Chondrosarcoma: MR imaging with pathologic correlation

Neoplastic and Non-neoplastic Bone Lesions of the Knee

Numerous anatomical variants are described around the knee, many of which look like bony lesions, so it is important to know them to avoid unnecessary complementary tests and inadequate management. Likewise, several alterations in relation to normal development can also simulate bone lesions.However, numerous pathologic processes frequently affect the knee, including traumatic, inflammatory, infectious, and tumor pathology. Many of these entities show typical radiologic features that facilitate their diagnosis. In other cases, a correct differential diagnosis is necessary for proper clinical management.Despite the availability of increasingly advanced imaging techniques, plain radiography is still the technique of choice in the initial study of many of these pathologies. This article reviews the radiologic characteristics of tumor and nontumor lesions that may appear around the knee to make a correct diagnosis and avoid unnecessary complementary radiologic examinations and inadequate clinical management.

Chondrosarcoma of Iliac Bone Imaging Spectrum With Histopathological Correlation: A Case Report

Chondrosarcoma is a rare form of carcinoma that originates in the cells of cartilage, the flexible tissue that cushions the joints and gives structure to various parts of the body. This malignant tumour primarily affects adults and is most commonly found in the bones of the arms, legs, pelvis, and ribs. The severity and prognosis of chondrosarcoma can vary widely depending on factors such as tumour size, location, and grade. We are reporting a case of an 83-year-old male patient who presented with swelling over the left hip joint. A mass was detected on radiograph and ultrasound that was further characterized using contrast-enhanced CT and MRI. Imaging findings suggested chondrosarcoma. The patient was diagnosed on histopathological examination.

Chondrosarcoma of the hyoid bone: a case of mistaken identity in the submandibular region

We describe a case of woman in her 60s who presented with a painless mass in her left submandibular region that biopsies and imaging suggested was a pleomorphic adenoma. Intraoperative findings showed a submandibular mass originating from the hyoid bone, and subsequent histopathological examination showed a grade 2 chondrosarcoma of the hyoid bone. Chondrosarcomas in the head and neck region are uncommon and presentations in the hyoid bone are very rare with only approximately 27 previously published cases. Presentations that pose as more benign pathology can cause diagnostic dilemmas for clinicians.

Machine learning and magnetic resonance imaging: Differentiating benign from malignant osseous tumors

Radiomics and machine learning applied to the isolated cartilaginous bone lesion on magnetic resonance imaging (MRI) is increasingly useful to distinguish malignant versus benign bone lesions, to determine whether repetitive imaging over time, to determine dynamic expansion, or immediate excisional biopsy are indicated.

Grade 1 and 2 Chondrosarcomas of the Chest Wall: CT Imaging Features and Review of the Literature

The purpose of our retrospective article is to review the CT imaging features of chondrosarcomas of the chest wall with pathologic correlation. For 26 subjects with biopsy-proven chondrosarcomas of the chest wall, two musculoskeletal radiologists retrospectively reviewed 26 CT scans in consensus. Descriptive statistics were performed. The mean tumor size was 57 mm. Twenty (20/26, 77%) chondrosarcomas were located in the ribs and six (6/26, 23%) in the sternum. The majority were lytic (19/26, 73%) with <25% calcification (15/26, 58%), and with a soft tissue mass (22/27, 85%). In this study CT features of grade 1 chondrosarcoma overlapped with those of grade 2 tumors. In conclusion, chondrosarcomas of the chest wall are generally lytic with an associated soft tissue mass, showing little calcified matrix and low-to-intermediate grade.

Imaging features of laryngeal chondrosarcomas: A case series and systematic review

BACKGROUND AND PURPOSE

To comprehensively summarize the characteristics of radiological findings of laryngeal conventional chondrosarcomas.

METHODS

We included patients with pathologically proven laryngeal conventional chondrosarcomas with CT and /or MRI, including 41 cases from 31 publications recruited after a systematic review and 14 cases from our institution. Two board-certified radiologists reviewed and evaluated all the radiological images. The relationship between pathological grade and radiological findings was analyzed.

RESULTS

The median long diameter of the lesion was 3.1 cm (range, 1.5-8.5 cm). The most common location was the cricoid (74.5%), followed by the thyroid (12.7%), cricoid and thyroid (7.3%), and arytenoid (5.5%). All lesions showed well-defined margins. Cortical defect/expansion (98.0%), internal low density (89.6%), and calcification (95.8%) with homogeneous and scarce contrast enhancement on contrast-enhanced CT (85.3%) were frequently observed. All cases showed high signal on T2-weighted imaging, low signal on T1-weighted imaging (T1WI), and heterogeneous and mild contrast enhancement on postcontrast T1WI. No significant differences were found between the pathological grades and radiological findings.

CONCLUSIONS

In our summary of comprehensive CT and MRI findings of laryngeal conventional chondrosarcomas, we found that the knowledge of these radiological features may facilitate prompt diagnosis and appropriate management.

