Clear cell chondrosarcoma: Cytologic findings in six cases

Clear cell chondrosarcoma: a review of clinicopathologic characteristics, differential diagnoses, and patient management

Clear cell chondrosarcoma (CCC), an extremely rare primary bone tumor, is currently classified by the World Health Organization as a low-grade malignant cartilaginous neoplasm. Clinically, CCC occurs primarily in males with a peak incidence in the third to fifth decades of life, and occasionally, it presents in skeletally immature patients. Unlike conventional chondrosarcoma, CCC has a predilection for the epiphysis of long bones and often displays radiologic features reminiscent of chondroblastoma. The recommended treatment is wide operative resection. CCC has a local recurrence rate of approximately 30%, and nearly 20% cases metastasize mainly to bone and lung often a decade after surgical intervention. Incomplete excision or curettage is associated with a high rate of recurrence. Histologically, the process is characterized by infiltrative lobules and sheets of round to oval cells with abundant cleared cytoplasm and well-defined cell borders associated with trabecula of osteoid and woven bone, scattered osteoclasts, and foci of conventional low-grade chondrosarcoma in about one-half of cases. Correlation with clinical and radiologic characteristics, such as epiphyseal location and young patient age, assists in establishing a correct diagnosis. Pathologic diagnosis of CCC is complicated by the low diagnostic accuracy of core needle biopsy, overlapping histologic features with other matrix-rich primary bone tumors, and a lack of a specific immunohistochemical and molecular profile. DNA methylation-based profiling classifier (sarcoma classifier) is one recent technologic advancement that may help to confirm the histopathological diagnosis of CCC or indicate the need for thorough reassessment in cases where results contradict previous conventional findings.

Late Lung Metastasis in a Patient with a Clear Cell Chondrosarcoma: An Indication for a Life-Long Follow-Up?

Background

Clear cell chondrosarcoma (CCCS) is a rare subtype of chondrosarcoma and comprises between 1.6% and 2.5% of all chondrosarcoma. They are known to be chemo- and radiotherapy resistant; surgical resection is therefore the therapy of choice.

Methods

We present a 63-year-old woman with a progressive lung nodule 20 years after initial diagnosis and treatment of a clear cell chondrosarcoma of the right os naviculare.

Results

On serial CT scans of the chest, an asymptomatic, slowly growing nodule in the left upper lung lobe was detected. CT-guided transthoracic biopsy of this nodule confirmed the diagnosis of a chondrosarcoma lung metastasis. Video-assisted thoracoscopic wedge resection was performed with complete removal of the nodule. The patient recovered well from surgery and remains in good health during further follow-up.

Conclusion

Given the tendency of clear cell chondrosarcoma to recur and metastasize after extended periods of time, a long-term, possibly life-long follow-up and clinical surveillance is advisable in these patients.

Clear Cell Chondrosarcoma: Clinical Characteristics and Outcomes in 15 Patients

Background. Clear cell chondrosarcoma (CCC) represents less than 6% of all chondrosarcomas, and thus, our understanding of this rare entity is limited. Analyzing clinical characteristics and treatment patterns, thus increasing our knowledge, may improve treatment strategy. We review our institutional experience with 15 patients, including one case with dedifferentiation. Methods. A retrospective review was conducted in CCC patients treated at our institution from 1996 to 2015, with at least 2-year follow-up. Descriptive statistics and Kaplan–Meier survival analyses were performed. Results. Of 19 patients identified, 15 patients had at least 2-year follow-up and were included. The median age at diagnosis was 43 years. 80% were male. The most common presenting signs were pain (12 patients; 80%) and fracture (2 patients; 13.3%). The most common site was proximal femur (8 patients; 53%). All patients had MSTS Stage I disease. Primary treatment included wide resection in 10 patients (67%) and intralesional or marginal resection in 5 patients (33%). Three patients died of disease during the study period, 1 with dedifferentiation of recurrent CCC. The median time to death from disease was 15.3 years (95% CI: (14.2; NA)). The median time to either recurrence or death was 7.73 years for patients who had intralesional/marginal resection and 16.44 years for patients with wide resection (HR (wide vs. intralesional/marginal) = 0.21, 95% CI: (0.04; 1.18), $p=0.053$ ). The median time to recurrence or death was significantly shorter for patients not initially treated at a sarcoma center ( $p=0.01$ ). Conclusions. CCC is a rare entity, and our understanding of it is still evolving. We observed a higher recurrence rate for intralesional or marginal resection, and wide resection alone remains the mainstay of treatment. Better outcomes were observed in patients initially treated by trained musculoskeletal oncologists. Due to the propensity of CCC to recur decades after initial resection, lifelong surveillance is recommended.

