Intraosseous Benign Notochord Cell Tumors (BNCT): Further Evidence Supporting a Relationship to Chordoma

Notochordal cell derived lesions: a 55-year casuistic analysis of 50 cases with radiologic-pathologic correlation in a tertiary referral hospital, and literature review

Distinct lesions are derived from notochordal cells (NCDL), ranging from benign to malignant ones. This study presents fifty NCDL cases diagnosed in a tertiary hospital of reference from the past 55 years: forty-two conventional chordomas, including one chondroid chordoma subtype, four benign notochordal cell tumors (BNCT), two conventional chordomas with BNCT foci, and two dedifferentiated chordomas. All patients were adults. Three BNCT were incidentally diagnosed, and one case presented local pain. Chordomas began with local pain and/or neurological symptoms. BNCT were well-defined intraosseous lesions, hypointense on T1-weighted images (WI) and hyperintense on T2-WI, without enhancement in the contrast. Conventional chordomas, including its chondroid subtype, were lobulated masses with cortical disruption and soft tissue extension, hypointense on T1-WI and hyperintense on T2-WI, with variable contrast enhancement. BNCT were histologically composed of solid sheets of vacuolated cells with clear cytoplasm and round and central nuclei. No atypia, lobular growth pattern, myxoid matrix, or bone infiltration were seen. Conventional chordomas were histologically composed of physaliphorous cells in a myxoid stroma with lobulated and infiltrating growth patterns. Observational follow-up using radiological controls was decided on for the BNCT cases. None of these cases presented local recurrence or metastasis. En-bloc resection and adjuvant radiotherapy were selected for sacral and vertebral chordoma cases. Sixteen patients died due to tumor-related factors; twenty-eight presented local recurrence, and four developed distant metastases. New therapeutic options are being studied for chordoma cases. Clinical, radiological, and histopathological data are necessary to properly diagnose and follow up of NCDL.

Chordoma concurrent with benign notochordal cell tumor of the mobile spine. Should the chordoma part be biopsied? - A stepwise approach for management

Some evidence suggests that benign notochordal tumors (BNCTs) could be a potential precursor of chordoma. We present an educational rare case of lumbar vertebral BNCTs concomitant with a destructive lesion not reachable on biopsy but thought to be chordoma. We present a stepwise approach for management of these difficult entities based on radiological features.

Notochordal Tumors

This review provides an overview of the spectrum of tumors showing notochordal differentiation. This spectrum encompasses benign entities that are mostly discovered incidentally on imaging, reported as benign notochordal cell tumor, usually not requiring surgical intervention; slowly growing and histologically low-grade tumors referred to as conventional chordoma but associated with a significant metastatic potential and mortality; and more aggressive disease represented by histologically higher-grade tumors including dedifferentiated chordoma, a high-grade biphasic tumor characterized by a conventional chordoma juxtaposed to a high-grade sarcoma, usually with a spindle or pleomorphic cell morphology, and associated with a poor prognosis and poorly differentiated chordoma.

Primary extradural tumors of the spinal column: A comprehensive treatment guide for the spine surgeon based on the 5th Edition of the World Health Organization bone and soft-tissue tumor classification

BACKGROUND

In 2020, the World Health Organization (WHO) published the 5th version of the soft tissue and bone tumor classification. Based on this novel classification system, we reviewed the current knowledge on all tumor entities with spinal manifestations, their biologic behavior, and most importantly the appropriate treatment options as well as surgical approaches.

METHODS

All tumor entities were extracted from the WHO Soft-Tissue and Bone Tumor Classification (5th Edition). PubMed and Google Scholar were searched for the published cases of spinal tumor manifestations for each entity, and the following characteristics were extracted: Growth pattern, ability to metastasize, peak age, incidence, treatment, type of surgical resection indicated, recurrence rate, risk factors, 5-year survival rate, key molecular or genetic alterations, and possible associated tumor syndromes. Surgical treatment strategies as well as nonsurgical treatment recommendations are presented based on the biologic behavior of each lesion.

RESULTS

Out of 163 primary tumor entities of bone and soft tissue, 92 lesions have been reported along the spinal axis. Of these 92 entities, 54 have the potential to metastasize. The peak age ranges from conatal lesions to 72 years. For each tumor entity, we present recommended surgical treatment strategies based on the ability to locally destruct tissue, to grow, recur after resection, undergo malignant transformation as well as survival rates. In addition, potential systemic treatment recommendations for each tumor entity are outlined.

CONCLUSION

Based on the 5th Edition of the WHO bone and soft tumor classification, we identified 92 out of 163 tumor entities, which potentially can have spinal manifestations. Exact preoperative tissue diagnosis and interdisciplinary case discussions are crucial. Surgical resection is indicated in a significant subset of patients and has to be tailored to the specific biologic behavior of the targeted tumor entity based on the considerations outlined in detail in this article.

Chordoma of the sacrum and mobile spine: a narrative review

Chordoma is a notochord-derived primary tumor of the skull base and vertebral column known to affect 0.08 to 0.5 per 100,000 persons worldwide. Patients commonly present with mechanical, midline pain with or without radicular features secondary to nerve root compression. Management of these lesions has classically revolved around oncologic resection, defined by en bloc resection of the lesion with negative margins as this was found to significantly improve both local control and overall survival. With advancement in radiation modalities, namely the increased availability of focused photon therapy and proton beam radiation, high-dose (>50 Gy) neoadjuvant or adjuvant radiotherapy is also becoming a standard of care. At present chemotherapy does not appear to have a role, but ongoing investigations into the ontogeny and molecular pathophysiology of chordoma promise to identify therapeutic targets that may further alter this paradigm. In this narrative review we describe the epidemiology, histopathology, diagnosis, and treatment of chordoma.

