Imaging features of primary and secondary malignant tumours of the sacrum

Combining morphological and functional imaging parameters to diagnose primary bone neoplasms in the skull base, spine and sacrum

PURPOSE

Morphological magnetic resonance (MR) and computed tomography (CT) features are used in combination with histology for diagnosis and treatment selection of primary bone neoplasms. Isolated functional MRI parameters have shown potential in diagnosis. Our goal is to facilitate diagnosis of primary bone neoplasms of the skull base, mobile spine and sacrum, by a comprehensive approach, combining morphological and functional imaging parameters.

MATERIALS AND METHODS

Pre-treatment MR of 80 patients with histologically proven diagnosis of a primary bone neoplasm of the skull base, mobile spine and sacrum were retrospectively analyzed for morphological and functional MRI parameters. Functional parameters were measured in 4 circular regions of interest per tumor placed on non-adjacent scan slices. Differences in values of functional parameters between different histologies were analyzed with Dunn's test.

RESULTS

Chordomas were the predominant histology (60.0%). Most neoplasms (80.0%) originated in the midline and had geographical (78.2%) bone destruction. Amorphous-type calcification (pre-existing bone) was seen only in chordomas. Homogeneous contrast enhancement pattern was seen only in chondrosarcoma and plasmacytoma. Ktrans and Kep were significantly lower in both chordoma, and chondrosarcoma compared to giant cell tumor of the bone (p = 0.006 - 0.011), and plasmacytoma (p = 0.004 - 0.014). Highest diffusion-weighted MRI apparent diffusion coefficient (ADC) values corresponded to chondrosarcoma and were significantly higher to those of chordoma (p = 0.008).

CONCLUSION

We identified the most discriminating morphological parameters and added functional MR parameters based on histopathological features that are useful in making a confident diagnosis of primary bone neoplasms in the skull base, mobile spine and sacrum.

Characterization of sacral chordoma and differential diagnosis from other sacral malignancy using [18F]FDG PET/CT

2-Deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) positron emission tomography (PET)/computed tomography (CT) is known to be a helpful imaging modality for sacral chordoma, but its detailed characteristics have not been fully described. The purpose of our study was to identify the [18F]FDG PET/CT imaging characteristics of sacral chordoma and compare them with other sacral malignancy. This retrospective study included patients who underwent [18F]FDG PET/CT because of a mass involving the sacrum. Investigated visual findings included visual score and distribution, and semiquantitative parameters measured included standardized uptake values (SUVmax, SUVpeak, SUVmean), tumor-to-liver ratio (TLR), metabolic tumor volume (MTV), total lesion glycolysis (TLG), and tumor size. Comparison studies and receiver operating characteristics (ROC) curve analysis were performed to differentiate between sacral chordoma and other sacral malignancy. Ten patients with sacral chordoma were finally included (M:F = 6:4, median age = 67 yr). On [18F]FDG PET/CT, sacral chordomas presented as a mass with minimal-moderate uptake with a usually heterogenous distribution. Compared with 12 patients with other sacral malignancies (M:F = 4:8, median age 42 yr), sacral chordoma showed a significantly lower TLR (median value 2.1 vs 6.3, P = .021). In ROC curve analysis, TLR showed the largest area under the curve (AUC) of 0.79 (cutoff ≤ 4.0; sensitivity 100.0%, specificity 58.3%; P = .004), and SUVmax showed the second largest AUC of 0.73 (cutoff ≤ 6.9; sensitivity 80.0%, specificity 66.7%; P = .034). [18F]FDG PET/CT of sacral chordoma showed minimal-moderate uptake. The TLR of [18F]FDG PET/CT was significantly lower than that of other sacral malignancy and was the most useful parameter for differentiating sacral chordoma, with the largest AUC. SUVmax could be another helpful semiquantitative parameter.

Role of Apparent Diffusion Coefficient Map-Based First- and High-Order Radiomic Features for the Discrimination of Sacral Chordomas and Chondrosarcomas With Overlapping Conventional Imaging Features

PURPOSE

Chondrosarcomas arise from the lateral pelvis; however, midline chondrosarcomas (10%) display similar imaging features to chordoma, causing a diagnostic challenge. This study aims to determine the diagnostic accuracy of apparent diffusion coefficient (ADC)-based radiomic features and two novel diffusion indices for differentiating sacral chordomas and chondrosarcomas.