What Factors Are Associated with Treatment Outcomes of Japanese Patients with Clear Cell Chondrosarcoma?

BACKGROUND

Clear cell chondrosarcoma is an extremely rare chondrosarcoma subtype; thus, its treatment outcomes and associated factors have not been widely studied. Knowing more about it is potentially important because clear cell chondrosarcomas are often misdiagnosed as other benign lesions and subsequently treated and followed inappropriately.

QUESTIONS/PURPOSES

(1) What are the patient- and tumor-related characteristics of clear cell chondrosarcoma? (2) What proportion of patients with clear cell chondrosarcoma initially had a misdiagnosis or a misleading initial biopsy result? (3) What is the survivorship of patients with clear cell chondrosarcoma free from death, local recurrence, and distant metastasis, and what factors are associated with greater survivorship or a reduced risk of local recurrence?

METHODS

Between 1985 and 2018, 12 Japanese Musculoskeletal Oncology Group (JMOG) hospitals treated 42 patients with a diagnosis of clear cell chondrosarcoma. All 42 patients had complete medical records at a minimum of 1 year or death, and were included in this multicenter, retrospective, observational study. No patients were lost to follow-up within 5 years of treatment but four were lost to follow-up greater than 5 years after treatment because their physicians thought their follow-up was sufficient. Clinical data were collected by chart review. The median (range) follow-up period was 69 months (2 to 392). In general, when a possibly malignant bone tumor was found on imaging studies, the histological diagnosis was made by biopsy before initiating treatment. Once the diagnosis had been made, the patients were treated by surgery only, complete resection if technically possible, because chondrosarcomas are known to be resistant to chemotherapy and radiotherapy. Unresectable tumors were treated with particle-beam radiation therapy. When patients with chondrosarcoma were referred after unplanned surgical procedures with inadequate surgical margins, immediate additional wide resection was considered before local recurrence developed. This diagnostic and treatment strategy is common to all JMOG hospitals and did not change during the study period. Primary wide resection was performed in 79% (33 of 42) patients, additional wide resection after initial inadequate surgery in 12% (five of 42), curettage and bone grafting in 5% (two of 42) patients, and radiotherapy was administered to 5% (two of 42). Surgical margins among the 40 patients who underwent surgery at JMOG hospitals were no residual tumor in 93% (37 of 42) of patients, microscopic residual tumor in 2% (one of 42), and macroscopic residual tumor or state after curettage or intralesional excision in 5% (two of 42). The oncological endpoints of interest were 5- and 10- year overall survival, disease-free survival, survival free of local recurrence, and survival free of distant metastases; these were calculated using the Kaplan-Meier method and compared using the log-rank test. Risk ratios with their respective 95% confidence intervals (CIs) were estimated in a Cox regression model. The Bonferroni adjustment was used for multiple testing correction.