Chondrogenic Bone Tumors: The Importance of Imaging Characteristics

BACKGROUND

 Chondrogenic tumors are the most frequent primary bone tumors. Malignant chondrogenic tumors represent about one quarter of malignant bone tumors. Benign chondrogenic bone tumors are frequent incidental findings at imaging. Radiological parameters may be helpful for identification, characterization, and differential diagnosis.

METHODS

 Systematic PubMed literature research. Identification and review of studies analyzing and describing imaging characteristics of chondrogenic bone tumors.

RESULTS AND CONCLUSIONS

 The 2020 World Health Organization (WHO) classification system differentiates between benign, intermediate (locally aggressive or rarely metastasizing), and malignant chondrogenic tumors. On imaging, typical findings of differentiated chondrogenic tumors are lobulated patterns with a high signal on T2-weighted magnetic resonance imaging (MRI) and ring- and arc-like calcifications on conventional radiography and computed tomography (CT). Depending on the entity, the prevalence of this chondrogenic pattern differs. While high grade tumors may be identified due to aggressive imaging patterns, the differentiation between benign and intermediate grade chondrogenic tumors is challenging, even in an interdisciplinary approach.

KEY POINTS

  · The WHO defines benign, intermediate, and malignant chondrogenic bone tumors. · Frequent benign tumors: osteochondroma and enchondroma; Frequent malignant tumor: conventional chondrosarcoma. · Differentiation between enchondroma versus low-grade chondrosarcoma is challenging for radiologists and pathologists. · Pain, deep scalloping, cortical destruction, bone expansion, soft tissue component: favor chondrosarcoma. · Potential malignant transformation of osteochondroma: progression after skeletal maturity, cartilage cap thickness (> 2 cm adult; > 3 cm child). · Potentially helpful advanced imaging methods: Dynamic MRI, texture analysis, FDG-PET/CT.

CITATION FORMAT

· Engel H, Herget GW, Füllgraf H et al. Chondrogenic Bone Tumors: The Importance of Imaging Characteristics. Fortschr Röntgenstr 2021; 193: 262 - 274.

Can MRI differentiate between atypical cartilaginous tumors and high-grade chondrosarcoma? A systematic review

Background and purpose - Adequate staging of chondroid tumors at diagnosis is important as it determines both treatment and outcome. This systematic review provides an overview of MRI criteria used to differentiate between atypical cartilaginous tumors (ACT) and high-grade chondrosarcoma (HGCS).Patients and methods - For this systematic review PubMed and Embase were searched, from inception of the databases to July 12, 2018. All original articles describing MRI characteristics of pathologically proven primary central chondrosarcoma and ACT were included. A quality appraisal of the included papers was performed. Data on MRI characteristics and histological grade were extracted by 2 reviewers. Meta-analysis was performed if possible. The study is registered with PROSPERO, CRD42018067959.Results - Our search identified 2,132 unique records, of which 14 studies were included. 239 ACT and 140 HGCS were identified. The quality assessment showed great variability in consensus criteria used for both pathologic and radiologic diagnosis. Due to substantial heterogeneity we refrained from pooling the results in a meta-analysis and reported non-statistical syntheses. Loss of entrapped fatty marrow, cortical breakthrough, and extraosseous soft tissue expansion appeared to be present more often in HGCS compared with ACT.Interpretation - This systematic review provides an overview of MRI characteristics used to differentiate between ACT and HGCS. Future studies are needed to develop and assess more reliable imaging methods and/or features to differentiate ACT from HGCS.

Skull Base Chordomas and Chondrosarcomas

Skull base chordomas account for less than 0.2% and chondrosarcomas for less than 0.15% of all intracranial tumors. Although their clinical and imaging presentations are similar, they derive from different origins. Chordomas arise from embryonic remnants of the primitive notochord and chondrosarcomas from primitive mesenchymal cells or from the embryonic rest of the cranial cartilaginous matrix. Both entities are characterized by infiltration and destruction of the surrounding bone and soft tissue and a high locoregional recurrence rate. Chondrosarcomas, when treated with similar complex strategies, display a much better prognosis than chordomas. The overall survival is approximately 65% for chordomas and 80% for chondrosarcomas at 5 years and 30 and 50%, respectively, at 10 years. Chordomas are divided into the following 3 histological types: classical (conventional), chondroid, and dedifferentiated. Chondrosarcomas have conventional, mesenchymal, clear cell, and dedifferentiated subgroups. Both tumor entities often present with nonspecific symptoms, and headaches are the most reported initial symptom. Computed tomography and magnetic resonance imaging are required to determine the tumor localization and the extent of tumor growth. The treatment philosophy is to maximize tumor resection, minimize morbidity, and preserve function. Neurosurgical approaches commonly used for the resection of intracranial chordomas and chondrosarcomas are transsphenoidal, transbasal, cranio-orbitozygomatic, transzygomatic extended middle fossa, transcondylar, and transmaxillary approaches. Chordomas and chondrosarcomas are not sensitive to chemotherapy and there are no approved drugs for their treatment. The present treatment concept is a combination of surgical resection with a maximal excision and preserving patients' quality of life by adjuvant radiotherapy for both chordomas and chondrosarcomas.