Benign notochordal cell tumor of the clivus with chordoma component: report of 2 cases

Benign notochordal cell tumors (BNCTs) are considered to be benign intraosseous lesions of notochord origin; however, recent spine studies have suggested the possibility that some chordomas arise from BNCTs. Here, the authors describe two cases demonstrating histological features of BNCT and concomitant chordoma involving the clivus, which, to the best of the authors' knowledge, have not been previously documented at this anatomical site.An 18-year-old female presented with an incidentally discovered clival mass. Magnetic resonance imaging revealed a 2.8-cm nonenhancing lesion in the upper clivus that was T2 hyperintense and T1 hypointense. She underwent an uneventful endoscopic transsphenoidal resection. Histologically, the tumor demonstrated areas of classic chordoma and a distinct intraosseous BNCT component. The patient completed adjuvant radiation therapy. Follow-up showed no recurrence at 18 months.A 39-year-old male presented with an incidentally discovered 2.8-cm clival lesion. The nonenhancing mass was T2 hyperintense and T1 hypointense. Surgical removal of the lesion was performed through an endoscopic transsphenoidal approach. Histological analysis revealed areas of BNCT with typical features of chordoma. Follow-up did not demonstrate recurrence at 4 years.These cases document histologically concomitant BNCT and chordoma involving the clivus, suggesting that the BNCT component may be a precursor of chordoma.

Chromosome 3p loss of heterozygosity and reduced expression of H3K36me3 correlate with longer relapse-free survival in sacral conventional chordoma

Conventional chordoma is a rare slow-growing malignant tumor of notochordal origin primarily arising at the base of the skull and sacrococcygeal bones. Chordoma may arise from its benign counterpart, benign notochordal cell tumors, and can also undergo dedifferentiation progressing into dedifferentiated chordoma. No study has directly compared the genomic alterations among these tumors comprising a morphologic continuum. Our prior study identified frequent chromosome 3p loss of heterozygosity and minimal deleted regions on chromosome 3 encompassing SETD2, encoding a histone methyltransferase involved in histone H3 lysine 36 trimethylation (H3K36me3). In the present study, we expanded our study to include 65 sacral conventional chordoma cases, 3 benign notochordal cell tumor cases, and 2 dedifferentiated chordoma cases using single nucleotide polymorphism (SNP) array, targeted next-generation sequencing analysis, and immunohistochemistry. We performed immunohistochemical analysis of histone, H3K36me3, and investigated whether there is any association between the clinical behavior and recurrent chromosome or aneuploidy or H3K36me3 protein expression. We found that there is increased genomic instability from benign notochordal cell tumor to conventional chordoma to dedifferentiated chordoma. The highly recurrent genomic aberration, chromosome 3p loss of heterozygosity (occurred in 70% of conventional chordomas), is correlated with longer relapse-free survival, but not with overall survival or metastasis-free survival in sacral chordoma. Chordomas demonstrate variable patterns and levels of H3K36me3 expression, and reduced expression of H3K36me3 showed marginally significant correlation with longer relapse-free survival. Copy number alterations in the genes encoding the H3K36me3 methylation transferase complex and demethylase may account for the altered H3K36me3 expression levels.

Chordomas: A review with emphasis on their pathophysiology, pathology, molecular biology, and genetics

Chordomas are uncommon, bone, axial, or (rarely) extra-axial tumors that are malignant and frequently recur but less commonly metastasize. They usually affect adults, with a very small proportion being pediatric tumors. For children, such tumors present a different biology, since they are more common as scull rather than sacral tumors, with aggressive histological features, including a loss of SMARCB1/INI1 and a dismal prognosis. Histologically, chordomas, believed to derive from notochordal tissue, characteristically show physaliphorous cells in a myxoid or chondroid matrix. Dedifferentiated and poorly differentiated forms can be observed. Moreover, a grading scale for chordomas has been proposed. Cytokeratin, EMA, S100, and brachyury are expressed by most chordomas. These are chemo-resistant tumors, for which surgical resection and/or radiotherapy are the treatments of choice. In this review, the histological, immunohistochemical, molecular, and clinical data of chordomas are discussed.

Systematic Review of Clinical, Radiologic, and Histologic Features of Benign Notochordal Cell Tumors: Implications for Patient Management

BACKGROUND

There are no absolute defining criteria for benign notochordal cell tumors; the diagnosis is usually based on small size and the absence of aggressive features. Therefore, by definition, the diagnosis is subjective and usually determined by multidisciplinary consensus. A benign notochordal cell tumor should not grow during surveillance, and this may be used to confirm the diagnosis, but is a tautologic definition. Diagnostic ambiguity leads to uncertainty in management. If a tumor is a small chordoma then early surgery is likely to provide a better outcome. However, unnecessary treatment of a benign tumor may incur unjustified risk.

OBJECTIVE

To propose clearer guidelines for the definition and management of benign notochordal tumors.

METHODS

We performed a PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) review of the reported definitions for benign notochordal tumors and their management.

RESULTS

The accepted features of benign notochordal tumors vary considerably: a typical tumor may be diagnosed in the absence of neurology, radiologically well-corticated bony margins, size <35 mm, no enhancement with contrast, no soft tissue extension, no dural penetration, no progression on scans, histologic absence of extracellular myxoid matrix, and low Ki67 index. If these criteria are fulfilled, it is reasonable to use radiologic surveillance in the first instance. Biopsy may be offered depending on the relative risks of performing the biopsy, or if there are atypical features.

CONCLUSIONS

We suggest a clearer definition for a benign notochordal tumor and a management algorithm that incorporates a level of diagnostic uncertainty.

