Radiological features of 24 periosteal chondrosarcomas

Classification of Chondrosarcoma: From Characteristic to Challenging Imaging Findings

Chondrosarcomas can be classified into various forms according to the presence or absence of a precursor lesion, location, and histological subtype. The new 2020 World Health Organization (WHO) Classification of Tumors of Soft Tissue and Bone classifies chondrogenic bone tumors as benign, intermediate (locally aggressive), or malignant, and separates atypical cartilaginous tumors (ACTs) and chondrosarcoma grade 1 (CS1) as intermediate and malignant tumors. respectively. Furthermore, the classification categorizes chondrosarcomas (including ACT) into eight subtypes: central conventional (grade 1 vs. 2–3), secondary peripheral (grade 1 vs. 2–3), periosteal, dedifferentiated, mesenchymal, and clear cell chondrosarcoma. Most chondrosarcomas are the low-grade, primary central conventional type. The rarer subtypes include clear cell, mesenchymal, and dedifferentiated chondrosarcomas. Comprehensive analysis of the characteristic imaging findings can help differentiate various forms of chondrosarcomas. However, distinguishing low-grade chondrosarcomas from enchondromas or high-grade chondrosarcomas is radiologically and histopathologically challenging, even for experienced radiologists and pathologists.

Peripheral and periosteal chondrosarcoma: MRI-pathological correlation in 58 cases

OBJECTIVE

To determine whether MRI can distinguish atypical cartilaginous tumour/grade 1 peripheral/periosteal chondrosarcoma (ACT/Gd1 PP-CS) from high-grade peripheral/periosteal chondrosarcoma (HG-PP-CS) or dedifferentiated peripheral/periosteal chondrosarcoma (DD-PP-CS).

MATERIALS AND METHODS

Retrospective review of patients diagnosed between January 2007 and December 2020 who had undergone resection of PP-CS. Data collected included age, sex, and skeletal location. Histological tumour grades based on surgical resection were classified as ACT/grade 1 PP-CS, HG-PP-CS, or DD-PP-CS. A variety of MRI features were reviewed independently by 2 musculoskeletal radiologists blinded to final diagnosis and compared between the 3 groups. For statistical analysis, HG-PP-CS and DD-PP-CS were combined.

RESULTS

Fifty-eight patients fulfilled the inclusion criteria, 31 (53%) males and 27 (47%) females with a mean age at diagnosis of 46.1 years (range 11-83 years), 14 (24%) of whom had an underlying diagnosis of diaphyseal aclasis. Forty-one (70.7%) cases were peripheral and 17 (29.3%) periosteal, 38 (66%) involving the flat bones, 15 (26%) the major long bones, 3 (5%) the spine, and 2 (3%) the bones of the hands and feet. Final histology revealed 33 (57%) ACT/Gd1-PP-CS, 18 (31%) HG-PP-CS, and 7 (12%) DD-PP-CS. Periosteal tumours were 16 times more likely to be HG/DD-CS compared to peripheral tumours (p < 0.001). Intra-medullary tumour extension was predictive of HG/DD-CS (p = 0.004) for both tumour types, while cap thickness (p = 0.04) and a diffuse cap type (p = 0.03) were differentiating features of low-grade and high-grade peripheral CS.

DISCUSSION

A variety of features can help differentiate low-grade from high-grade peripheral/periosteal CS, the most significant being origin from the bone surface.