MR Imaging of Primary Chest Wall Neoplasms

Primary chest wall neoplasms are uncommon and comprise a heterogeneous group of lesions that may be challenging to classify and diagnose. These tumors may be primary or secondary, malignant or benign, and arise from cartilaginous/osseous structures or soft tissues. The role of magnetic resonance (MR) imaging in the evaluation of chest wall tumors continues to expand given its superior soft tissue contrast relative to computed tomography. MR imaging can facilitate differentiation of neoplasms from normal chest wall structures and other disease processes due to infection and inflammation, and can fully characterize abnormalities by demonstrating the various internal components of complex lesions. It is important that radiologists be able to identify key features of primary chest wall neoplasms on MR imaging to provide focused differential diagnoses and guide patient management.

Chondrosarcoma of the para-acetabulum: correlation of imaging features with histopathological grade

OBJECTIVE

To evaluate the computed tomography (CT) and magnetic resonance (MR) imaging features of para-acetabular chondrosarcoma (CS) and assess the difference between low-grade CS (LGCS) and high-grade CS (HGCS).

MATERIALS AND METHODS

Thirty-one patients with histopathologically confirmed central para-acetabular CSs (6 LGCS and 25 HGCS) were retrospectively reviewed. Image features were evaluated for the following: cortical destruction, tumor border and pattern, calcification mode, soft-tissue mass, density/signal intensity, peritumoral edema, acetabular (cartilage) destruction, diffuse signal changes in acetabulum, mass inside hip joint, femoral head involvement, enhancement manifestations and the maximum length of the tumor. These image features between LGCS and HGCS were also assessed.

RESULTS

The most common CT and/or MR findings included cortical destruction, punctate, ring-and-arc and linear calcification, soft-tissue mass, lobulated border, high signal intensity with low signal septa on T2-weighted image, peritumoral edema, hip joint infiltration, peripheral and septal enhancement on post-enhanced MR image. Statistical analysis showed that the image features, such as cortical destruction, soft-tissue mass, hip joint infiltration and tumor size were significantly different between LGCS and HGCS (p < 0.05).

CONCLUSION

The characteristic radiological features of para-acetabular CSs are osteolytic lesions with cortical destruction, soft-tissue mass, lobulated border, calcification, and high signal intensity with low signal septa on T2-weighted MR image, peripheral and septal enhancement on post-enhanced MR image. Cortical destruction, soft-tissue mass, hip joint infiltration and tumor size can differentiate HGCS from LGCS.

Imaging Evaluation of Malignant Chest Wall Neoplasms

Neoplasms of the chest wall are uncommon lesions that represent approximately 5% of all thoracic malignancies. These tumors comprise a heterogeneous group of neoplasms that may arise from osseous structures or soft tissues, and they may be malignant or benign. More than 50% of chest wall neoplasms are malignancies and include tumors that may arise as primary malignancies or secondarily involve the chest wall by way of direct invasion or metastasis from intrathoracic or extrathoracic neoplasms. Although 20% of chest wall tumors may be detected at chest radiography, chest wall malignancies are best evaluated with cross-sectional imaging, principally multidetector computed tomography (CT) and magnetic resonance (MR) imaging, each of which has distinct strengths and limitations. Multidetector CT is optimal for depicting bone, muscle, and vascular structures, whereas MR imaging renders superior soft-tissue contrast and spatial resolution and is better for delineating the full extent of disease. Fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT is not routinely performed to evaluate chest wall malignancies. The primary functions of PET/CT in this setting include staging of disease, evaluation of treatment response, and detection of recurrent disease. Ultrasonography has a limited role in the evaluation and characterization of superficial chest wall lesions; however, it can be used to guide biopsy and has been shown to depict chest wall invasion by lung cancer more accurately than CT. It is important that radiologists be able to identify the key multidetector CT and MR imaging features that can be used to differentiate malignant from benign chest lesions, suggest specific histologic tumor types, and ultimately guide patient treatment. (©)RSNA, 2016.

Enchondroma versus Chondrosarcoma in Long Bones of Appendicular Skeleton: Clinical and Radiological Criteria-A Follow-Up

As of today two types of cartilage tumors remain a challenge even for the orthopedic oncologist: enchondroma (E), a benign tumor, and chondrosarcoma (LGC), a malignant and low aggressiveness tumor. A prospective study of 133 patients with a cartilaginous tumor of low aggressiveness in the long bones of the appendicular skeleton was done to prove this difficult differential diagnosis. Parameters including medical history and radiological and nuclear imaging were collected and compared to the result of the biopsy. A scale of aggressiveness was applied to each patient according to the number of aggressiveness episodes present. A comparison of the results of the biopsy with the initial diagnosis made by the orthopedic oncologist based solely on clinical data and imaging tests was also made. Finally, a management algorithm for these cases was proposed. A statistical significance for LGC resulted from the parameter as follows: pain on palpation, involvement of cortical in either the CT or MRI, and Tc99 bone scan uptake equal or superior to anterosuperior iliac crest. In our series, a tumor scoring 5 points or higher in the scale of aggressiveness can have 50% more chance of being LGC. When compared with the gold standard (the biopsy), surgeon's initial judgement showed a sensitivity of 73.5% and a specificity of 94.1%.