METHODS

A retrospective, multireader review was performed of 82 pelvic MRIs (42 chordomas and 40 chondrosarcomas) between December 2014 and September 2021, split into training (n = 69) and validation (n = 13) data sets. Lesions were segmented on a single slice from ADC maps. Eight first-order features (minimum, mean, median, and maximum ADC, standard deviation, skewness, kurtosis, and entropy) and two novel indices: restriction index (RI, proportion of lesions with restricted diffusion) and facilitation index (FI, proportion of lesions with facilitated diffusion) were estimated. One hundred seven radiomic features comparing patients with chondrosarcoma versus chordoma were sorted based on mean group differences.

RESULTS

There was good to excellent interobserver reliability for eight of the 10 ADC metrics on the training data set. Significant differences were observed (P < .005) for RI, FI, median, mean, and skewness using the training data set. Optimal cutpoints for diagnosis of chordoma were RI > 0.015; FI < 0.25; mean ADC < 1.7 × 10-3 mm2/s; and skewness >0.177. The optimal decision tree relied on FI. In a secondary analysis, significant differences (P < .00047) in chondrosarcoma versus chordoma were found in 18 of 107 radiomic features, including six first-order and 12 high-order features.

CONCLUSION

The novel ADC index, FI, in addition to ADC mean, skewness, and 12 high-order radiomic features, could help differentiate sacral chordomas from chondrosarcomas.

Large Intraosseous Haemangioma of the Sacral Vertebra: The radiological imaging findings

NONE

Management of Chordoma of the Sacrum and Mobile Spine

➢

Chordomas account for 1% to 4% of primary tumors of the spine and sacrum.

➢

En bloc resection is the preferred surgical treatment for the management of chordomas.

➢

Proton beam radiation is increasingly being used as a postoperative radiation modality for the treatment of chordomas.

Lumbopelvic shortening and local host bone-to-host bone reconstruction: a surgical method for lumbopelvic fusion following total sacrectomy

PURPOSE

Primary sacral tumors are rare, representing fewer than 7% of spinal neoplasms. Following total sacrectomy, lumbopelvic instrumentation and fusion carries a high risk of non-union with no current consensus on fixation techniques to augment bony defects. We aim to describe the outcome of a reconstruction technique following total sacrectomy whereby lumbopelvic shortening is performed and the posterior pelvic ring is compressed to enable contact with the native L5 vertebra.

METHODS

Retrospective chart review of 2 patients with 2 and 7 years post-operative follow-up. A review of hospital records including clinical assessments, complications, pathology and imaging reports.

RESULTS

Patient 1 was a 17-years-old male with recurrent sacral chondrosarcoma, who presented with lumbosacral neuropathic pain and radiculopathy after failed intralesional surgery. Patient 2 was a 51-years-old male with chronic low back pain caused by a large low-grade chondroid sacral chordoma. Reconstruction technique involved mobilizing the L5 vertebra into the pelvis and pelvic ring closure to obtain host-bone-to-bone contact, eliminating the need for alternative grafts. Post-operative complications included superficial abdominal wound drainage, lower limb DVT, pulmonary emboli and deep pelvic infection. Serial CT scans demonstrated bony fusion in both patients. Neither patients had evidence of tumor recurrence and were able to ambulate at recent follow-up. Imaging demonstrated changed acetabular version of - 4.6/- 8.1 and - 14.4/- 14.8 (patient 1/2, R/L, respectively).

CONCLUSION

Primary lumbopelvic shortening represents an alternative local autograft reconstructive technique for management of large sacral defects following total sacrectomy. This technique obviates the additional morbidity and surgical cost associated with the use of previously described techniques.

The management of sacral tumours

Tumours of the sacrum are difficult to manage. The sacrum provides the structural connection between the torso and lower half of the body and is subject to both axial and rotational forces. Thus, tumours or their treatment can compromise the stability of the spinopelvic junction. Additionally, nerves responsible for lower limb motor groups as well as bowel, bladder, and sexual function traverse or abut the sacrum. Preservation or sacrifice of these nerves in the treatment of sacral tumours has profound implications on the function and quality of life of the patient. This annotation will discuss current treatment protocols for sacral tumours.

Cite this article: Bone Joint J 2022;104-B(12):1284–1291.