Clinical, Radiological, and Histopathological Characteristics of Periosteal Chondrosarcoma with a Focus on the Frequency of Medullary Invasion

Periosteal chondrosarcoma is an extremely rare malignant cartilage-forming tumour that originates from the periosteum and occurs on the surface of bone. Often, it is difficult to distinguish periosteal chondrosarcoma from other tumours, and reports in the literature are scarce. This study aims to investigate the characteristics of periosteal chondrosarcoma, focusing particularly on medullary invasion. Among 33 periosteal cartilaginous tumours, seven patients with pathologically proven periosteal chondrosarcoma were identified retrospectively. The average tumour size was 5.4 cm in the long axis; two tumours were smaller than 3.0 cm. Six tumours were resected with a wide margin, and the remaining tumour had a marginal margin. Histology revealed that six tumours (85.7%) had invaded the medullary cavity; three of these did not show invasion into the medullary cavity on MRI evaluation. Neither local recurrence nor metastasis was observed among these patients. The frequency of invasion of the medullary cavity was higher than that reported previously. The recommended treatment for periosteal chondrosarcoma is resection with an adequate margin. Therefore, surgeons should consider the possibility of medullary invasion when attempting to achieve a histologically negative margin, even if the tumour does not show invasion into the medullary cavity on MRI.

Surface bone sarcomas: an update on current clinicopathological diagnosis and treatment

Surface bone sarcomas are rare malignant bone tumours. Osseous and cartilaginous surface bone sarcomas are the most common, with parosteal and periosteal osteosarcomas, periosteal chondrosarcomas and secondary peripheral chondrosarcomas being the most frequent.

Their clinical symptoms are non-specific and include pain for several months, swelling and limited range of motion of the adjacent joints.

Prompt diagnosis is important, as biological behaviour, imaging and histopathologic characteristics, treatment and prognosis differ considerably from their conventional intramedullary counterparts. Moreover, their imaging characteristics are not infrequently non-characteristic and may be misinterpreted as juxtacortical benign lesions leading to incorrect diagnosis and treatment, with life-threatening repercussions. Molecular studies and histopathological sampling are essential for accurate diagnosis.

There are still numerous issues regarding the biology, pathophysiology and treatment options of these entities due to their rarity.

Cite this article: EFORT Open Rev 2021;6:905-917. DOI: 10.1302/2058-5241.6.210064

Chondrosarcoma of the Ribs

Chondrosarcoma is a unique kind of tumor that originates from the cartilage-producing neoplastic mesenchymal cells and appears in both the appendicular and atlantoaxial skeleton. It is the second most prevalent neoplastic bone tumor, with an occurrence of 0.79/100,000/year. The biological presentation of this cancer fluctuates extensively, depending on the grade and anatomical location. Since chondrosarcoma is predominantly resistant to conventional chemo- and radiation therapy, surgical resection remains the sole curative treatment, although at present new treatment modalities are under investigation.

On the importance of considering disease subtypes: Earliest detection of a parosteal osteosarcoma? Differential diagnosis of an osteosarcoma in an Anglo-Saxon female

A case of potentially dedifferentiated parosteal osteosarcoma was found in the proximal humerus of an adult female buried in the late Anglo-Saxon cemetery of Cherry Hinton, Cambridgeshire, UK. Key features include a large, dense, lobulated mass attached to the medial metaphysis of the proximal humerus by a broad-based attachment, accompanied by cortical destruction and widespread spiculated periosteal reaction. Radiographic images confirm medullary involvement, lack of continuity between the cortex and external mass, a radiolucent cleavage plane and possible radiolucent zones within the bony masses. Differential diagnoses considered include osteochondroma, myositis ossificans, fracture callus, as well as the primary malignancies of osteosarcoma and chondrosarcoma, and their various subtypes. The macroscopic and radiographic analysis of the tumor is described and discussed within clinical and paleopathological contexts. One of only 19 uncontested examples of osteosarcoma from past human populations, most of which remain unconfirmed, this case represents what we believe to be the earliest, and probably singular, bioarcheological example of parosteal osteosarcoma in human history.