RadPath: A Web-based System for Integrating and Correlating Radiology and Pathology Findings During Cancer Diagnosis

RATIONALE AND OBJECTIVES

The current paradigm of cancer diagnosis involves uncoordinated communication of findings from radiology and pathology to downstream physicians. Discordance between these findings can require additional time from downstream users to resolve, or given incorrect resolution, may adversely impact treatment decisions. To mitigate this problem, we developed a web-based system, called RadPath, for correlating and integrating radiology and pathology reporting.

MATERIALS AND METHODS

RadPath includes interfaces to our institution's clinical information systems, which are used to retrieve reports, images, and test results that are structured into an interactive compendium for a diagnostic patient case. The system includes an editing interface for physicians, allowing for the inclusion of additional clinical data, as well as the ability to retrospectively correlate and contextualize imaging findings following pathology diagnosis.

RESULTS

During pilot deployment and testing over the course of 1 year, physicians at our institution have completed 60 RadPath cases, requiring an average of 128 seconds from a radiologist and an average of 93 seconds from a pathologist per case. Several technical and workflow challenges were encountered during development, including interfacing with diverse clinical information systems, automatically structuring report contents, and determining the appropriate physicians to create RadPath summaries. Reaction to RadPath has been positive, with users valuing the system's ability to consolidate diagnostic information.

CONCLUSIONS

With the increasing complexity of medicine and the movement toward team-based disease management, there is a need for improved clinical communication and information exchange. RadPath provides a platform for generating coherent and correlated diagnostic summaries in cancer diagnosis with minimal additional effort from physicians.

Imaging-histologic discordance at percutaneous biopsy of the lung

RATIONALE AND OBJECTIVES

The purpose of this study was to quantify the degree of imaging-histologic discordance in a cohort of patients undergoing computed tomography (CT)-guided lung biopsy for focal lung disease.

MATERIALS AND METHODS

A retrospective review was performed of 186 patients who underwent percutaneous lung biopsy of a parenchymal lesion at our institution between January and December 2009. Diagnostic radiology reports of CT or positron emission tomography-CTs performed before biopsy were used to classify the lesion as malignant or benign by five readers. Pathology reports of the biopsied lesions were classified by three readers. Inter-reader agreement and imaging-histologic concordance were quantified using kappa statistics. Discordant benign cases were then revisited to determine downstream effects.

RESULTS

Inter-reader agreement on report content was substantial or almost perfect with kappas >0.783. Kappas for concordance were as follows: malignant (0.448), primary lung cancer (0.517), metastatic disease to lung (0.449), benign (0.510), and overall agreement (0.381). Of the twelve discordant benign cases that were revisited, four were found to be false negatives, resulting in a delay in diagnosis.

CONCLUSIONS

Our study of imaging-histologic discordance in percutaneous biopsy of lung lesions supports the need for imaging report standardization and improved integration and communication between the fields of radiology and pathology.

Mesenchymal chondrosarcoma of the right buccal region: A case report and review of the literature

Extraskeletal mesenchymal chondrosarcoma (EMCS) is a rare malignant cartilaginous tumor arising from the soft tissues. The most common areas of extraskeletal origin are the lower extremities, the orbits and the central nervous system, among others. In this study, the case of primary EMCS arising from the right buccal region in a 26-year old female is presented. Histological and immunohistochemical analysis confirmed the diagnosis of EMCS. Subseqently, the patient was treated with radical surgery, but declined chemotherapy or radiotherapy, which was recommended. One year after surgery, no recurrence had been identified in the patient. To the best of our knowledge, only one case of primary EMCS of the buccal region has been reported previously. In the current study, a case of primary EMCS of the buccal region is presented.

Preoperative radiographic and histopathologic evaluation of central chondrosarcoma

BACKGROUND

Distinguishing grade 1 chondrosarcoma from grade 2 chondrosarcoma is critical both for planning the surgical procedure and for predicting the outcome. We aimed to review the preoperative radiographic and histologic findings, and to evaluate the reliability of preoperative grading.

METHODS

We retrospectively reviewed the medical records of 17 patients diagnosed with central chondrosarcoma at our institution between 1996 and 2011. In these cases, we compared the preoperative and postoperative histologic grades, and evaluated the reliability of the preoperative histologic grading. We also assessed the preoperative radiographic findings obtained using plain radiography, computed tomography (CT), and magnetic resonance imaging (MRI).

RESULTS

Preoperative histologic grade was 1 in 12 patients, 2 in 4 patients, and 3 in 1 patient. However, 6 of the 12 cases classified as grade 1 before surgery were re-classified as grade 2 postoperatively. In the radiographic evaluation, grade 1 was suspected by the presence of a ring-and-arc pattern of calcification on plain radiography and CT and entrapped fat and ring-and-arc enhancement on MRI. Grades 2 and 3 were suspected by the absence of calcification and the presence of cortical penetration and endosteal scalloping on plain radiography and CT, as well as soft-tissue mass formation on MRI.

