Cartilaginous Tumors

Image Details. Xray’s and MRI s in 1^st figure shows the enchondroma (EC), atypical cartilaginous tumor (ACT) and High-grade chondrosarcoma (CS). Endosteal scalloping with cortical expansion (black arrow) is seen on ACT (2^nd) image. Aggressive periosteal reaction with extension into the soft tissue is seen high grade CS image(3^rd). 2^nd figure shows the findings that help to differentiate EC from CS.

 CS is a malignant cartilage-forming tumor and generally occurs within the medullary area of bones. Diagnosis of CS may be difficult without correlation of radiological and clinicopathological features. The radiographic features of CS s are often very characteristic, and a correct diagnosis can be made by radiological imaging’s. Grading of CS is important and is useful in predicting histological behavior. Prognosis of CS is closely related to histologic grading.

According to the newest edition of World Health Organization classification (2020, 5^th edition), cartilaginous tumors are classified as benign (such as osteochondroma and EC), intermediate (chondromatosis and ACTs), and malignant (such as grade I–III CS, dedifferentiated CS, and mesenchymal CS).  The terminology of ACT is reserved for low-grade (grade 1) CS located within the appendicular skeleton both in long and short tubular bones whereas the terminology of grade 1 CS is reserved for tumors of the axial skeleton (pelvis, scapula, and skull base flat bones) to reflect the poorer clinical outcome of these tumors at these sites. Differentiation of EC from ACT an CS Gr 1 may be challenging on radiological imaging’s. Findings that help to differentiate EC from ACT on X ray is presented in table of 2^nd image. Radiographies are essential for the diagnosis  and differentiation of chondrogenic tumors.

Radiographic Differentiation of EC and CS

                                                             Enchondroma(EC)           Chondrosarcoma(CS)

Cortical Destruction:                                    8% ,                                 90% 

Endosteal Scalloping:                                  10% ,                               90% (involves more than 2/3 cortical thickness)

Permeative&Moth eaten Destruction:           - -,                                   ++ (High Grade CS)

Periosteal Reaction:                                      --                                     ++

Size                                                               <5-6 cm                           >5-6 cm

Soft Tissue extension                                  ------------                           +++++++++

Follow_up                                                    Stable                                Unstable