RESULTS

The sex distribution was 74% men and 26% women (31 and 11 of 42, respectively), with a mean age of 47 ± 17 years. Eighty one percent (34 of 42) of tumors occurred at the ends of long bones, and the proximal femur was the most common site accounting for 60% (25 of 42). The mean size of the primary tumors was 6.3 ± 2.7 cm. Definite pathologic fractures were present in 26% (10 of 42) and another 26% (10 of 42) had extraskeletal involvement. None had metastases at presentation. Twenty four percent (six of 25) tumors in the proximal femur were misdiagnosed as benign lesions and treated inadequately without biopsy. Twenty nine percent (10 of 35) patients had initial misdiagnoses by biopsy and core needle biopsies had a greater risk of resulting in inaccurate histological diagnoses. The study patients' 5- and 10-year overall survival rates were 89% (95% CI 74 to 96) and 89% (95% CI 74 to 96), respectively; 5- and 10- year disease-free survival rates 77% (95% CI 58 to 89) and 57% (95% CI 36 to 75), respectively; 5- and 10-year local recurrence-free survival rates 86% (95% CI 68 to 95) and 71% (95% CI 49 to 86), respectively; and 5- and 10-year distant metastasis-free survival rates 84% (95% CI 67 to 93) and 74% (95% CI 53 to 88), respectively. Notably, bone metastases (17%, seven of 42) were as common as pulmonary metastases (14%, six of 42); four patients developed both bone and pulmonary metastases. The difference between 10-year overall survival rates and 10-year disease-free survival indicated very late recurrence more than 5 years after the initial treatment. After controlling for multiple comparisons, the only factor we found that was associated with local recurrence-free survival was initial treatment (positive margin versus primary wide resection) (risk ratio 8.83 [95% CI 1.47 to 53.1]; p = 0.022 after the Bonferroni adjustment). Additional wide resection reduced the risk of local recurrence.

CONCLUSIONS

The femoral head was the most common location of clear cell chondrosarcoma and had a high risk of misdiagnosis as common benign lesions that resulted in initial inadequate surgery and a consequent high risk of local recurrence. Immediate additional wide resection should be considered in patients who had initial inadequate surgery to reduce the risk of local recurrence. Because clear cell chondrosarcoma can recur locally or distantly in the bones and lungs in the long term, patients should be informed of the risk of very late recurrence and the necessity of decades-long with surveillance for local recurrence and lung and bone metastases.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Clear-cell chondrosarcomas: Fine-needle aspiration cytology, radiological findings, and patient demographics of a rare entity

BACKGROUND

Clear-cell chondrosarcomas (CCCSs) constitute a very rare subtype of chondrosarcoma. CCCS may radiologically mimic chondroblastoma, and given the difference in surgical approach, it is important to distinguish these two entities preoperatively.

DESIGN

Using the institutional digital records, we identified histologically verified CCCS between 1996 and 2013, where preoperative fine-needle aspiration (FNA) cytology was available. Clinical characteristics were categorized and described, and FNAs were reviewed by a panel of senior cytopathologists. In addition, corresponding radiological imaging was reviewed by senior radiologists, and a literature review on CCCS and chondroblastoma was conducted.

RESULTS

A total of seven CCCS FNAs were identified from six patients. The cytomorphology showed low to intermediate cellular smears of clusters and single round or oval tumor cells. Tumor cells had rounded (sometimes binucleated) nuclei with limited pleomorphism and rich vacuolated cytoplasm. Chondroid background matrix was always found. While CCCS patients had a significantly higher age at diagnosis compared to chondroblastoma, no age cut-off would distinctly separate the two.

CONCLUSIONS

CCCS has distinguished cytomorphological features on FNA smears. CCCS should be considered as a possible differential diagnosis in adults (>25 years) with a radiological suspicion of chondroblastoma. Since radiology and patient age cannot conclusively distinguish CCCS from chondroblastoma, FNA may prove an important tool for correct preoperative diagnosis of CCCS.

Prognostic Factors and Treatment Options for Patients with High-Grade Chondrosarcoma

Background

The goal of this study was to determine the prognostic factors exclusive for high-grade chondrosarcoma and whether adjuvant radiotherapy could achieve better overall survival (OS) or cancer-specific survival (CSS) for patients with high-grade chondrosarcoma.