CONCLUSION

Although the combination of radiographic interpretation and histologic findings may improve the accuracy of preoperative grading in chondrosarcoma, the establishment of a standard evaluation system with the histologic and radiographic findings and/or the development of new biologic markers are necessary for preoperative discrimination of low-grade chondrosarcoma from high-grade chondrosarcoma.

MR differentiation of low-grade chondrosarcoma from enchondroma

PURPOSE

To evaluate magnetic resonance (MR) imaging for the discrimination between low-grade chondrosarcoma and enchondroma.

MATERIALS AND METHODS

MR images of 34 patients who were confirmed with low-grade chondrosarcoma or enchondroma were retrospectively reviewed. After review of medical records, MR findings in 18 patients with low-grade chondrosarcoma and 16 patients with enchondroma were compared. MR images were retrospectively reviewed for the lesion location (central or eccentric; epiphysis, metaphysic, or diaphysis), margin, contour, mineralized matrix, endosteal scalloping, cortical expansion, cortical destruction, soft tissue mass formation, and periosteal reaction. Signal intensity, the patterns of contrast enhancement (unilocular or multilobular), soft tissue mass, and adjacent abnormal bone marrow and soft tissue signal were also reviewed. Statistical analysis was performed with chi-square test.

RESULTS

The patients with low-grade chondrosarcoma had a significantly higher incidence of MR findings (P<.05): predominantly intermediate signal on T1-weighted images [72% (13/18) in low-grade chondrosarcoma vs. 25% (4/16) in enchondroma], multilocular appearance on contrast-enhanced T1-weighted images [83% (15/18) vs. 44% (7/16)], cortical destruction [33% (6/18) vs. 0% (0/16)], a soft tissue mass [28% (5/18) vs. 0% (0/16)], adjacent bone marrow and soft tissue abnormal signal [22% (4/18) vs. 0% (0/16)], and an involvement of the epiphysis or flat bone [56% (10/18) vs. 19% (3/16)].

CONCLUSION

MR imaging shows helpful features for differentiating low-grade chondrosarcoma from enchondroma.

Malignant primary chest wall neoplasms: a pictorial review of imaging findings

Malignant primary chest wall neoplasms (MCWN) are uncommon. Although benign chest wall neoplasms are most commonly asymptomatic, MCWN typically manifest as painful, fast growing masses. While the imaging features of malignant masses can be nonspecific, knowledge of the typical radiologic manifestations of MCWN may suggest a specific diagnosis. We review imaging features of the most common MCWN with images collected at an outpatient academic oncologic center.

OBJECTIVE

While the imaging features of patients with malignant masses can be nonspecific, knowledge of the typical radiologic manifestations of MCWN may suggest a specific diagnosis. We review distinguishing imaging features of the most common MCWN, including epithelial and mesenchymal malignancies, with images collected at an outpatient oncologic center.

CONCLUSION

Chest wall neoplasms encompass 5% of all thoracic tumors, with nearly half of chest wall neoplasms being malignant. Out of these malignant neoplasms, 50% are primary and the commonest one is chondrosarcoma. Although distinguishing imaging features may suggest a specific diagnosis in the majority of MCWN, most affected patients undergo biopsy for a definitive diagnosis.

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.

Imaging of soft tissue and osseous sarcomas of the extremities

Soft tissue and osseous sarcomas of the extremities are uncommon malignancies that represent very important diagnostic entities because of their aggressive nature. Radiologic investigations, including plain film, computed tomography, contrast-enhanced magnetic resonance imaging; scintigraphy, ultrasound, and positron emission tomography-computed tomography, play critical roles in providing a differential, establishing the diagnosis, demonstrating prognostic characteristics, and tailoring tumor treatment. The purpose of this review is to describe the most common soft tissue and osseous sarcomas of the extremities, with emphasis on their plain film and magnetic resonance imaging characteristics with the aim of aiding the reader to accurately describe the important imaging features and generate an appropriate differential diagnosis to aid the referring clinician with prompt appropriate management and treatment.

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.

Radiology of chest wall masses

OBJECTIVE

The purpose of this article is to highlight the role of radiography, CT, PET/CT, and MRI in the diagnosis and management of chest wall lesions. Chest wall masses are caused by a spectrum of clinical entities. The lesions highlighted in this selection of case scenarios include neoplastic, inflammatory, and vascular lesions.

CONCLUSION

Imaging evaluation with radiography, CT, MRI, and PET/CT plays an important role in the accurate diagnosis of chest wall lesions. It can also facilitate percutaneous biopsy, when it is indicated. Imaging enables accurate staging and is a key component of treatment planning for chest wall masses.