Radiographic appearance of a caudal vertebral chordoma in a domestic ferret (Mustela putorius furo)

A 7-year-old spayed female ferret was presented to the Veterinary Teaching Hospital at the Western College of Veterinary Medicine for a slow-growing mass involving the base of the tail. Radiographs revealed a large, irregularly marginated mineralized mass centered on the fifth to seventh caudal vertebrae with osteolysis of the affected caudal vertebrae. A partial caudectomy was performed, and histopathology was consistent with a chordoma. This is the first case report describing the radiographic appearance of a chordoma in the proximal tail and only the second report to describe radiographic findings in a ferret.

Radiomics Models for the Preoperative Prediction of Pelvic and Sacral Tumor Types: A Single-Center Retrospective Study of 795 Cases

Purpose

To assess the performance of random forest (RF)-based radiomics approaches based on 3D computed tomography (CT) and clinical features to predict the types of pelvic and sacral tumors.

Materials and Methods

A total of 795 patients with pathologically confirmed pelvic and sacral tumors were analyzed, including metastatic tumors (n = 181), chordomas (n = 85), giant cell tumors (n =120), chondrosarcoma (n = 127), osteosarcoma (n = 106), neurogenic tumors (n = 95), and Ewing’s sarcoma (n = 81). After semi-automatic segmentation, 1316 hand-crafted radiomics features of each patient were extracted. Four radiomics models (RMs) and four clinical-RMs were built to identify these seven types of tumors. The area under the receiver operating characteristic curve (AUC) and accuracy (ACC) were used to evaluate different models.

Results

In total, 795 patients (432 males, 363 females; mean age of 42.1 ± 17.8 years) were consisted of 215 benign tumors and 580 malignant tumors. The sex, age, history of malignancy and tumor location had significant differences between benign and malignant tumors (P < 0.05). For the two-class models, clinical-RM2 (AUC = 0.928, ACC = 0.877) performed better than clinical-RM1 (AUC = 0.899, ACC = 0.854). For the three-class models, the proposed clinical-RM3 achieved AUCs between 0.923 (for chordoma) and 0.964 (for sarcoma), while the AUCs of the clinical-RM4 ranged from 0.799 (for osteosarcoma) to 0.869 (for chondrosarcoma) in the validation set.

Conclusions

The RF-based clinical-radiomics models provided high discriminatory performance in predicting pelvic and sacral tumor types, which could be used for clinical decision-making.

Multidisciplinary Management of Primary Sacral Tumors: A Tertiary Care Center's Experience and Literature Review

Sacral tumors are rare and can be benign or malignant. Their management is multifactorial and is based on the pathology, extent, and local and distant spread. Managing sacral tumors is challenging due to their proximity to visceral and neural structures. Surgical wide excision has been the standard of care for aggressive benign and malignant tumors. Our purpose was to evaluate the outcomes of a multimodal approach to managing primary sacral tumors in Sakra World Hospital, a tertiary spine care center in Bengaluru, India and perform a literature review to determine a workflow pathway. Our study was a retrospective review of patient records and included 15 patients with primary sacral tumors. Eleven surgically treated patients were evaluated clinically and radiologically and underwent biopsy before surgical excision by an all-posterior approach. A multidisciplinary approach that included intraoperative neural monitoring, plastic reconstruction, adjuvant chemotherapy, and radiotherapy was implemented whenever necessary. Sacral root preservation was attempted whenever feasible. Functional outcomes (based on the Visual Analog Scale [VAS] and Biagini scoring system) were analyzed along with disease control, with a minimum of 2 years of follow-up. The mean follow-up was 29±9.8 months. The mean VAS score significantly improved from 7.8±2.6 to 3.7±3.8 (p=0.026). Bowel function showed statistically significant improvement, from a mean score of 0.81±0.47 to 0.63±0.52 (p=0.026) at 2 years of follow-up. The mean pretreatment motor and bladder function scores were 0.53±0.31 and 0.74±0.44, respectively, improving to 0.48±0.33 and 0.68±0.56 at follow-up but without statistical significance. There was no significant loss of function, which is expected in radical sacral resections. In conclusion, primary sacral tumors require a multidisciplinary approach and management for optimal outcomes. A stand-alone posterior approach can be employed to treat most sacral lesions. En-bloc wide resection is the optimal treatment for primary malignant and aggressive benign tumors. Preservation of at least one functional S2 nerve root is imperative to preserve bowel and bladder function.