Chordomas: Histopathological Study in View of Anatomical Location

BACKGROUND

Chordomas are aggressive bone tumors that have a predilection for the axial skeleton including the skull base and spinal/sacral bones. However, the histopathological and clinical differences between skull base chordoma (SBC) and sacral/spinal chordoma (SC) are unclear as previous studies have been focused on patient prognosis and treatment outcome. This study aimed to evaluate the clinicopathologic features and prognosis of chordoma according to its location.

METHODS

Patients with chordomas were enrolled, and the histopathologic features were compared according to the tumor location.

RESULTS

A total of 52 patients were enrolled. SBCs had more abundant chondroid matrix and diffuse growth pattern, while SCs had non-chondroid, myxoid matrix and a lobulating pattern, typical of chordoma. Old age and residual tumors were risk factors for shorter overall survival in SBCs. The chondroid matrix was an independent risk factor for shorter disease-free survival in the overall population.

CONCLUSION

Chordomas have different histopathologic features depending on the anatomical location.

Benign notochordal cell tumour: clinicopathology and molecular profiling of 13 cases

Aims

To study the clinicopathological and molecular features of benign notochordal cell tumours (BNCTs) and their differential diagnosis from chordoma.

Methods

13 cases of BNCT were investigated. The genome-wide copy number imbalances were performed using Oncoscan CNV array in three cases and fluorescence in situ hybridisation (FISH) detection of epidermal growth factor receptor (EGFR)/chromosome 7 enumeration probe (CEP7), LSI1p36/1q21, LSI19p13/19q13, CEP3/CEP12 and Telvysion 6 P was performed in 13 cases.

Results

All 13 BNCTs were symptomatic and eight cases showed a close relationship with the bones of the skull base. The important histological character for differential diagnosis with chordoma was the absence of extracellular matrix and eosinophil cells and the presence of vacuoles in most tumour cells. Immunohistochemical staining of AE1/AE3, vimentin, epithelial membrane antigen, S-100 and brachyury (100% each) were positive in BNCTs. Gain of chromosome 7 occurred in 10 cases (76.9%), gain of 1p in four (30.8%), gain of 1q in five (38.5%), gain of 19p and 19q in five (38.5%), gain of chromosome 12 in 11 cases (84.6%), gain of 6p in eight (61.5%) and gain of chromosome 3 in four cases (30.8%).

Conclusions

In contrast to chordoma, chromosome gain or normal copy number was more common while chromosome loss was infrequent in BNCTs. This may be a differential diagnosis clue for chordoma and may be an important characteristic in the progression of notochordal cell tumours.

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.

Computed tomography and magnetic resonance imaging features of cervical chordoma

Computed tomography (CT) and magnetic resonance imaging (MRI) scans of 11 patients with histologically proven cervical chordoma were retrospectively evaluated. Imaging features assessed included location, morphology, association with adjacent structures, vertebral destruction, status of cortical bone, periosteal reaction, attenuation and calcification by CT, and signal intensity and enhancement pattern by MRI. Of 7 cases with CT, 6 exhibited lytic-sclerotic bone destruction. A total of 5 cases exhibited pressure erosion of outer cortex, 3 of which had spiculated periosteal reaction. Calcification was observed in 3 cases. All cases were heterogeneous and hypodense. MRI T2-weighted images (n=10) revealed heterogeneous hyperintense (n=5), intermediate (n=2) and intermediate-hyperintense signal intensity (n=3). Hypointense septa between lobules (n=5) and stripes (n=3) were observed on T2-weighted images. Post-contrast magnetic resonance images (n=6) demonstrated marked heterogeneous (n=3) and ring-like (n=3) enhancement. CT scanning is valuable in revealing the lytic-sclerotic bone destruction, pressure erosion of outer cortex and calcification. MRI is useful in demonstrating the results of soft tissue mass. The two examinations are necessary for differential diagnosis of patients with suspected cervical chordoma.

State-of-the-Art Imaging in Human Chordoma of the Skull Base

Purpose of Review

Chordoma are rare tumours of the axial skeleton which occur most often at the base of the skull and in the sacrum. Although chordoma are generally slow-growing lesions, the recurrence rate is high and the location makes it often difficult to treat. Both computed tomography (CT) and magnetic resonance imaging (MRI) are crucial in the initial diagnosis, treatment planning and post-treatment follow-up.

Recent Findings

Basic MRI and CT characteristics of chordoma were described in the late 1980s and early 1990s. Since then, imaging techniques have evolved with increased resolution and new molecular imaging tools are rapidly evolving. New imaging tools have been developed not only to study anatomy, but also physiologic changes and characterization of tissue and assessment of tumour biology. Recent studies show the uptake of multiple PET tracers in chordoma, which may become an important aspect in the diagnosis, follow-up and personalized therapy.

Summary

This review gives an overview of skull base chordoma histopathology, classic imaging characteristics, radiomics and state-of-the-art imaging techniques that are now emerging in diagnosis, treatment planning and disease monitoring of skull base chordoma.

[Chordoma cutis, an unusual clinical presentation of a rare neoplasm: Chordoma]

Chordoma cutis represents an unusual clinical presentation of a rare neoplasm. The involvement of skin or sub-cutaneous soft tissues can be the consequence of local infiltration or metastasis; the latter may occur several years following the initial diagnosis of chordoma and therefore, may pose a diagnosis challenge when the clinical history of the patient is unknown. The clinical forms, morphology, immuno-histochemical profile and the main differential diagnoses of chordoma cutis are presented here through an anatomoclinical case.

Chordoma arising from benign multifocal notochordal tumors

This case reports a 25-year-old woman initially diagnosed with adjacent benign notochordal cell tumors (BNCTs) of L3 and L4 based on needle biopsy of L3 and stable imaging over a 3-year period who was ultimately found to have a chordoma arising from a BNCT at L3. It illustrates the potential relationship between benign and malignant notochordal tumors and the difficulty in distinguishing them by clinical, radiological, and even histopathological means.