Ice-cream cone reconstruction of the pelvis: a new type of pelvic replacement

Endoprosthetic replacement of the pelvis is one of the most challenging types of limb-salvage surgery, with a high rate of complications. In an attempt to reduce this and build greater versatility into the reconstruction process, a new type of pelvic endoprosthesis was developed in 2003, based on the old McKee-Farrar prosthesis. This study reviews the outcomes in 27 patients who had an ice-cream cone pelvic prosthesis inserted at two different specialist bone tumour centres in the United Kingdom over the past six years. The indications for treatment included primary bone tumours in 19 patients and metastatic disease in two, and six implants were inserted following failure of a previous pelvic reconstruction. Most of the patients had a P2+P3 resection as classified by Enneking, and most had resection of the ilium above the sciatic notch. The mean age of the patients at operation was 49 years (13 to 81). Complications occurred in ten patients (37.0%), of which dislocation was the most common, affecting four patients (14.8%). A total of three patients (11.1%) developed a deep infection around the prosthesis but all were successfully controlled by early intervention and two patients (7.4%) developed a local recurrence, at the same time as widespread metastases appeared. In one patient the prosthesis was removed for severe pain.

This method of treatment is still associated with high morbidity, but early results are promising. Complications are diminishing with increasing experience.

[Dedifferentiated chondrosarcoma: radiologic-pathologic correlation]

Dedifferentiated chondrosarcomas are highly malignant tumors characterized by conventional low-grade chondrosarcoma with abrupt transition to foci that have dedifferentiated into a higher-grade noncartilaginous more aggressive sarcoma. The dedifferentiated component, an osteosarcoma or fibrosarcoma, determines the prognosis. Its identification is key for management. A diagnosis of dedifferentiated chondrosarcoma should be suggested by the presence of "tumoral dimorphism" with cartilaginous component and aggressive lytic component invading adjacent soft tissues.

Integrated PET/CT in evaluating sarcomatous transformation in osteochondromas

AIM

To study the role of PET-CT in evaluating sarcomatous transformation in osteochondromas.

MATERIALS AND METHODS

This was a retrospective analysis of a prospective data base of 12 patients from 2005 to 2007 with a clinical diagnosis of an osteocartilaginous lesion who were referred for a FDG PET-CT study to evaluate for possible malignant transformation. Imaging was performed on a GE Discovery ST PET-CT system after intravenous injection of 370 MBq (10 mCi) of F-18 FDG.

RESULTS

Seven patients with histopathological evidence of a sarcomatous transformation to grade II chondrosarcoma showed moderate to high FDG uptake (SUV 3.3-6.9), whereas 1 patient with a dedifferentiated chondrosarcoma showed a focus of very intense uptake (SUV 11.4). Four patients with histopathological and/or clinical or follow-up diagnosis of a benign osteocartilaginous lesion showed low grade FDG uptake (SUV 0.8-1.3). FDG uptake was also noted in an asymptomatic osteochondroma which on histopathology revealed a grade II chondrosarcoma.

CONCLUSIONS

Whole body FDG PET-CT is an important adjunct to conventional morphologic imaging in evaluating suspected malignant transformation in osteochondromas. Increased glucose metabolism can help diagnose sarcomatous transformation at the suspected sites as well as detect early malignant change at clinically unsuspected sites. Moreover, its ability to detect a focus of dedifferentiation can be useful for prognostication and to plan adjuvant treatment. A small cohort limits statistically sound conclusions to be drawn from this study, however further prospective trials based on these findings can help explore the potential application of FDG PET-CT in this clinical condition.

Resection and reconstruction of an osteochondroma of the hallux: a review of benign bone tumors and a description of an unusual case

Osteochondroma, which is also known as exostosis, is the most common benign bone tumor. Although foot and hand surgeons frequently encounter the subungual exostosis, exostoses commonly localize to other areas of the skeleton as well. In this review, we describe the clinical and diagnostic imaging characteristics of benign bone tumors and, in particular, the osteochondroma and its surgical management. We also report the case of a patient who experienced an unusual pedal digital osteochondroma-like lesion.

LEVEL OF CLINICAL EVIDENCE

4.

MR imaging evaluation of disorders of the chest wall

Chest wall lesions constitute a diverse group of thoracic diseases, including those of soft tissue and osseous origin. MR imaging, with its superior tissue-resolving capability and multiplanar image acquisition, is an important tool for assessing chest wall lesions. In this article, the authors review common and uncommon diseases of the chest wall, with an emphasis on the MR imaging characteristics of these diseases. Among the diseases they discuss are diseases of the soft tissue including lipoma, hibernoma, liposarcoma, hemangioma, and lymphoma. They also examine diseases of the osseous thorax, including benign osseous tumors, fibrous dysplasia, and aneurysmal bone cyst. In addition, they discuss such malignant osseous tumors as osteosarcoma and Ewing's sarcoma.

Extraskeletal mesenchymal chondrosarcoma of the cervical meninx

We report a case of recurrent mesenchymal chondrosarcoma in the cervical paravertebral region that was diagnosed preoperatively by imaging studies. The tumor showed findings of a well-differentiated cartilaginous tumor with a characteristic pattern of calcifications on computed tomography (CT). However, it appeared as a soft tissue sarcoma of lower intensity than common cartilaginous tumors on T2-weighted magnetic resonance imaging (MRI). This discrepancy between CT and MRI was well correlated with pathological findings of mesenchymal chondrosarcoma and suggested this entity.