Angioleiomyoma of the sacrum: a case report and literature review of similar sacral lesions

Angioleiomyoma is a solitary smooth muscle cell tumor that originates from the tunical media of arteries and veins. Its origin in the sacrum is rare, only one case has been recorded in the literature to date, but cases with bone destruction are even rarer. We present a 49-year-old woman with lumbosacral pain, unsteady gait and right lower extremity pain for two years, accompanied by radiation pain. Through plain film, Computerized tomography (CT) and Magnetic resonance imaging (MRI) examination, we diagnosed this case as giant sacral schwannoma(GSS). After an operation, it was pathologically confirmed as angioleiomyoma. The diagnosis of angioleiomyoma should not be based on imaging alone. It requires histopathological examination combined with immunostaining. It should be considered as one of the differential diagnosis of sacral tumors.

Primary Tumors of the Sacrum: Imaging Findings

The diagnosis of sacral neoplasms is often delayed because they tend to remain clinically silent for a long time. Imaging is useful at all stages of managing sacral bone tumors: from the detection of the neoplasm to the long-term follow-up. Radiographs are recommended as the modality of choice to begin the imaging workup of a patient with known or suspected sacral pathology. More sensitive examinations such as computerized tomography (CT), magnetic resonance (MRI), or scintigraphy are often necessary. The morphological features of the lesions on CT and MRI help to orientate the diagnosis. Although some imaging characteristics are helpful to limit the differential diagnosis, an imaging-guided biopsy is often ultimately required to establish a specific diagnosis. Imaging is of paramount importance even in the long-term follow-up in order to assess any residual tumor when surgical resection is incomplete, to assess the efficacy of adjuvant chemotherapy and radiotherapy, and to detect recurrence.

Primary sacral non-Hodgkin's lymphoma: report of a case and systematic review of literature

INTRODUCTION

Isolated primary sacral diffuse large B cell non-Hodgkin's lymphoma is a very rare entity, and only 11 cases have been reported previously.

CASE PRESENTATION

A 36-year-old man was referred with low backache and radiculopathy pain with a clinico-radiological and cytological diagnosis of sacral metastasis. Histopathological examination and immunohistochemistry of image-guided tissue core biopsy from the sacral mass confirmed it as high-grade diffuse large B cell lymphoma (DLBCL). With normal blood counts and bone marrow, and no lesions elsewhere on imaging, he was staged IAE and received 6 cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone) regimen chemotherapy followed by radiotherapy. The patient has completed a 3-year follow-up and is doing well with yearly imaging showing no evidence of active disease or recurrence.

CONCLUSIONS

The case shows the importance of an image-guided core biopsy and immunohistochemistry over a fine needle aspiration cytology in select cases as it can alter the treatment and outcome in patients. Because of rarity, the treatment and prognosis in primary sacral NHL is not still very clear as it is treated as per the guidelines of treatment of bone lymphoma.

Demystifying Sacral Masses: A Pictorial Review

The sacrum is a triangular shaped bone made up of five fused vertebral bodies. It is composed of bone, cartilage, marrow elements as well as notochord remnants and is a common site for both benign and malignant (primary and secondary) tumors. Familiarity with the imaging features and clinical presentations of sacral bone tumors could be helpful in narrowing the differential diagnosis. Magnetic resonance imaging and computed tomography are the preferred imaging modalities for evaluating sacral masses. This pictorial review will highlight imaging features of common sacral tumors with pathologic correlation. Additionally, this article will review some critical principles and helpful tips to successfully biopsy these lesions.

A Case of Primary Sacral Lymphoma Evaluated by 18F-FDG PET/CT

Primary sacral lymphoma is an unusual bone malignant tumor that poses a diagnostic challenge. Herein, we report a rare case of primary sacral lymphoma, which was initially assessed as suspicious bone metastasis. The subsequent histology and immunohistochemistry of the sacral biopsy confirmed the diagnosis of diffuse large B-cell lymphoma.

Machine and Deep Learning Based Radiomics Models for Preoperative Prediction of Benign and Malignant Sacral Tumors

Purpose

To assess the performance of deep neural network (DNN) and machine learning based radiomics on 3D computed tomography (CT) and clinical characteristics to predict benign or malignant sacral tumors.

Materials and methods

This single-center retrospective analysis included 459 patients with pathologically proven sacral tumors. After semi-automatic segmentation, 1,316 hand-crafted radiomics features of each patient were extracted. All models were built on training set (321 patients) and tested on validation set (138 patients). A DNN model and four machine learning classifiers (logistic regression [LR], random forest [RF], support vector machine [SVM] and k-nearest neighbor [KNN]) based on CT features and clinical characteristics were built, respectively. The area under the receiver operating characteristic curve (AUC) and accuracy (ACC) were used to evaluate different models.