Bony metastases following complete resection of periosteal chondrosarcoma

Periosteal chondrosarcoma (PC) is a rare low-grade malignant cartilaginous tumor originating on the bone surface. Wide surgical resection is the recommended treatment. Prognosis is usually good if surgery is adequate. Metastasis is late and very rare. We present the clinical, radiographic, and pathological features of a PC accompanied with fibular cortical invasion in a 30-year-old woman. Wide resection was performed at presentation, but a whole-body positron emission tomography/computed tomography (PET/CT) examination 10 months after operation showed multiple bone metastases (MBM) especially in the spine, pelvis, bilateral femurs, and humeri without local recurrence. To the best of our knowledge, the present report is the first concerning a PC with so extensive postoperative MBM but without local recurrence.

Periosteal chondrosarcoma: a histopathological and molecular analysis of a rare chondrosarcoma subtype

AIMS

Periosteal chondrosarcoma is a rare, malignant cartilage-forming neoplasm originating from the periosteal surface of bone. We collected 38 cases from the archives of the Netherlands Committee on Bone Tumours, with the aim of studying histological features and evaluating the involvement of isocitrate dehydrogenase 1 (IDH1), EXT, Wnt/β-catenin, the pRB pathway (CDK4 and p16), and the TP53 pathway (p53 and MDM2).

METHODS AND RESULTS

Histology showed a moderately cellular matrix with mucoid-myxoid changes and, in 42% of cases, formation of a neocortex. Occasional intramedullary extension (26%) and subsequent host bone entrapment (40%) were seen. Histological grading revealed grade 1 (53%) and grade 2 (45%). The EXT1 protein was normally expressed, and mutations in IDH1 were observed in only 15% of cases. pRb signalling was deregulated by loss of p16 expression in 50% of cases, and Wnt signalling was lost in 89%. No alterations were found in CDK4, p53, or MDM2.

CONCLUSIONS

We report the first large histological and molecular study on periosteal chondrosarcoma showing that histopathological examination and molecular aberrations do not predict prognosis. Although the mutation frequency of IDH1 was low, we confirm the supposed relationship with central chondrosarcoma. Moreover, we identify loss of canonical Wnt signalling and deregulation of pRb signalling as possible events contributing to its histogenesis.

The presentation, treatment and outcome of periosteal chondrosarcoma in the Netherlands

In this case study, we describe the clinical presentation and treatment of 36 patients with periosteal chondrosarcoma collected over a 59-year period by the archive of the Netherlands Committee on Bone Tumours. The demographics, clinical presentation, radiological features, treatment and follow-up are presented with the size, location, the histological grading of the tumour and the survival. We found a slight predominance of men (61%), and a predilection for the distal femur (33%) and proximal humerus (33%). The metaphysis was the most common site (47%) and the most common presentation was with pain (44%). Half the tumours were classified histologically as grade 1. Pulmonary metastases were reported in one patient after an intra-lesional resection. A second patient died from local recurrence and possible pulmonary and skin metastases after an incomplete resection. It is clearly important to make the diagnosis appropriately because an incomplete resection may result in local recurrence and metastatic spread. Staging for metastatic disease is recommended in grade II or III lesions. These patients should be managed with a contrast-enhanced MRI of the tumour and histological confirmation by biopsy, followed by en-bloc excision.

The imaging of cartilaginous bone tumours. II. Chondrosarcoma

Chondrosarcoma is the third most common primary malignant bone tumour. There are various histological subtypes of chondrosarcomas, of which conventional intramedullary chondrosarcoma is by far the most common. Rarer sub-types include clear cell chondrosarcoma, myxoid chondrosarcoma, mesenchymal chondrosarcoma and dedifferentiated chondrosarcoma. Chondrosarcoma is also classified into central, peripheral and periosteal, dependent upon the lesion site, and into primary chondrosarcoma if the lesion arises de novo and secondary chondrosarcoma if the tumour arises in a pre-existing lesion. The various subtypes of chondrosarcoma have characteristic imaging features that may aid diagnosis and may guide biopsy, therefore potentially preventing misdiagnosis. The aim of this article is to provide an overview of the pertinent clinical and imaging findings of the different forms of chondrosarcoma.

