Exact radiological-pathological correlation of chondrosarcomas using a patient-specific 3D mold.

Objective: To identify aggressive regions in high-grade and dedifferentiated chondrosarcomas on MRI by obtaining an exact correlation between radiology and histopathology.

Materials and methods: One chondrosarcoma grade II (CSII), chondrosarcoma grade III (CSIII) and dedifferentiated chondrosarcoma (DDCS) were segmented on (DCE-)MRI images. Around the segmentations, a patient specific mold was constructed and 3D-printed with cutting grooves perfectly aligned with selected MRI slices. In this way, resection specimens could be cut at the same locations as the MRI slices. Histopathology slides were stained with hematoxylin-eosin and CD31 (vascularization) and correlated with the (DCE-)MRI. Histopathologically, atypical cartilaginous tumor (ACT), CSII, CSIII and DDCS regions were delineated and vascular hotspots were selected by an experienced pathologist. Exact point-to-point correlation was performed.

Results: ACT, CSII, CSIII and DDCS regions all had similar mean signal intensity on T1-weighted images. On fat-saturated T2-weigthed images, CSII and CSIII regions had a higher mean signal intensity. On fat-saturated T1-weighted images after gadolinium contrast injection and on wash-in parametric maps DDCS regions had the highest mean signal intensity and highest wash-in values. There was a higher microvessel density in CSII and CSIII regions. This corresponded with a thick enhancing rim on fat-saturated T1-weighted images after gadolinium contrast injection and with a higher wash-in.

Conclusion: This new 3D mold helps to identify high-grade chondrosarcoma regions with myxoid. This may be useful for targeted biopsy and histopathological investigation.