Results

In total, 459 patients (255 males, 204 females; mean age of 42.1 ± 17.8 years, range 4–82 years) were enrolled in this study, including 206 cases of benign tumor and 253 cases of malignant tumor. The sex, age and tumor size had significant differences between the benign tumors and malignant tumors (χ²_sex = 10.854, Z_age = −6.616, Z_size = 2.843, P < 0.05). The radscore, sex, and age were important indicators for differentiating benign and malignant sacral tumors (odds ratio [OR]1 = 2.492, OR2 = 2.236, OR3 = 1.037, P < 0.01). Among the four clinical-radiomics models (RMs), clinical-LR had the best performance in the validation set (AUC = 0.84, ACC = 0.81). The clinical-DNN model also achieved a high performance (an AUC of 0.83 and an ACC of 0.76 in the validation set) in identifying benign and malignant sacral tumors.

Conclusions

Both the clinical-LR and clinical-DNN models would have a high impact on assisting radiologists in their clinical diagnosis of sacral tumors.

Sacral Tumours on MRI: A Pictorial Essay

Tumours of the sacrum can be primary or secondary. Since the sacrum is rich in haematopoietic bone marrow, bone metastases are the most frequent aetiologies. However, tumours can arise from all components of the sacrum and primary bone tumours should be considered in case of a solitary lesion and absence of oncologic history. As the clinical signs are usually non-specific, magnetic resonance imaging has become an indispensable tool in narrowing the differential diagnosis and determining the therapeutic approach. This pictorial essay illustrates specific features of the most common sacral tumours on magnetic resonance (MR) imaging.

Primary neuroendocrine tumor in the presacral region: A case report

BACKGROUND

Primary neuroendocrine tumors (NETs) in the presacral region are extremely rare, some of which are caused by other primary tumors or metastatic rectal carcinoids. Nevertheless, cases of NETs have been increasing in recent years. This report describes the first primary neuroendocrine tumor in the presacral region that was found at our hospital within the last five years.

CASE SUMMARY

The patient was identified as a 36-year-old woman with a presacral mass and pelvic floor pain. A digital rectal examination revealed a presacral mass with unclear margins and obvious tenderness. Magnetic resonance imaging (MRI) demonstrated a 57 mm × 29 mm presacral lump. An ultrasound-guided needle biopsy confirmed a well-differentiated neuroendocrine tumor. No other primary or metastatic tumors were found.

CONCLUSION

Comprehensive consideration of our case report and literature reported by others suggests that a conclusive diagnosis of NETs should be based on computed tomography/MRI and pathological examinations. The treatment of primary NETs in the presacral region mainly relies on surgical procedures with follow-up.

[Management of neurogenic tumors of the sacrum and sacral area]

Tumors of the sacrum rarely occur in routine practice. Due to the absence of pathognomonic symptoms, the diagnosis often becomes apparent at a late disease stage. In this case, the treatment approach depends on the degree of tumor malignancy, growth pattern and location, and relationship between the tumor and the nervous structures, major vessels, and pelvic bones.

OBJECTIVE

Analysis of the overall and relapse-free survival of patients with neurogenic tumors of the sacrum.

MATERIAL AND METHODS

In this study, we analyzed the treatment outcomes in 27 patients with neurogenic sacral tumors who underwent surgery at the Burdenko Neurosurgical Institute.

RESULTS

The median survival time of patients with neurogenic tumors was 72 months; the shortest survival time was observed in a group of neurogenic sarcomas, with the mean survival time being 30 months. Malignant tumors of the peripheral nerves recurred in 100% of cases.

CONCLUSION

Surgical treatment of neurogenic tumors of the sacrum reduces pain, but does not lead to regression of the neurological symptoms caused by compression of the sacral plexus roots. Patients with malignant tumors of the sacrum should undergo partial or complete sacrectomy. In this case, the choice of treatment strategy should be based on assessment of the functional status, tumor histology, and somatic features of the patient.

Comparison of radiomics machine-learning classifiers and feature selection for differentiation of sacral chordoma and sacral giant cell tumour based on 3D computed tomography features

OBJECTIVE

We aimed to identify optimal machine-learning methods for preoperative differentiation of sacral chordoma (SC) and sacral giant cell tumour (SGCT) based on 3D non-enhanced computed tomography (CT) and CT-enhanced (CTE) features.