Notochordal Tumors: An Update on Molecular Pathology with Therapeutic Implications

Recent molecular investigations of chordoma show common expression of various receptor tyrosine kinases and activation of downstream signaling pathways contributing to tumor growth and progression. The transcription factor brachyury (also known as T) is important in notochord differentiation, and germline duplication of the gene is often found in familial chordomas. Nuclear expression of brachyury is consistent in chordoma and in benign notochordal cell tumor. Based on the molecular evidence, targeting of several kinds of molecular agents has been attempted for the treatment of uncontrolled chordomas and achieved partial response or stable condition in many cases.

Expression and Therapeutic Potential of SOX9 in Chordoma

Purpose: Conventional chemotherapeutic agents are ineffective in the treatment of chordoma. We investigated the functional roles and therapeutic relevance of the sex-determining region Y (SRY)-box 9 (SOX9) in chordoma.Experimental Design: SOX9 expression was examined by immunohistochemistry (IHC) using 50 chordoma tissue samples. SOX9 expression in chordoma cell lines was examined by Western blot and immunofluorescent assays. We used synthetic human SOX9 siRNA to inhibit the expression of SOX9. Cell proliferation ability and cytotoxicity of inhibiting SOX9 were assessed by 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) and clonogenic assays. The effect of SOX9 knockdown on chordoma cell motility was evaluated by a wound-healing assay and a Transwell invasion chamber assay. Knockdown of SOX9 induced apoptosis, cell-cycle arrest, as well as decreased expression of cancer stem cell markers were determined by Western blot and flow cytometric assays. The effect of the combination of SOX9 siRNA and the chemotherapeutic drug doxorubicin/cisplatin on chordoma cells was assessed by an MTT assay.Results: Tissue microarray and IHC analysis showed that SOX9 is broadly expressed in chordomas and that higher expression levels of SOX9 correlated with a poor prognosis. RNA interference (RNAi)-mediated knockdown of SOX9 inhibited chordoma cell growth, decreased cell motility, and induced apoptosis as well as cell-cycle arrest. Moreover, the combination of SOX9 inhibition and chemotherapeutic drugs had an enhanced anti-cancer effect on chordoma cells.Conclusions: Our results demonstrate that SOX9 plays a crucial role in chordoma. Targeting SOX9 provides a new rationale for treatment of chordoma. Clin Cancer Res; 23(17); 5176-86. ©2017 AACR.

Clinical features and surgical outcomes of patients with skull base chordoma: a retrospective analysis of 238 patients

OBJECTIVE Skull base chordoma is relatively rare, and a limited number of reports have been published regarding its clinical features. Moreover, the factors associated with extent of resection, as well as the value of marginal resection for long-term survival, are still in question for this disease. The objective of this study was to investigate these factors by evaluating their clinical features and surgical outcomes. METHODS A retrospective analysis of 238 patients with skull base chordomas, who met the inclusion criteria, was performed. This study summarized the clinical features, selection of approaches, degree of resection, and postoperative complications by statistical description analyses; proposed modified classifications of tumor location and bone invasion; studied the contributions of the clinical and radiological factors to the extent of resection by Pearson χ², ANOVA, rank test, and binary logistic regression analysis; and estimated the differences in overall survival and progression-free survival rates with respect to therapeutic history, classification of tumor location, extent of bone invasion, and extent of tumor resection by the Kaplan-Meier method. A p value < 0.05 was considered statistically significant. RESULTS The study included 140 male and 98 female patients with a mean age of 38.1 years. Headache and neck pain (33.2%) and diplopia (29%) were the most common initial symptoms. Sphenoclival type accounted for the largest proportion of tumor location (59.2%); endophytic chordoma was the more common type of bone invasion (81.5%). Lateral open approaches were performed in two-thirds of the study population (78.6%). The rate of marginal resection was 66%, composed of gross-total resection (11.8%) and near-total resection (54.2%). Meningitis (8%) and CSF leakage (3.8%) were the most frequent complications. The mean follow-up period was 43.7 months. The overall survival and progression-free survival rates at 5 years were 76% and 45%, respectively. Recurrent tumor and larger tumor volume (≥ 40 cm³) were identified as risk factors of marginal resection. Patients who presented with recurrent tumor and underwent intralesional resection had a worse long-term outcome. CONCLUSIONS The classifications of both tumor location and bone invasion demonstrated clinical value. Marginal resection was more likely to be achieved for primary lesions with smaller volumes (< 40 cm³). The rate of CSF leakage declined due to improved dura mater repair with free fat grafts. Marginal resection, or gross-total resection when possible, should be performed in patients with primary chordomas to achieve better long-term survival.

Metastatic Chordoma: A Diagnostic Challenge on Fine Needle Aspiration

Chordomas are primary low grade malignant tumors of bone that usually arise within both ends of axial skeleton. The Notochord is a midline, ectoderm-derived structure that defines the phylum of chordates. Chordomas may pose difficult diagnostic challenges when encountered in secondary locations, such as lungs or other parenchymatous organs. We report the cytologic findings of a metastatic chordoma sampled through CT-scan guided fine needle aspiration (FNA) of lower lobe lung nodule in a 54-year-old man diagnosed with recurrent chordoma involving the lumber spine and paraspinal region.

[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.

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.