Material/Methods

Surveillance, Epidemiology, and End Results (SEER) cancer registry database was utilized to extract the chondrosarcoma cases diagnosed between 1973 and 2014. Among these cases, the histological grades of poorly differentiated (grade 3) and undifferentiated (grade 4) were categorized as high-grade and included in this study. Chondrosarcoma OS and CSS were the primary outcomes in the present study. The log-rank test was performed for univariate analysis, and the Cox regression model was conducted for multivariate analysis.

Results

A total of 743 patients with high-grade chondrosarcoma were identified in this study (430 cases were poorly differentiated tumors, and 313 cases were undifferentiated tumors). Age at diagnosis, pathological grade, histo-type, SEER stage, tumor size and surgical resection were identified as independent predictors in both OS and CSS analysis of high-grade chondrosarcoma. When stratified by histological grade, surgical resection remained the effective treatment. Strikingly, radiotherapy was determined as an independent protective factor in both OS and CSS analysis of undifferentiated (grade 4) dedifferentiated chondrosarcoma, and adjuvant radiotherapy combined surgical resection could improve both the OS and CSS of patients with undifferentiated myxoid and dedifferentiated chondrosarcoma compared with other treatment regimens.

Conclusions

Our study first demonstrated that adjuvant radiotherapy combined surgery could improve the survival of patients with undifferentiated myxoid and dedifferentiated chondrosarcoma. These results encourage the application of adjuvant radiotherapy for patients with high-grade chondrosarcoma and maximize the patients’ outcome.

Clear cell chondrosarcoma is an underestimated tumor: Report of 7 cases and meta-analysis of the literature

Introduction

Clear cell chondrosarcoma (CCC) is a rare subtype of chondrosarcoma and it is commonly considered a low-grade tumor and less aggressive than atypical cartilaginous tumor (grade 1 central chondrosarcoma). However, the experience even of musculoskeletal tumor centres with this rare entity is limited. The aim of this study is to analyse our own treatment results and those of the literature regarding the therapy and outcome of this lesion.

Material and Methods

7 cases of CCC have been treated in our department between 2003 and 2015. Their follow-up data were collected retrospectively. 187 literature cases with histopathological and clinical characteristics were retrieved by means of a PubMed search with the key word “clear cell chondrosarcoma”. The data pertaining to treatment and follow up were extracted. We analysed the survival of patient and the risk factors for local recurrence (LR) as well as metastatic disease (MD).

Results

The mean age at the time of diagnosis was 40 years. Two thirds of the patients were male. The mean follow-up time was 109 months. To our surprise, there was a high rate of LR (30%) and of MD (20%) when compared to low-grade conventional chondrosarcomas. 15% of LR and 20% of metastatic disease were observed after more than 10 years follow-up. Uncommon locations of MD such as in the spine is a unique observation in chondrosarcomas and underlines the high aggressiveness of this tumor. 10-year overall survival was almost 80%, 10-years disease free survival 60%. Positive margins (p = 0.038) and metastases (p = 0.006) impaired the overall survival significantly. The rate of local recurrence was significantly dependent on resection margin (p < 0.001); however there was no correlation with the grade of differentiation of the tumor. The development of MD was affected by local recurrence (p = 0.006), but we could not detect a significant association with margin status (p = 0.184).

Conclusions

A wide resection is the advocated treatment option. Long term follow-up for at least 10 years is necessary in order to not overlook late LR or MD. This work demonstrates for the first time the apparent aggressiveness of the CCC.

A Case Report of Clear Cell Chondrosarcoma (CCC) Sparing the Epiphysis and Literature Review of CCC

Clear cell chondrosarcoma (CCC) is a rare subtype of chondrosarcoma with a relatively low malignant potential, mainly diagnosed by its characteristic location in the epiphysis of long bones. We report the case of a 33-year-old gentleman who presented with pain, difficulty in walking and restricted range of motion of the right hip joint, with a lesion located in the proximal femoral metaphysis and completely sparing the epiphysis. Needle biopsy was consistent with CCC, which was extremely unusual considering the location of the tumour. The patient was treated by “en bloc” resection of the tumour along with femoral head and reconstruction with hemiarthroplasty. The final histopathology report confirmed the diagnosis with clear surgical margins. The aim of this case report and literature review was to highlight the unusual location of this rare tumour, as such an isolated case of CCC completely sparing the epiphysis has never been reported.

