance characterized by multiple hypointense septae.

  • Enhancement pattern: Heterogeneous enhancement with a honeycomb appearance of septa.
Benign notochordal cell tumors Usually not seen. May present as a sclerotic medullary based lesion.

  • May be occult on imaging.

  • Mild to marked sclerosis, usually a vertebral body.

  • Enhancement pattern: no enhancement.

  • Low T1 and high T2 signal.

  • Enhancement pattern: no enhancement.
Ecchordosis physaliphora Poorly visualized.

  • Not well seen. May be a well circumscribed lytic or exophytic lesion at the dorsal clivus.

  • Enhancement pattern: no enhancement.

  • A bony stalk projecting from the clivus to the retroclival region is characteristic. Low T1 and high T2 signal.

  • Enhancement pattern: no enhancement
Chondrosarcoma Mixed sclerotic and lytic. Chondroid “rings and arcs” matrix. May have aggressive features. Expansile with periosteal reaction and soft tissue component.

  • Aggressive, lytic and expansile mass with endosteal scalloping, and soft tissue component. internal “rings and arcs” mineralization.

  • Enhancement pattern: heterogenous enhancement.

  • heterogenous low T1 and regions of iso-to-high T2 signal.

  • Enhancement pattern: heterogenous to marked.
Metastasis Poorly characterized. Variable in appearance, lytic to sclerotic.

  • Variable. May be lytic or sclerotic.

  • Enhancement characteristics: Variable

  • T1: usually hypo to iso-intense.

  • T2: Usually T2 hyperintense relative to normal bone

  • Enhancement pattern: variable