Diagnostic imaging dilemma of a clival lesion and its clinical management implications

Background A retroclival lesion can represent a notochordal remnant-derived mass. The differential diagnoses includes benign lesions such as ecchordosis physaliphora (EP) and neuroenteric cyst or malignant ones such as chordomas. In the case of EP and chordoma, although both types arise from remnants of fetal notochord tissues, they represent two separate entities with different radiographic and biologic behaviors. Case Description We present a case of an incidental finding of a retroclival lesion. The magnetic resonance imaging (MRI) characteristics of the lesion match the neuroimaging profile of a benign lesion and are suggestive of an EP. There was no enhancement noted with the addition of gadolinium. Nonetheless, pathology determined the lesion to be a malignant chordoma. Conclusion The differential diagnosis of a retroclival lesion includes benign and malignant notochordal lesions. Here we present a case of a patient with an incidental finding of a retroclival lesion. Radiographic findings were suggestive of a benign lesion, possibly EP, yet the pathology revealed a chordoma. This report suggests that despite benign imaging, chordoma cannot be excluded and the implications for treatment can be significant. It is important to achieve the correct diagnosis because the prognostic and therapeutic implications are different.

Prognostic value of MIB-1, p53, epidermal growth factor receptor, and INI1 in childhood chordomas

BACKGROUND

Chordomas are slow-growing tumors and most commonly involve the sacrum and clivus. Multiple recurrences are frequent. Childhood chordomas are rare and often show exceptionally aggressive behavior, resulting in short survival and a high incidence of metastatic spread.

OBJECTIVE

This study examined the histologic features and immunohistochemical profile of pediatric chordomas and compared them with their adult counterparts.

METHODS

Nine pediatric and 13 adult cases were included in the study. Childhood chordomas were classified into conventional, atypical, and poorly differentiated types. Immunohistochemistry was performed for cytokeratin, epithelial membrane antigen, vimentin, S100, brachyury, p53, INI1, epidermal growth factor receptor (EGFR), and CD117. Cytogenetic analyses were performed in a subset of tumors for SMARCB1/INI1 locus on 22q chromosome by fluorescent in situ hybridization (FISH) and analysis of the SMARCB1/INI1 gene sequence.

RESULTS

All tumors showed expression of cytokeratin, epithelial membrane antigen, S100, vimentin, brachyury, and EGFR. Atypical morphology, p53 expression, higher MIB-1 labelling index (LI), and INI1 loss were more frequently seen in pediatric chordomas as compared with adults. None of the tumors showed CD117 expression. No point mutation in the SMARCB1/INI1 gene was noted in the tumors examined; however, 4 pediatric and 1 adult chordoma showed loss of this locus on FISH analysis.

CONCLUSIONS

A subset of pediatric chordomas with atypical histomorphologic features needs to be identified, as they behave in an aggressive manner and require adjuvant therapy. Pediatric chordomas more frequently show p53 expression, INI1 loss, and higher MIB-1 LI as compared with adults, whereas EGFR expression is common to both.

Acute cauda equina syndrome secondary to lumbar chordoma: case report and literature review

BACKGROUND CONTEXT

Chordomas are rare tumors in the craniospinal axis arising from persistent notochordal rests commonly seen in the skull base, including the clivus and the sacrum. Chordomas in the mobile spine occur less commonly. To the best of our knowledge, the clinical presentation of acute cauda equina syndrome (CES) due to chordoma of the lumbar vertebra is not published in the English literature.

PURPOSE

To describe an unusual cause of acute CES resulting from chordoma of the lumbar vertebra and discuss management dilemmas in this clinical context.

STUDY DESIGN

Case report with review and discussion.

METHODS

We report the case of a 75-year-old man who presented with acute CES that was clinically considered a metastasis from his previously documented carcinoma of the urinary bladder treated a year ago. Clinical, radiological, and histopathological features of the case and a review of chordomas in the lumbar vertebrae in adults in the published English literature are presented.

RESULTS

He underwent urgent surgical decompression with laminectomy of L3/L4 and L4/L5 with debulking and open biopsy of the tissue mass. Histopathological examination of the tissue mass confirmed the unsuspected diagnosis of chordoma. The salient features of chordomas in the lumbar vertebrae published in the English literature over the last 22 years are summarized. The origin, classification, clinical presentation, and management protocols for lumbar chordomas are also reviewed.

CONCLUSIONS

The clinical presentation of acute CES as the first symptom of chordoma in the lumbar vertebrae is extremely rare. Preoperative tissue diagnosis of this uncommon pathology is usually unavailable. In the face of acute CES, surgical decompression remains the primary goal of management with a planned definitive second-stage curative surgical resection for chordoma.

Coupling of small leucine-rich proteoglycans to hypoxic survival of a progenitor cell-like subpopulation in Rhesus Macaque intervertebral disc

Degeneration of the intervertebral disc (IVD) is a major spinal disorder that associates with neck and back pain. Recent studies of clinical samples and animal models for IVD degeneration have identified cells with multi-potency in the IVD. However, IVD tissue-specific progenitor cells and their niche components are not clear, although degenerated IVD-derived cells possess in vitro characteristics of mesenchymal stromal cell (MSCs). Here, we firstly identified the tissue-specific intervertebral disc progenitor cells (DPCs) from healthy Rhesus monkey and report the niche components modulated the survival of DPCs under hypoxia. DPCs possess clonogenicity, multipotency and retain differentiation potential after extended expansion in vitro and in vivo. In particular, the nucleus pulposus-derived DPCs are sensitive to low oxygen tension and undergo apoptosis under hypoxic conditions due to their inability to induce/stabilize hypoxia-inducible factors (HIF). The presence of small leucine-rich proteoglycans (SLRP), biglycan or decorin, can reduce the susceptibility of DPCs to hypoxia-induced apoptosis via promoting the activation/stabilization of HIF-1α and HIF-2α. As IVD is avascular, we propose SLRPs are niche components of DPCs in IVD homeostasis, providing new insights in progenitor cell biology and niche factors under a hypoxic microenvironment.

Converging paths to progress for skull base chordoma: Review of current therapy and future molecular targets

BACKGROUND

Chordomas of the skull base are rare locally aggressive neoplasms with a predilection for encapsulating critical neurovascular structures, bony destruction and irregular growth patterns, and from which patients succumb to recurrence and treatment failures.