Updates in Primary Bone Tumors: Current Challenges and New Opportunities in Cytopathology

The review summarizes the current diagnostic challenges in fine-needle aspiration of primary bone tumors, with focus on the application of new molecular and immunohistochemical techniques in the diagnosis of giant cell-rich neoplasms, chondrosarcomas, and notochordal tumors.

Clear Cell Chondrosarcoma With Chondroblastoma-Like Features: A Case for Team Diagnosis

Clear cell chondrosarcoma (CCCS) is a rare variant of conventional chondrosarcoma with low-grade malignant features that may be confused radiographically and histologically with chondroblastoma. We report a case of a 50-year-old female who presented with 6 months of left hip pain. Initial radiographs demonstrated an osteolytic lesion with adjacent area of sclerosis in the proximal left femur. Magnetic resonance imaging demonstrated a marrow-infiltrative lesion with periosteal reaction and thickened enhancing periosteum. Biopsy of the sclerotic area demonstrated chondroblastoma-like findings, whereas biopsy of the lytic area showed features suggestive of CCCS. The patient eventually underwent en bloc resection and reconstruction with a proximal femoral megaprosthesis. The final diagnosis was CCCS. We present this unusual case with review of the radiographic and histologic features of CCCS with attention to its ability to mimic chondroblastomas. This case highlights the importance of sampling radiographically heterogeneous areas within a bone lesion to facilitate accurate diagnosis and appropriate management.

Fine needle aspiration biopsy diagnosis of primary clear cell chondrosarcoma: A case report

Clear cell chondrosarcoma is a rare chondrosarcoma variant often involving the long bone epiphyses of young to middle aged adults. We report herein a case involving the left femoral head in a 25-year-old female with a 3-month history of worsening left hip pain. Radiographs revealed a complex, multifocal and lytic lesion centered in the left proximal femoral epiphysis with involvement of the femoral neck. Computed tomography-guided fine needle aspiration biopsy with concomitant core needle biopsy was performed, and a diagnosis of clear cell chondrosarcoma was rendered. Cytologic smears revealed aggregates of matrix material accompanied by a population of mostly uniform spindled to epithelioid and histiocytoid cells, rarely accompanied by osteoclast-type giant cells. The patient underwent surgical resection with -total hip replacement, and subsequent pathologic examination confirmed the initial needle biopsy diagnosis. There has been no evidence of local recurrence or distant metastases with 3-years follow-up. To our knowledge, this is the first reported example of a primary clear cell chondrosarcoma initially evaluated by fine needle aspiration biopsy.

Intraoperative crush smear cytology of vertebral chondroblastoma: A diagnostic challenge

Chondroblastoma is a rare, cartilage producing primary neoplasm of the bone. Although generally benign, chondroblastoma is placed in the "intermediate, rarely metastasizing" category in the 2013 World Health Organization classification of bone tumors. It typically involves the epiphysis of long tubular bones and is exceptionally located in the vertebral column. To the best of our knowledge, less than 35 cases of vertebral chondroblastoma have been reported in the literature. We report a case of chondroblastoma involving D₆ -D₇ vertebrae in a 17-year-old male patient, diagnosed on intraoperative crush cytology and later confirmed on histopathology. Intraoperative crush cytology is rarely been used for the diagnosis of bone lesions. Till date, this is the third case of vertebral chondroblastoma being diagnosed on cytology and first case being diagnosed on intraoperative crush smear cytology. Previous two cases were diagnosed on fine-needle aspiration cytology. Chondroblastoma possesses distinct and diagnostic cytological features, which allows correct diagnosis even in the rarer locations like vertebral column. Crush cytology can be helpful in the rapid intraoperative diagnosis of vertebral chondroblastoma leading to early proper management of the patient.