Is there a role for conventional MRI and MR diffusion-weighted imaging for distinction of skull base chordoma and chondrosarcoma?
BACKGROUND
Chordoma and chondrosarcoma are locally invasive skull base tumors with similar clinical symptoms and anatomic imaging features as reported in the literature.


OBJECTIVE
To determine differentiation of chordoma and chondrosarcoma of the skull base with conventional magnetic resonance imaging (cMRI) and diffusion-weighted MR imaging (DWI) in comparison to histopathological diagnosis.


METHODS
This retrospective study comprised 96 (chordoma, n = 64; chondrosarcoma, n = 32) patients with skull base tumors referred to the Paul Scherrer Institute (PSI) for proton therapy. cMRI signal intensities of all tumors were investigated. In addition, median apparent diffusion coefficient (ADC) values were measured in a subgroup of 19 patients (chordoma, n = 11; chondrosarcoma, n = 8).


RESULTS
The majority 81.2% (26/32) of chondrosarcomas displayed an off-midline growth pattern, 18.8% (6/32) showed clival invasion, 18.8% (6/32) were located more centrally. Only 4.7% (3/64) of chordomas revealed a lateral clival origin. Using cMRI no significant differences in MR signal intensities were observed in contrast to significantly different ADC values (subgroup of 19/96 patients examined by DWI), with the highest mean value of 2017.2 × 10(-6 )mm(2)/s (SD, 139.9( )mm(2)/s) for chondrosarcoma and significantly lower value of 1263.5 × 10(-6 )mm(2)/s (SD, 100.2 × 10(-6 )mm(2)/s) for chordoma (P = 0.001/median test).


CONCLUSIONS
An off-midline growth pattern can differentiate chondrosarcoma from chordoma on cMRI in a majority of patients. Additional DWI is a promising tool for the differentiation of these skull base tumors.
Department of Radiology, Kantonsspital Baden AG, Switzerland uta.muellerpfister@ksb.ch.
Uta
U
Müller
Department of Radiology, Kantonsspital Baden AG, Switzerland.
Rahel A
RA
Kubik-Huch
Center for Proton Therapy, Paul Scherrer Institute, Villigen, Switzerland.
Carmen
C
Ares
Princton Radiation Oncology Center, Monroe Township, NJ, USA.
Eugen B
EB
Hug
Department of Radiology, Kantonsspital Baden AG, Switzerland.
Roland
R
Löw
Institute of Neuroradiology, University Hospital Zürich, Switzerland.
Antonios
A
Valavanis
Department of Radiology, Kantonsspital Baden AG, Switzerland.
Frank J
FJ
Ahlhelm
D002813:Chondrosarcoma / Q000473:pathology*; D002817:Chordoma / Q000473:pathology*; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D019291:Skull Base / Q000473:pathology; D019292:Skull Base Neoplasms / Q000473:pathology*
ADC map; Magnetic resonance imaging (MRI); chondrosarcoma; chordoma; diffusion-weighted MRI (DWI); skull base tumor