METHODS

A total of 95 patients were divided into a training set and a validation set. Three best feature selection methods (Relief, least absolute shrinkage and selection operator (LASSO) and Random Forest (RF)) and three classification methods, including generalised linear models (GLM), support vector machines (SVM) and RF, were compared for their performance in distinguishing SC and SGCT. The performance of the radiomics model was investigated via area under the receiver-operating characteristic curve (AUC) and accuracy (ACC) analysis.

RESULTS

The selection method LASSO + classifier GLM had the highest AUC of 0.984 and ACC of 0.897 in the validating set, followed by Relief + GLM (AUC = 0.909, ACC = 0.862) and LASSO + SVM (AUC = 0.900, ACC = 0.862) based on CTE features. For CT features, RF + GLM had the highest AUC of 0.889, while LASSO + GLM achieved a high ACC of 0.793 in the validating set. Regardless of the methods, CTE features significantly outperformed those from CT for the differentiation of SC and SGCT (Z_AUC = -3.029, Z_ACC = -4.553; p < 0.05).

CONCLUSIONS

Our study demonstrated CTE features performed better than CT features. The selection method LASSO + classifier GLM had the best performance in differentiation of SC and SGCT, which could enhance the application of radiomics methods in sacral tumours.

KEY POINTS

• Sacral chordoma and sacral giant cell tumour are the two most common primary tumours of the sacrum with many common clinical and imaging characteristics. • A radiomics model helps clinicians to identify the histology of a sacral tumour. • CTE features should be preferred.

Humeral metastasis of sacrococcygeal chordoma detected by fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography: A case report

Chordomas are rare, slow-growing, locally aggressive bone tumors arising from embryonic remnants of the notochord. Distant metastases most commonly involve the lung, liver, axial skeleton, skin, and lymph nodes. Humeral metastases are extremely rare. We report the case of a recurrent chordoma with humeral metastasis, complicated with pathologic fracture. Fluorine-18 fluorodeoxyglucose positron emission tomography-computed tomography revealed multiple hypermetabolic skeletal lesions, corresponding to the symptoms. Our report suggests that positron emission tomography-computed tomography is useful for evaluation of recurrence and distant metastases of chordomas.

Pictorial review of 18F-FDG PET/CT findings in musculoskeletal lesions

We herein reviewed ¹⁸F-fluoro-2-deoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) findings in a number of musculoskeletal lesions including malignant tumors, benign tumors, and tumor-like lesions with correlations to other radiographic imaging modalities, and described the diversity of the ¹⁸F-FDG PET/CT findings of this entity. Malignant primary musculoskeletal tumors are typically ¹⁸F-FDG avid, whereas low-grade malignant tumors show mild uptake. Benign musculoskeletal tumors generally show a faint uptake of ¹⁸F-FDG, and tumor-like conditions also display various uptake patterns of ¹⁸F-FDG. Although musculoskeletal tumors show various uptakes of ¹⁸F-FDG on PET/CT, its addition to morphological imaging modalities such as CT and MRI is useful for the characterization and differentiation of musculoskeletal lesions.

[Chordoma]

PURPOSES

To review in the literature, all the epidemiological, clinical, radiological, histological and therapeutic data regarding chordomas as well as various notochordal entities: ecchordosis physaliphora, intradural and intraparenchymatous chordomas, benign notochordal cell tumors, parachordomas and extra-axial chordomas. To identify different types of chordomas, including familial forms, associations with tuberous sclerosis, Ollier's disease and Maffucci's syndrome, forms with metastasis and seeding. To assess the recent data regarding molecular biology and progress in targeted therapy. To compare the different types of radiotherapy, especially protontherapy and their therapeutic effects. To review the largest series of chordomas in their different localizations (skull base, sacrum and mobile spine) from the literature.

MATERIALS

The series of 136 chordomas treated and followed up over 20 years (1972-2012) in the department of neurosurgery at Lariboisière hospital is reviewed. It includes: 58 chordomas of the skull base, 47 of the craniocervical junction, 23 of the cervical spine and 8 from the lombosacral region. Similarly, 31 chordomas in children (less than 18 years of age), observed in the departments of neurosurgery of les Enfants-Malades and Lariboisière hospitals, are presented. They were observed between 1976 and 2010 and were located intracranially (n=22 including 13 with cervical extension), 4 at the craniocervical junction level and 5 in the cervical spine.

