Chondrosarcoma is a malignant bone tumor that produces cartilage matrix and is classified as the third most common primary malignant bone tumor. It predominantly occurs in middle-aged to older adults (40-70 years). The pelvis, proximal femur, proximal humerus, and ribs are the most commonly affected sites. Radiologically, it is characterized by chondroid matrix (arcs and rings calcification), endosteal scalloping, and markedly high signal on T2-weighted MRI sequences (hyaline cartilage). Low-grade (Grade I-II) tumors grow slowly and are resistant to chemotherapy/radiotherapy; surgery is the only curative treatment.
Age Range
40-70
Peak Age
55
Gender
Male predominant
Prevalence
Uncommon
Chondrosarcoma develops from mesenchymal stem cells in the bone marrow or through malignant transformation of pre-existing benign cartilage lesions (enchondroma, osteochondroma); tumor cells produce hyaline cartilage matrix and the calcification of this matrix manifests on imaging as characteristic arcs and rings mineralization pattern — this pattern represents the lobular growth of the tumor and calcification of the peripheral cartilage matrix of each lobule. The tumor starts from the medullary cavity and erodes the inner cortical surface (endosteal scalloping); this finding is one of the most important distinguishing features from benign enchondroma and reflects internal cortical thinning. On T2-weighted MRI sequences, cartilage matrix produces very high signal because hyaline cartilage contains 70-80% water and this high free water content leads to long T2 relaxation time. In higher-grade tumors (Grade III), cartilaginous differentiation decreases, cellularity increases, and enhancement becomes more prominent; this dedifferentiation process is radiologically reflected as decreased matrix mineralization and aggressive periosteal reaction.
Lobular mass with arcs and rings chondroid matrix calcification on CT combined with markedly high T2 signal on MRI, accompanied by endosteal scalloping — in a middle-to-older age patient, this combination is the most characteristic radiological appearance of chondrosarcoma.
Calcification of chondroid matrix produces characteristic arcs and rings mineralization pattern reflecting the lobular structure of the tumor. This calcification pattern is specific to cartilage-producing tumors and is the most important diagnostic finding of chondrosarcoma. CT demonstrates matrix mineralization much more sensitively than conventional radiography. Mineralization amount is inversely proportional to tumor grade — dense in low-grade tumors, minimal or absent in high-grade tumors.
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Arcs and rings pattern calcification specific to chondroid matrix is seen within the lesion, consistent with a cartilage-producing tumor.
Endosteal scalloping resulting from tumor growing from the medullary cavity and eroding the inner cortical surface. Scalloping depth exceeding 2/3 of cortical thickness and length exceeding 2/3 is significant for malignancy. This finding is one of the most important criteria in distinguishing enchondroma (benign) from chondrosarcoma (malignant). The full extent of scalloping is evaluated on CT multiplanar reformats.
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Endosteal scalloping exceeding 2/3 of cortical thickness is seen on the inner cortical surface adjacent to the lesion, favoring chondrosarcoma.
Chondroid matrix shows markedly high signal on T2-weighted sequences — this signal results from hyaline cartilage containing 70-80% water. The lobular structure of the tumor is clearly seen on T2 as bright lobules with intervening low-signal septa. Calcified areas show low signal on all sequences. T2 signal intensity is directly proportional to chondroid matrix content.
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Lobular mass with markedly high T2 signal and intervening low-signal septa, consistent with chondroid matrix-producing tumor.
The tumor shows low-to-intermediate signal intensity on T1-weighted sequences. T1 signal is low due to high water content of chondroid matrix. Calcified areas show low signal. Lobular architecture can be seen on T1 but is not as prominent as on T2. T1 sequence is important for evaluating intramedullary extent of the tumor.
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Lobular mass with low-to-intermediate signal intensity on T1-weighted sequences; intramedullary extent should be evaluated.
Lobular septa and peripheral areas of chondrosarcoma show ring-and-arc pattern enhancement on contrast-enhanced MRI. Cartilage matrix in lobule centers does not enhance — this feature is a contrast enhancement pattern specific to chondroid tumors. Enhancement may be more heterogeneous and diffuse in higher-grade tumors. Enhancement degree shows positive correlation with tumor grade.
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Ring-and-arc pattern enhancement in lobular septa on post-contrast sequences, consistent with chondroid matrix-producing tumor.
Low-grade chondrosarcomas (Grade I) show minimal or no diffusion restriction — due to low cellularity and high water content chondroid matrix. In higher-grade tumors (Grade II-III), diffusion restriction becomes prominent as cellularity increases. ADC values are inversely proportional to tumor grade. DWI is helpful in tumor grading and detection of dedifferentiated chondrosarcoma component.