Primary chondrosarcoma in the skull of a dog

Chondrosarcoma of the skull is a rare primary malignant tumor that is slow-growing, but locally aggressive. A 5-year-old, golden retriever was presented to our hospital with a swelling in the left side of her head, and the swelling had slowly enlarged over the previous month. There were no significant changes on the neurological examination. A computed tomography scan revealed a large mass involving bone destruction and prominent matrix mineralization. T1-weighted magnetic resonance imaging showed a slightly low-signal intensity area and a T2-weighted image revealed marked, high-signal intensity. There was compression of the adjacent brain parenchyma. Histopathological examination confirmed the lesion to be a chondrosarcoma.

18Fluoro-deoxyglucose positron emission tomography evaluation of benign versus malignant osteochondromas: preliminary observations

OBJECTIVE

To determine the contribution of 18fluoro-deoxyglucose positron emission tomography (18FDG PET) in distinguishing benign from malignant osteochondromas.

MATERIALS AND METHODS

From 2000 to 2004, 10 patients (4 females, 6 males, 12 to 64 years old) with osteochondromas were referred for whole body PET by clinicians for metabolic evaluation before planned surgery for pain or cosmesis. Two PET readers and 1 pathologist, blinded to their diagnoses and imaging studies (except for radiographs), correlated results post surgery. The PET average and maximum standard uptake value (SUV) generated by computer for Regions of Interest and correlated with radiographs, were based on axial 3.37 mm thick, 3 x 3 mm pixel images. Since SUVs vary from site to site depending on scanning devices and techniques, a 2.0 maximum cutoff SUV separated benign and malignant osteochondromas based on our standard protocols and specific equipment (Siemens Ecat Exact Knoxville, Tenn) used with our prior oncological studies.

RESULTS

Results showed that no definitive statistical conclusions could be drawn due to the small number of patients involved, but they were, nevertheless, deemed promising.

CONCLUSIONS

The 18FDG whole body PET aided the identification of malignant osteochondromas, their local recurrence and metastases by both displaying and quantifying their metabolic activity. Although the current study is limited by a small cohort, which precludes statistical analysis, additional experience with PET analysis of osteochondromas may further support its value as a physiological parameter supplementing anatomically based imaging modalities most often used for their evaluation.

Influence of cryosurgery on treatment outcome of low-grade chondrosarcoma

Successfully managing low-grade chondrosarcomas with margins considered less than wide would minimize the need for extensive reconstruction. We report our experience using cryotherapy as an adjuvant to treat patients with low-grade intracompartmental chondrosarcomas. Ten consecutive patients had intralesional resections including curettage, cryo-surgery, and polymethylmethacrylate application. Eight of these patients required prophylactic skeletal stabilization. We retrospectively reviewed the outcomes for tumor recurrence, disease progression, and complications. The Musculo-skeletal Tumor Society rating scale was used to evaluate functional outcome, and the mean score was 27 points (range, 25-30 points). The mean age of the patients was 54.4 years (range, 29-83 years), and the average followup was 38.5 months (range, 24-60 months). Patients were treated for lesions of the femur (n = 3), humerus (n = 3), scapula (n = 2), tibia (n = 1), and acetabulum (n = 1). There was no evidence of recurrence or metastases. At the latest followup, all patients were well, however, one patient had hardware loosening. In this small group of patients, intralesional resection with adjuvant cryoablation provided an alternative to more radical procedures for low-grade intracompartmental chondrosarcoma.

MR imaging of tumors and tumor-like lesions of the hip

In conclusion, a wide variety of tumors and tumor-like conditions have a predilection for the hip. The imaging evaluation of these lesions begins with radiographs. Radiographs can depict the extent of disease; any characteristic calcifications; and osseous changes, such as remodeling,periosteal reaction, or destruction. MR imaging has emerged as the preferred imaging modality of choice for evaluating osseous and soft tissue masses of the hip by providing information for diagnosis and staging. The MR imaging signal characteristics and enhancement patterns of malignant and benign hip tumors permit specific diagnoses in some cases. Synovial-based tumor-like processes of the hip can be characterized by MR signal characteristics, such as the hemosiderin within PVNS or the cartilage within synovial chondromatosis. Finally, MR imaging can serve to exclude underlying osseous or soft tissue tumors when radiographs display aggressive features of tumor-like processes.

The role of thallium-201 and pentavalent dimercaptosuccinic acid for staging cartilaginous tumours

Introduction

Heterogeneity of cartilage tumours may confound accurate diagnosis and grading resulting in under and over treatment. Improved preoperative assessment of malignancy and grade would be invaluable for developing a rational plan for treatment. We examined correlations between nuclear tracer avidity and malignancy grade in cartilage tumours.

Methods

Between 1996 and 2000, 92 consecutive patients with cartilaginous tumours (50 benign, 42 non-metastatic malignant) underwent nuclear scanning. Thallium-201 (TL-201) and pentavalent dimercaptosuccinic acid (DMSAV) were used as nuclear isotopes. Scanning with these agents was performed on separate days 48 hours apart. Static and SPECT images were obtained at 30 m and 4 h after injection of nuclear tracer. Pathology review was undertaken blinded to the results of the nuclear scans and correlations between histologic results and trace uptake at 4 hours examined.