METHODS

In the entire Lariboisière series and in the different groups of localization, different parameters were analyzed: the delay of diagnosis, of follow-up, of occurrence of metastasis, recurrence and death, the number of primary patients and patients referred to us after progression or recurrence and the number of deaths, recurrences and metastases. The influence of the quality of resection (total, subtotal and partial) on the prognosis is also presented. Kaplan-Meier actuarial curves of overall survival and disease free survival were performed in the entire series, including the different groups of localization based on the following 4 parameters: age, primary and secondary patients, quality of resection and protontherapy. In the pediatric series, a similar analysis was carried-out but was limited by the small number of patients in the subgroups.

RESULTS

In the Lariboisière series, the mean delay of diagnosis is 10 months and the mean follow-up is 80 months in each group. The delay before recurrence, metastasis and death is always better for the skull base chordomas and worse for those of the craniocervical junction, which have similar results to those of the cervical spine. Similar figures were observed as regards the number of deaths, metastases and recurrences. Quality of resection is the major factor of prognosis with 20.5 % of deaths and 28 % of recurrences after total resection as compared to 52.5 % and 47.5 % after subtotal resection. This is still more obvious in the group of skull base chordomas. Adding protontherapy to a total resection can still improve the results but there is no change after subtotal resection. The actuarial curve of overall survival shows a clear cut in the slope with some chordomas having a fast evolution towards recurrence and death in less than 4 years and others having a long survival of sometimes more than 20 years. Also, age has no influence on the prognosis. In primary patients, disease free survival is better than in secondary patients but not in overall survival. Protontherapy only improves the overall survival in the entire series and in the skull base group. Total resection improves both the overall and disease free survival in each group. Finally, the adjunct of protontherapy after total resection is clearly demonstrated. In the pediatric series, the median follow-up is 5.7 years. Overall survival and disease free survival are respectively 63 % and 54.3 %. Factors of prognosis are the histological type (atypical forms), localization (worse for the cervical spine and better for the clivus) and again it will depend on the quality of resection.

CONCLUSIONS

Many different pathologies derived from the notochord can be observed: some are remnants, some may be precursors of chordomas and some have similar features but are probably not genuine chordomas. To-day, immuno-histological studies should permit to differentiate them from real chordomas. Improving knowledge of molecular biology raises hopes for complementary treatments but to date the quality of surgical resection is still the main factor of prognosis. Complementary protontherapy seems useful, especially in skull base chordomas, which have better overall results than those of the craniocervical junction and of the cervical spine. However, we are still lacking an intrinsic marker of evolution to differentiate the slow growing chordomas with an indolent evolution from aggressive types leading rapidly to recurrence and death on which more aggressive treatments should be applied.

Surgical treatment of primary malignant tumors of the sacrum

OBJECTIVES

The objective of the authors was to provide an up-to-date review about the epidemiology, diagnosis, and surgical management of the malignant primary sacral tumors.

METHODS

A PubMed search was conducted using a combination of the following items: (('Spinal Neoplasms'[Mesh]) AND 'Sacrum'[Mesh]) NOT ('Metastasis' OR 'Metastases' OR 'Benign'). The literature review and the author's own surgical experiences were used to assess the current treatment strategies of the malignant sacral tumors.

RESULTS

Twenty case series were identified, which studies discuss in detail the surgical strategies, the postoperative complications, the functional and oncologic outcome, and the recurrence-free and disease-specific survival of this rare patient category.

DISCUSSION

Sacral tumors are rare pathologies. Their management generates a complex medical problem, as they usually are diagnosed in advanced stages with extended dimensions involving the sacral nerves and surrounding organs. The evaluation and complex treatment of these rare tumors require a multidisciplinary approach, optimally at institutions with comprehensive care and experience. Although conventional oncologic therapeutic methods should be used as neoadjuvant or adjuvant therapies in certain histological types, en bloc resection with wide surgical margins is essential for long-term local oncologic control. This is often technically difficult to achieve, as just a few centers in the world perform sacral tumor surgeries on a regular basis, and have enough wide experience. Therefore international cooperation and organization of multicenter tumor registries are essential to develop evidence based treatment protocols.

Difficulty distinguishing benign notochordal cell tumor from chordoma further suggests a link between them

Background

Much discussion about benign notochordal cell tissue in vertebrae has centered on the nature of its relationship, if any, to chordoma. Often referred to as benign notochordal cell tumors (BNCTs), these lesions have unique morphological features, however, differentiating between notochordal cells in discs, BNCT, and chordoma can be difficult. They are described as radiologically distinct from chordoma, with lysis, contrast enhancement, and a soft tissue mass indicating chordoma.