METHODS

A review of the medical literature is performed, using standard search engines and identifying articles related to skull base chordomas, surgery, radiation therapy, chemotherapy, molecular genetics, and prospective trials.

RESULTS

A synthesis of the literature is presented, including sections on pathology, treatment, molecular genetics, challenges, and future directions.

CONCLUSION

Beyond an understanding of the current treatment paradigms for skull base chordomas, the reader gains insight into the collaborative approach applied to orphan diseases, of which chordomas is a prime exemplar.

Benign Notochordal Cell Tumors of the Spine

BACKGROUND:

Notochord-related lesions of the spinal column include benign notochordal cell tumors (BNCTs), ecchordosis physaliphora, both generally considered benign lesions, and chordomas, which represent malignant tumors. The histological similarity of these lesions to the notochord and each other and their strong predilection to the axial skeleton have led to the hypothesis that these lesions represent a continuum of malignant transformation from notochordal remnants, BNCTs, and finally chordomas.

OBJECTIVE:

To present a cohort of biopsy-proven BNCTs with a description of radiographic features, histology, and follow-up to help elucidate the optimal management of these lesions.

METHODS:

A retrospective chart review identified 13 patients with notochordal rest lesions confirmed by histology. Histologic inclusion criteria included notochordal features without evidence of septation, myxoid matrix, nuclear atypia, or mitotic figures. Tumors exhibiting evidence of cortical expansion or destruction were excluded. The natural history and histological and radiographic features were examined.

RESULTS:

Sixteen spinal lesions from 8 patients met the diagnostic criteria for BNCTs, identified on imaging after the patient presented with back pain. Radiographically, all lesions were hypointense on T1-weighted magnetic resonance imaging sequences and hyperintense on T2-weighted and short T1 inversion recovery. The median radiographic follow-up was 21.6 months (range, 8.5-71.2 months). None of the lesions exhibited radiographic or symptomatic progression.

CONCLUSION:

Although limited by short follow-up, our series confirms that these lesions may be safely observed without evidence of malignant transformation, which emphasizes the importance of distinction of BNCT from chordoma at diagnosis and the possibility of close follow-up for these lesions instead of aggressive treatment indicated in patients with chordomas.

Diagnosis and treatment of benign notochordal cell tumors of the spine: report of 3 cases and literature review

STUDY DESIGN

Clinical case series.

OBJECTIVE

To describe the clinical, radiological, and histological presentation of a series of patients presenting with benign notochordal tumors, and review the existing literature on the topic.

SUMMARY OF BACKGROUND DATA

During the past decade, several authors have reported a spine tumor with benign clinical characteristics and histological resemblance to notochordal tissue. The prognosis and appropriate management remain controversial.

METHODS

Description of clinical, radiological, and histological findings in 3 patients with benign notochordal tumors of the spine.

RESULTS

All cases presented with subacute mild pain, without neurological deficit. Tumors developed at L3, S1, and S4, without canal involvement or apparent instability. The first 2 patients presented with classic imagenological findings were treated conservatively, showing no progression on follow-up. The last patient presented an atypical lytic pattern and contrast enhancement on magnetic resonance imaging, and underwent en bloc resection, with significant associated morbidity. Histopathology of the specimen revealed coexistent foci of incipient chordoma.

CONCLUSION

Benign notochordal cell tumors represent a clinical entity derived from notochordal tissue, with characteristics distinct but closely related to the classic chordoma. Some radiological features may suggest the presence of chordoma precursors. Because its true potential for aggressiveness is still undetermined, a careful decision making must weigh the morbidity of en bloc procedures in the spine with uncertain natural history.

Extraskeletal cartilaginous, osseous, and chordoid tumors in children and adolescents

Extraskeletal cartilaginous, osseous, and chordoid tumors are extraordinarily rare in children and adolescents. These lesions are diagnostically challenging due to their rarity and their overlap with metastatic osteosarcoma, reactive or metabolic calcifying and bone-forming masses, various pseudosarcomatous proliferations such as myositis ossificans, and other rare genetic or metabolic disorders. This article reviews the clinicopathologic features and differential diagnosis of extraskeletal cartilaginous, osseous, and chordoid neoplasms in the first two decades of life and highlights the use of diagnostic adjuncts.

Benign notochordal lesions of the axial skeleton: a review and current appraisal

At the 1996 meeting of the International Skeletal Society, an idea was put forth that there existed symptomatic lesions of the axial skeleton, morphologically different from chordoma, that were consistent with benign notochordal remnants (rests). A review of the embryological basis for this concept is made, along with an analysis of these lesions, termed giant notochordal rests or benign notochordal cell tumors, that have been reported in the intervening 15 years, with a commentary on their relationship, if any, to chordoma.

Differentiating benign notochordal cell tumors from chordomas: radiographic features on MRI, CT, and tomography

OBJECTIVE

The purpose of this study was to characterize the imaging spectrum of benign notochordal cell tumors (BNCTs) and chondromas and to determine if this helped in differentiating BNCTs from chordomas.

MATERIALS AND METHODS

Thirty-eight patients pathologically diagnosed with chordomas were reviewed and ultimately diagnosed to have five BNCTs and 33 chordomas. The following radiologic findings were reevaluated by two radiologists by consensus: extraosseous extension, osseous change on CT or conventional tomography, T2-weighted MR signal intensity, T2-weighted signal homogeneity, and contrast-enhanced T1-weighted MR signal intensity. Fisher's exact test was performed to determine statistical significance.