Results

25 patients with negative DMSAV had benign tumours. 15/17 tumours with positive TL-201 had malignant tumours. 11/13 patients with both positive DMSAV and TL-201 scans had intermediate or high grade tumours and 4 of these developed metastases. We have developed an algorithm for the management of patients with tumours that aims to avoid over treatment of low grade tumours and under treatment of high grade tumours.

Conclusion

Functional nuclear scanning with TL-201 and DMSAV complements other imaging modalities in the management of cartilaginous tumours.

Dedifferentiated chondrosarcoma: use of MRI to guide needle biopsy

AIM

To describe the use of MRI to identify and biopsy areas of dedifferentiation in patients with a suspected diagnosis of dedifferentiated chondrosarcoma.

MATERIALS AND METHODS

Low-grade chondrosarcoma is characterized at magnetic resonance imaging (MRI) as having a lobulate, hyperintense appearance on T2-weighted spin-echo sequences. T2-weighted MR images were assessed in 15 patients with a final pathological diagnosis of dedifferentiated chondrosarcoma for regions of atypical reduced signal intensity. Information regarding the site of ultrasound or computed tomography (CT)-guided biopsy was available in 10 cases.

RESULTS

Nine patients were male and six female with a mean age of 60 years (range 25-77 years). The sites involved were the distal femur (n+4) pelvis (n=3) proximal femur (n=4) femoral diaphysis (n=1) proximal humerus (n=2) and proximal tibia (n=1). The dedifferentiated component consisted of osteosarcoma (n=5) malignant fibrous histiocytoma (n=6) spindle cell sarcoma (n=1) leiomyosarcoma (n=1) and pleomorphic sarcoma (n=1). In 14 of the 15 cases, areas of lower signal intensity lacking in lobulation were identified. In nine of the 10 cases, biopsy site included such areas and yielded high-grade sarcoma.

CONCLUSIONS

Dedifferentiation within chondrosarcoma may be identified on T2-weighted MRI as areas of reduced signal intensity. These areas should be the preferred site of biopsy.

Chest wall tumors: radiologic findings and pathologic correlation: part 2. Malignant tumors

Malignant chest wall tumors are classified into eight main diagnostic categories: muscular, vascular, fibrous and fibrohistiocytic, peripheral nerve, osseous and cartilaginous, adipose, hematologic, and cutaneous. However, there are malignant tumors that arise in the chest wall and that do not fit well in any of these categories (eg, Ewing sarcoma and synovial sarcoma). Malignant chest wall tumors typically manifest as painful, rapidly growing, large palpable masses. Chest radiography, the technique most often used for initial evaluation, can be helpful for detecting cortical destruction. However, computed tomography is more sensitive than chest radiography for detecting calcified tumor matrix and cortical destruction. Magnetic resonance imaging often allows more accurate delineation and localization of the tumor and is helpful for determining the presence and extent of tumor invasion and for tissue characterization. Although the imaging features of many malignant chest wall tumors are nonspecific, knowledge of the typical radiologic manifestations of these tumors often enables their differentiation from benign chest wall tumors and occasionally allows a specific diagnosis to be suggested. The article reviews the clinical and imaging features of the most common malignant chest wall tumors and presents images collected at a single cancer referral center.

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].

From the archives of the AFIP: imaging of primary chondrosarcoma: radiologic-pathologic correlation

Chondrosarcoma is a malignant tumor that produces cartilage matrix, and lesions that arise de novo are called primary. Primary chondrosarcoma is the third most common primary malignant tumor of bone, constituting 20%-27% of all primary malignant osseous neoplasms. There are numerous types of primary chondrosarcomas, including conventional intramedullary, clear cell, juxtacortical, myxoid, mesenchymal, extraskeletal, and dedifferentiated. The conventional intramedullary chondrosarcoma is the most frequent type, and it most commonly involves the long bones or pelvis in up to 65% of cases. Although the pathologic appearance varies with specific lesion type, chondrosarcomas grow with lobular type architecture, and these hyaline cartilage nodules demonstrate high water content and peripheral enchondral ossification. Imaging features directly reflect this pathologic appearance, and the various subtypes often show distinctive features. Radiographic findings often suggest the diagnosis of chondrosarcoma because of identification of typical "ring-and-arc" chondroid matrix mineralization (representing the enchondral ossification) and aggressive features of deep endosteal scalloping and soft-tissue extension. These latter features are usually best assessed, as is lesion staging, with computed tomography (CT) or magnetic resonance (MR) imaging. CT is optimal to detect the matrix mineralization, particularly when it is subtle or when the lesion is located in anatomically complex areas. Both CT and MR imaging depict the high water content of these lesions as low attenuation and very high signal intensity with T2-weighting, respectively. Understanding and recognizing the spectrum of appearances of the various types of primary chondrosarcoma allow improved patient assessment and are vital for optimal clinical management including diagnosis, biopsy, staging, treatment, and prognosis.