Methods

All chordomas diagnosed at our institution, the Istituto Ortopedico Rizzoli (Bologna, Italy), prior to 2008 were reviewed, yielding 174 cases. Five were limited to bone; one was a recurrent chordoma without original data available. The remaining four were re-evaluated in detail.

Results

There were three women and one man, aged 33–57 years (mean, 48 years). Two were BNCTs and two were mixed lesions containing BNCT and chordoma. On computed tomography, all were radiopaque with areas of lysis. One BNCT was heterogeneous on magnetic resonance imaging, enhancing after contrast. Microscopically, one BNCT had a well-defined cystic area with a sclerotic border. The other had a minute atypical area; it recurred as chordoma. The mixed lesions had areas of definitive BNCT, definitive chordoma, and atypical areas that did not meet the criteria for either. The atypical areas in all three cases ‘blended’ with areas of chordoma or BNCT.

Conclusion

These cases illustrate the ongoing challenges in differentiating between BNCT and chordoma. All had unique imaging features; three had atypical microscopic areas blending with BNCT or chordoma, strengthening the argument for a relationship between the two entities and supporting the idea that some BNCTs may progress to chordoma. Our study dispels the notion that any single radiologic criterion used to distinguish between chordoma and BNCT is reliable, opening the discussion as to whether or how to monitor BNCTs.

Surgical Management of Primary and Metastatic Spinal Tumors

Background

The axial skeleton is a common site for primary tumors and metastatic disease, with metastatic disease being much more common. Primary and metastatic spinal tumors have a diverse range of aggressiveness, ranging from benign lesions to highly infiltrative malignant tumors.

Methods

The authors reviewed the results of articles describing the treatment and outcomes of patients with metastatic disease or primary tumors of the spinal column.

Results

En bloc resection is the mainstay of treatment for malignant primary tumors of the spinal column. Intralesional resection is generally appropriate for benign primary tumors. Low-quality evidence supports the use of chemotherapy in select primary tumors; however, radiation therapy is often used for incompletely resected or unresectable lesions. Surgical considerations for the treatment of metastatic disease are more nuanced and require that the health care professional consider patient performance status and the pathology of the primary tumor.

Conclusions

The treatment of metastatic and primary tumors of the spinal column requires a multidisciplinary approach in order to offer patients the best opportunity for long-term survival.

High fluorodeoxyglucose ((18)F)PET-uptake lymph nodes in a patient with chordoma: Tumor metastasis or sarcoidosis?

Patient: Male, 48

Final Diagnosis: Chordoma

Symptoms: —

Medication: —

Clinical Procedure: —

Specialty: Neurology

Differentiation of primary chordoma, giant cell tumor and schwannoma of the sacrum by CT and MRI

OBJECTIVE

To evaluate criteria to differentiate sacral chordoma (SC), sacral giant cell tumor (SGCT) and giant sacral schwannoma (GSS) with CT and MRI.

MATERIALS AND METHODS

CT and MR images of 22 SCs, 19 SGCTs and 8 GSSs were reviewed. The clinical and imaging features of each tumor were analyzed.

RESULTS

The mean ages of SC, SGCT and GSS were 55.1 ± 10.7, 34.3 ± 10.7 and 42.4 ± 15.7 years old. SCs (77.3%) were predominantly located in the midline of lower sacrum, while most SGCTs (73.7%) and GSSs (87.5%) were eccentrically located in upper sacrum. There were significant differences in age, location, eccentricity, morphology of bone residues, intratumoral bleeding and septations. Multiple small cysts were mainly observed in SGCTs (73.7%) with large central cysts in GSSs (87.5%). SGCTs expanded mainly inside sacrum while SCs and GSSs often extended into pelvic cavity (P = 0.0022). Involvement of sacroiliac joints and muscles were also different. Ascending extension within sacral canal was only displayed in SCs. The preservation of intervertebral discs showed difference between large and small tumors (P = 0.0002), regardless of tumor type (P = 0.095). No significant difference was displayed in gender (P = 0.234) or tumor size (P = 0.0832) among three groups.

CONCLUSION

Age, epicenter of the lesion (midline vs. eccentric and upper vs. lower sacral vertebra), bone residues, cysts, bleeding, septation, expanding pattern, muscles and sacroiliac joint involvement can be criteria for diagnosis. Fluid-fluid level is specific for SGCTs and ascending extension within the sacral canal for SCs. The preservation of intervertebral discs is related to tumor size rather than tumor type.