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Diffusion restriction in cellular components of the tumor should be evaluated on DWI; prominent restriction should be considered in favor of high grade or dedifferentiation.
Cortical destruction and soft tissue extension are seen in high-grade chondrosarcomas (Grade II-III). Contrast-enhanced CT is important for evaluating the vascularity of soft tissue component and its relationship with adjacent structures. In low-grade tumors, cortex may remain intact or only endosteal scalloping is seen.
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Cortical destruction and soft tissue extension on contrast-enhanced CT, consistent with high-grade chondrosarcoma.
Criteria
Most common subtype (85-90%). Arises from the medullary cavity. Grade I-III grading. Pelvis, proximal femur, proximal humerus predilection.
Distinct Features
Typical arcs and rings calcification, endosteal scalloping, high T2 signal. As grade increases, mineralization decreases while enhancement and cellularity increase.
Criteria
High-grade non-cartilaginous sarcoma component within low-grade chondrosarcoma. Bimorphic appearance — two distinct components. Very aggressive, poor prognosis.
Distinct Features
Two distinct components on CT and MRI: chondroid matrix mineralization (low-grade) on one side and aggressive destructive soft tissue mass (high-grade) on the other. Dedifferentiated component shows marked diffusion restriction on DWI. Bimorphic pattern is pathognomonic.
Criteria
Chondrosarcoma originating from bone surface (periosteum). Rare. Located on outer cortical surface, medullary invasion in late stages.
Distinct Features
Mass with chondroid matrix mineralization on the bone surface. Saucerization (saucer-shaped erosion) of cortex. No medullary invasion initially. T2 high signal on MRI confirms chondroid nature.
Criteria
Malignant transformation from pre-existing benign cartilage lesion (enchondroma or osteochondroma). Increased risk in Ollier disease and Maffucci syndrome. Suspected when cartilage cap >2 cm (in osteochondroma) or symptomatic enchondroma.
Distinct Features
Growth, pain, development of endosteal scalloping in previously known benign lesion. Cartilage cap thickening in osteochondroma (measured on MRI T2). New aggressive findings in enchondroma (cortical destruction, soft tissue mass). Change on follow-up imaging is a critical diagnostic clue.
Distinguishing Feature
Enchondroma is benign, does not show endosteal scalloping (or <2/3), size usually <5 cm, enhancement minimal or absent, no pain or growth. Chondrosarcoma shows endosteal scalloping >2/3, size >5 cm, ring-and-arc enhancement, and clinical symptoms (pain).
Distinguishing Feature
Osteosarcoma produces osteoid matrix (cloud-like mineralization) and typically occurs in young patients. Chondrosarcoma produces chondroid matrix (arcs and rings calcification) and is common in middle-to-older adults. Distinction with chondroblastic osteosarcoma may be difficult.
Distinguishing Feature
Bone metastases usually present as multiple lesions in patients with known primary tumor history and do not show chondroid matrix calcification. Chondrosarcoma is usually a solitary lesion containing chondroid matrix.
Distinguishing Feature
Giant cell tumor is epiphyseal, has no matrix mineralization, shows low-to-intermediate T2 signal. Chondrosarcoma is metaphyseal/diaphyseal, shows chondroid matrix calcification, and has markedly high T2 signal.
Urgency
moderateManagement
Geniş cerrahi rezeksiyon tek küratif tedavidir. Konvansiyonel kondrosarkom kemoterapi ve radyoterapiye dirençlidir. Dediferansiye kondrosarkomda kemoterapi uygulanabilir. İntralezyonel küretaj düşük dereceli tümörlerde (Grade I) tartışmalı olarak uygulanabilir ancak nüks riski yüksektir.Biopsy
NeededFollow-up
Cerrahi sonrası ilk 2 yıl 6 ayda bir MR + akciğer BT (yüksek derece) veya yıllık (düşük derece). 5 yıl sonra 2 yılda bir takip. Lokal nüks MR ile, akciğer metastazı BT ile izlenir.Chondrosarcoma is a malignant bone tumor requiring accurate grading for surgical planning. Distinction from enchondroma is critically important — radiological-pathological correlation is mandatory to avoid unnecessary surgery or inadequate treatment. 5-year survival is >90% in low-grade tumors while 10-20% in dedifferentiated chondrosarcoma. Pelvic location is associated with worse prognosis as it challenges surgical margin adequacy.
Chondrosarcoma requires surgical resection; it is resistant to chemotherapy and radiotherapy. Prognosis is good for low-grade tumors (90%+ survival) but poor for high-grade and dedifferentiated types. Differentiation from enchondroma is critically important.