Chondrosarcomas revisited

Chondrosarcomas are malignant bone tumors with pure hyaline cartilage differentiation; myxoid changes, calcification, or ossification may be present. Several subtypes of chondrosarcomas exist. Behavior patterns vary, ranging from slow-growing nonmetastasizing lesions to aggressive metastasizing sarcomas. Symptoms are usually mild, with duration ranging from several months to years, and usually consist of persistent, dull, aching pain or palpable masses. Radiographic findings include bone expansion with cortical thickening, radiolucent areas with variably distributed punctate or ring-like matrix calcifications, cortical erosion or destruction, endosteal scalloping, and scant or absent periosteal reaction; extension into the soft tissue may be present. Histological differential diagnosis from benign cartilaginous lesions can be achieved by increased cellularity, enlarged plump nuclei, binucleated cells, hyperchromatic nuclear pleomorphism, and permeation of cortical or medullary bone. Atypia is usually mild to moderate; necrosis and mitoses can be seen, particularly in high-grade lesions. Adequate surgery is the mainstay of treatment. High-grade and pelvic chondrosarcomas are best managed with wide resection. Because of the low metastatic potential and low local recurrence rate noted with intralesional surgery, low-grade chondrosarcomas can be treated with curettage (with or without treatment of the defect cavity) with a local adjuvant, such as phenol or cryotherapy. Adjuvant chemotherapy may be considered for mesenchymal and dedifferentiated chondrosarcomas. Radiation therapy can be considered after incomplete resection or if resection is not feasible or would cause unacceptable morbidity.

Intramedullary Chondrosarcoma of Proximal Humerus

Primary chondrosarcoma is the third most frequent primary malignancy of bone after myeloma and osteosarcoma. It is ranging from slow growing nonmetastasising lesions to highly aggressive lesions. We report a case of primary intramedullary chondrosarcoma of proximal humerus. A 60-year-old female presented with pain and hard swelling involving the left arm for 5 months. Radiograph showed a lucent expansile intramedullary lesion with matrix calcification and associated soft tissue mass. CT confirmed the finding. MRI showed a lobulated lesion which is hyperintense on T2WI with low signal fibrous septae. Increased tracer uptake was seen on bone scan. Histopathology confirmed the radiology diagnosis. The patient underwent wide resection and endoprosthetic reconstruction of proximal humerus.

Imaging of primary malignant bone tumors (nonhematological)

Primary malignant bone tumors are uncommon and are diagnosed typically based on radiographic and microscopic findings combined with clinical and demographic features. CT and MR imaging scans are useful in further staging the tumors by determining intraosseous and extraosseous spread.

Imaging characteristics of primary osteosarcoma: nonconventional subtypes

Osteosarcoma (OS) is a common primary malignant tumor of bone that produces osteoid matrix. According to the World Health Organization, OS of bone is classified into eight subtypes with distinct biologic behaviors and clinical outcomes: conventional, telangiectatic, small cell, low-grade central, secondary, parosteal, periosteal, and high-grade surface. Imaging plays a crucial role in the diagnosis of each subtype of OS and ultimately in patients' survival because the diagnosis is based on a combination of histopathologic and imaging features. Conventional OS is the most common subtype of OS and is readily identified at radiography as an intramedullary mass with immature cloudlike bone formation in the metaphyses of long bones. The imaging features of less common subtypes of primary OS are variable and frequently overlap with those of multiple benign and malignant entities, creating substantial diagnostic challenges. For accurate diagnosis, it is important to be aware of radiographic and cross-sectional imaging features that allow differentiation of each nonconventional subtype of OS from its mimics.

Periosteal chondrosarcoma of the foot: a case report

A 19-year-old girl presented with painless swelling of the first left toe of 6 years' duration. Magnetic resonance imaging (MRI) of the lesion demonstrated a soft tissue mass adjacent to the surface of the bone with slight erosion of the underlying cortex. Surgical excision was performed and the histopathological diagnosis was low-grade periosteal chondrosarcoma, which is quite uncommon in this location.