RESULTS

Our study yielded five results. First, four of five BNCTs (80%) were intraosseous, whereas 31 of 33 chordomas (94%) were both intra- and extraosseous (p < 0.0001). Second, all BNCTs showed mild osteosclerosis without bone destruction; all chordomas showed variable osteolysis (p = 0.0092). Third, all BNCTs and 28 of 33 chordomas (85%) showed hyperintensity on T2-weighted images (p > 0.05). Fourth, four of five BNCTs (80%) and 27 of 33 chordomas (82%) were heterogeneous on T2-weighted images (p > 0.05). Fifth, no BNCTs enhanced, whereas all chordomas variably enhanced (p < 0.0001).

CONCLUSION

Radiologic studies may allow distinction of BNCTs from chordomas.

The biological basis for modern treatment of chordoma

Chordomas are rare malignant tumors arising in bone of the spheno-occiput, sacrum, and vertebral column which can cause neurological deficit. Current management of chordoma involves safe resection followed by radiation therapy. However, surgical resection is often subtotal and chordoma often recurs despite optimal therapy. Despite years of effort, effective adjuvant therapy for denovo, recurrent and metastatic chordoma are absent and 5-year survival is at best 65%. While no chemotherapeutic agent has been demonstrated to be effective against chordoma in vivo, a greater understanding of the genetics and molecular biology of chordoma is opening up avenues of investigation towards the rational development of targeted therapies. Although enthusiasm for the use of already established or new investigational agents will increase with greater understanding of chordoma biology, laboratory studies of these agents are important prior to incorporation into clinical human trials. The authors review the current state of knowledge regarding chordoma and offer insight into potential new therapies for this rare and challenging tumor.

Loss of SMARCB1/INI1 expression in poorly differentiated chordomas

Chordomas are malignant neoplasms that typically arise in the axial spine and primarily affect adults. When chordomas arise in pediatric patients they are more likely to display unusual histological features and aggressive behavior. We noted the absence of SMARCB1/INI1 expression by immunohistochemistry in an index case of poorly differentiated chordoma of the sacrum, leading us to further examine SMARCB1/INI1 expression as well as that of brachyury, a highly specific marker of notochordal differentiation, in 3 additional poorly differentiated chordomas of the clivus, 10 typical chordomas, and 8 atypical teratoid/rhabdoid tumors (AT/RTs). All 4 poorly differentiated chordomas and all AT/RTs lacked nuclear expression of SMARCB1/INI1, while the 10 typical chordomas maintained strong nuclear SMARCB1/INI1 immunoreactivity. All 10 typical and 4 poorly differentiated chordomas expressed brachyury; all 8 AT/RTs were brachyury immunonegative. Cytogenetic evaluation utilizing FISH probes near the SMARCB1/INI1 locus on chromosome 22q was also performed in all of the poorly differentiated chordomas in this series. Three of the four poorly differentiated chordomas had evidence for deletion of this region by FISH. Analysis of the SMARCB1/INI1 gene sequence was performed using formalin-fixed paraffin-embedded tissue in all cases and no point mutations were observed. In summary, all poorly differentiated chordomas in this series showed the absence of SMARCB1/INI1 expression, and were reliably distinguished from AT/RTs, clinically by their characteristic primary sites of origin and pathologically by strong nuclear brachyury expression. Our findings reveal a likely role for SMARCB1/INI1 in a subset of chordomas with aggressive features.

Classic chordoma coexisting with benign notochordal cell rest demonstrating different immunohistological expression patterns of brachyury and galectin-3

Increasing numbers of studies support the hypothesis that chordoma arises from notochordal cell rests, although the mechanism awaits further research. Brachyury is the first specific molecule linking chordoma with the notochord, and galectin-3 has been widely used as a marker of notochordal cells. We conducted a histological study of the expression of these two molecules in 46 classic chordoma specimens and unexpectedly found that classic chordoma tumor cells coexisted with benign notochordal cell rests in six specimens. Brachyury and galectin-3 expression were investigated by immunohistochemistry. All specimens contained atypical chordoma tumor cells set within an abundant myxoid matrix, which strongly expressed brachyury and galectin-3. However, brachyury and galectin-3 were not expressed in the notochordal cells. Benign notochordal cells, present as notochord rests, could undergo malignant transformation to form chordoma; however, the cause and role of brachyury and galectin-3 expression in chordoma tumorigenesis requires further careful study.

Lumbar vertebral chordoma arising from an intraosseous benign notochordal cell tumour: radiological findings and histopathological description with a good clinical outcome

Benign notochordal cell tumours have recently been described as intraosseous benign lesions of notochordal cell origin. The lesions are found in vertebral bodies in 20% of autopsy studies and are a potential precursor of chordoma. We report a rare case of lumbar vertebral chordoma that was thought to arise from a benign intraosseous notochordal cell tumour and which showed significant osteosclerotic change. Radiologically, the lumbar vertebral mass lesion showed hyperintensity on T2 weighted images, with scanty enhancement on post-contrast T1 weighted MR images. High uptake corresponding to the mass was noted on fluorine-18-fluorodeoxyglucose positron emission tomography. Bone biopsy revealed proliferation of the physaliphorous cells between thickened bone trabeculae; no nuclear mitosis was observed. Although the mass was diagnosed clinically as spinal chordoma, histopathology contained both benign notochordal cell tumour and conventional chordoma. After heavy particle (11C)-charged radiation therapy was applied to the lesion with a sufficient radiation field margin, the tumour volume significantly decreased and there was improvement in the patient's symptoms. On follow-up radiological studies, the tumour had markedly regressed and there was no tumour regrowth or distant metastasis. In this case report, benign notochordal cell tumour and conventional chordoma are histopathologically identified in the L1 vertebral body, which contains osteosclerotic and osteolytic areas. It is suggested that the benign notochordal cell tumour coexists with a conventional chordoma and that this histopathological finding supports a hypothetical relationship between benign notochordal cell tumour and chordoma.