Periosteal chondrosarcoma

OBJECTIVE

The purpose of this article is to identify the typical imaging features of periosteal chondrosarcoma on radiography, CT, and MRI.

CONCLUSION

Periosteal chondrosarcoma is a rare low-grade malignant cartilaginous tumor arising from the external surface of bone. Imaging features are often specific. Recognizing periosteal chondrosarcoma and differentiating it from other surface tumors is of capital importance because the prognosis is excellent after adequate local surgery alone.

Mandibular periosteal (juxtacortical) chondrosarcoma

Periosteal (juxtacortical) chondrosarcoma (PC) is a well-differentiated malignant cartilage-forming tumor arising from the external bone surface, especially in long bones. The therapy of choice is en-bloc resection and, in general, its prognosis is good. This paper reports a rare case of PC affecting the mandible of a 41-year-old man. The lesion presented as a slow-growing-painless swelling that lasted 2 months. Computed tomography scan showed a tumoral mass arising from the external bone surface, extending into the adjacent soft tissue presenting patchy regions of popcorn-like calcifications. A final diagnosis of PC (grade II) was rendered after biopsy. Hemimandibulectomy was undertaken followed by complementary radiotherapy with 70 Gy. Although no episodes of recurrence or metastasis had been noticed after 18 months of follow-up, the patient died and causa mortis could not be established.

The clinical approach towards chondrosarcoma

This review provides an overview of the histopathology, classification, diagnostic procedures, and therapy of skeletal chondrosarcoma. Chondrosarcomas that arise de novo are primary chondrosarcomas, whereas chondrosarcomas developing superimposed on pre-existing benign cartilage neoplasms such as enchondromas or osteochondromas are referred to as secondary chondrosarcomas. Conventional chondrosarcomas can be categorized according to their location in bone into central, peripheral, and juxtacortical chondrosarcomas. Histological grading is related to prognosis; however, it is also subject to interobserver variability. Rare subtypes of chondrosarcoma, including dedifferentiated, mesenchymal, and clear cell chondrosarcoma, are discussed as well. Magnetic resonance imaging is necessary to delineate the extent of the intraosseous and soft tissue involvement preoperatively. Computed tomography is especially recommended in the pelvis and other flat bones where it may be difficult to discern the pattern of bone destruction and the presence of matrix mineralization. Wide, en-bloc excision is the preferred surgical treatment in intermediate- and high-grade chondrosarcoma. In low-grade chondrosarcoma confined to the bone, extensive intralesional curettage followed by local adjuvant treatment and filling the cavity with bone graft has promising long-term clinical results and satisfactory local control. Chondrosarcomas are relatively radiotherapy resistant; therefore, doses >60 Gy are needed in attempts to achieve local control after incomplete resection. Irradiation with protons or other charged particles seems beneficial in this curative situation. Chemotherapy is only possibly effective in mesenchymal chondrosarcoma, and is of uncertain value in dedifferentiated chondrosarcoma. Potential new systemic treatment targets are being discussed.

Enchondroma protuberans of the hand

OBJECTIVE

Enchondroma protuberans is a rare tumor that arises from an intramedullary enchondroma with an exophytic growth pattern. The purpose of this study was to describe imaging findings of this disease that were obtained using both radiography and MRI.

CONCLUSION

It is necessary to understand the characteristic imaging findings of enchondroma protuberans to avoid misdiagnosis. When radiography does not allow a clear diagnosis of enchondroma protuberans, MRI may be helpful for diagnosis.

Imaging of chondrosarcomas

Chondrosarcoma is the commonest primary sarcoma of bone in adults, with a male predominance. Patients are usually between 30 and 70 years old. Clinical symptoms are pain and tenderness with or without a mass, the average duration of symptoms being 1–2 years, but growth may be very slow, especially for pelvic tumours [1]. Chondrosarcomas characteristically produce coalescent cartilage lobules of various size. The center often becomes necrotic or cystic [1].