Intraosseous benign notochordal cell tumor

Intraosseous benign notochordal cell tumor is a presumably benign, intravertebral lesion of notochord origin, which can be found incidentally on removal of the vertebra for unrelated lesions or during an autopsy. The notion of a larger benign notochordal cell tumor that is macroscopic, occasionally symptomatic, and seen radiologically was recently introduced, and described as giant vertebral notochordal rest, giant notochordal hamartoma of intraosseous origin, and benign chordoma . Because of the location, size, and similar histologic and immunohistochemical characteristics, larger benign notochordal cell tumors are easily misdiagnosed as the malignant notochord-type of tumor/chordoma, with critical implications. In this review, we attempt to shed light on the major differences between benign notochordal cell tumors and chordoma and other related notochord lesions, such as notochordal vestiges of the intervertebral disk and ecchordosis physaliphora.

Surgery significantly improves survival in patients with chordoma

STUDY DESIGN

Retrospective database review using Surveillance, Epidemiology, and End Results database, National Cancer Institute.

OBJECTIVE

To determine current treatment outcomes and demographic characteristics and to define the prognostic factors and impact of surgery on survival.

SUMMARY OF THE BACKGROUND DATA

Rarity of the disease has limited the number of population-based studies addressing the issues of prognostic factors and the current treatment outcomes.

METHODS

A total of 962 patients with chordoma, diagnosed between 1973 and 2005, were identified in the Surveillance, Epidemiology, and End Results database. Patient demographics and clinical characteristics, incidence, year of diagnosis, location, size and stage at diagnosis, treatment(s), and survival were extracted. Kaplan-Meier, log-rank, and Cox regression were used to analyze the significance of prognostic factors.

RESULTS

Race specific incidence per 100,000 persons in 2005 shows whites to have the highest (0.473) incidence, followed by Asians/Pacific Islanders (0.091), and Afro-Americans (zero), respectively. The incidence difference between whites and Afro-Americans over time is statistically significant (P < 0.001). The age adjusted incidence reveals a peak in eighth decade of life. Survival was not impacted by race. Age category <59, Hispanic ethnicity, size <8 cm, and surgical resection were all independent predictors of better overall survival. Analysis revealed that survival outcomes were very similar in patients with "in-operable disease" and those in which "surgery was recommended but not performed" suggesting that benefits of resection cannot be solely attributed to selection bias.

CONCLUSION

With high local recurrence rates and the significant functional morbidity associated with surgical resections, clinicians are left wondering if surgery constitutes an appropriate treatment option. Our study clearly demonstrates that surgery significantly improves the overall survival for patients with chordoma. We have further identified age <59 and size of primary tumor <8 cm as important prognostic factors determining the outcome with substantial statistical significance.

Oronasopharyngeal chordomas

BACKGROUND

Chordomas are rare tumors derived from notochordal remnants. The authors report on a series of three cases of primary familial oronasopharyngeal chordomas treated at our institution.

METHODS

A retrospective chart review was completed of the three cases of primary familial oronasopharyngeal chordoma treated at the University of Utah.

FINDINGS

All three patients (100%) were neurologically intact and presented with nasal obstruction. The patients ranged in age from 5 to 65 years and were first-degree relatives. None of the patients had bony erosion of the skull base on imaging, and all of the patients' tumors connected with the skull base via a tract. All three patients were treated with a wide excision combined with drilling of the involved skull base. They all tolerated the procedure without any complications and remain tumor free with a follow-up of 12 months to 4.5 years.

CONCLUSION

Primary oronasopharyngeal chordomas are rare tumors that may present without bony erosion of the skull base. A wide excision with drilling of the involved bony structures may offer an oncologic cure.

Cervical chordoma in childhood without typical vertebral bony destruction: case report and review of the literature

STUDY DESIGN

Case report.

OBJECTIVE

We present a giant cervical chordoma without typical vertebral bony destruction in an 11-year-old girl.

SUMMARY OF BACKGROUND DATA

Chordomas are rare malignant bone tumors that arise at both the cranial and the caudal ends of the axial skeleton, characteristically destroying the bone. Cervical chordomas comprise only 3% to 7% of all chordomas. To our knowledge, there is no case of cervical chordoma in a child, presenting without vertebral body involvement, in English literature.

METHODS

Discussion on the patient's clinical, radiologic history, and histopathologic diagnosis of the resected tumor, with a review of the relevant background literature.

RESULTS

We report the first case of cervical chordoma in a child without typical vertebral bony destruction, the diagnosis of which was difficult to confirm before and after operation.

CONCLUSION

Giant notochordal rest and benign notochordal cell tumors (BNCTs) need to be recognized for differential diagnosis of this atypical chordoma. A long-term follow-up might be necessary for the diagnosis of this nontypical patient.

A rare case of intraosseous benign notochordal cell tumor of the coccyx

This article presents a case of a 53-year-old woman who presented with intermittent, dull, poorly localized lower back and buttock pain. The pain worsened in a seated position or after long periods of standing. A T1-weighted magnetic resonance image (MRI) of the sacrum and coccyx revealed a well-demarcated intraosseous lesion with homogeneous low signal intensity, while T2-weighted MRIs demonstrated homogeneous high signal intensity. An excisional biopsy revealed benign notochord cell tumor. The biopsy proved to be effective, as it relieved the patient's coccydynia. Due to the rarity of intraosseous benign notochordal cell tumors, it is essential to document and review this type of tumor. Only 2 benign notochordal cell tumors involving the coccyx have been previously reported, both of which presented with the same clinical symptoms of chronic coccydynia as our patient, likely due to the location of the involved lesion. The other leading diagnosis in our patient was chordoma, a malignant and locally aggressive neoplasm that is important to consider and exclude. Although chordomas have been well characterized in the surgery, pathology, and radiology literature, the benign notochordal cell tumor is a relative newcomer.