Cervical ecchordosis physaliphora: CT and MR features

An Ecchordosis Physaliphora, a Rare Entity, Involving the Central Nervous System: A Systematic Review of the Literature

Ecchordosis physaliphora (EP) is a benign notochordal remnant, which is often an incidental finding; however, it can rarely present with neurological symptoms. We performed a systematic review of the literature for cases of symptomatic EP published in PubMed, Web of Science and Embase from January 1982 to May 2023. This is the largest review to date and revealed 60 cases including ours. Headache (55%) and CSF rhinorrhea (32%) were the most frequent clinical manifestations. The majority of symptomatic EP lesions were located in the prepontine region (77%) and required surgical resection (75%). EP should be considered in patients with neurologic symptoms in the setting of prepontine or posterior sphenoid sinus lesions. While symptomatic patients often require surgical intervention, rare cases may respond to oral corticosteroids.

Do All Notochordal Lesions Require Proton Beam Radiotherapy? A Proposed Reclassification of Ecchordosis Physaliphora as Benign Notochord Cell Tumor

Objectives Ecchordosis physaliphora (EP) is a benign notochord lesion of the clivus arising from the same cell line as chordoma, its malignant counterpart. Although usually asymptomatic, it can cause spontaneous cerebrospinal fluid (CSF) rhinorrhea. Benign notochordal cell tumor (BNCT) is considered another indolent, benign variant of chordoma. Although aggressive forms of chordoma require maximal safe resection followed by proton beam radiotherapy, BNCT and EP can be managed with close imaging surveillance without resection or radiotherapy. However, while BNCT and EP can be distinguished from more aggressive forms of chordoma, differentiating the two is challenging as they are radiologically and histopathologically identical. This case series aims to characterize the clinicopathological features of EP and to propose classifying EP and BNCT together for the purposes of clinical management.

Design Case series.

Setting Tertiary referral center, United Kingdom.

Participants Patients with suspected EP from 2015 to 2019.

Main Outcome Measures Diagnosis of EP.

Results Seven patients with radiological suspicion of EP were identified. Five presented with CSF rhinorrhea and two were asymptomatic. Magnetic resonance imaging features consistently showed T1-hypointense, T2-hyperintense nonenhancing lesions. Diagnosis was made on biopsy for patients requiring repair and radiologically where no surgery was indicated. The histological features of EP included physaliphorous cells of notochordal origin (positive epithelial membrane antigen, S100, CD10, and/or MNF116) without mitotic activity.

Conclusion EP is indistinguishable from BNCT. Both demonstrate markers of notochord cell lines without malignant features. Their management is also identical. We therefore propose grouping EP with BNCT. Close imaging surveillance is required for both as progression to chordoma remains an unquantified risk.

Atypical Presentation and Neuroradiological Features of Giant Ecchordosis Physalyphora in a Seven-Year-Old Patient: A Case Report

This study presented the rare case of a seven-year-old patient with atypical presentation and neuroradiological features of giant ecchordosis physaliphora. The patient underwent cross-sectional imaging due to persistent headache without neurological or visual symptoms. CT scan imaging of the head revealed a hypodense tumor in the prepontine cistern. This lesion caused smooth scalloping of the dorsal clivus without aggressive erosion or calcification, and an osseous stalk was also identified between the lesion and the dorsal wall of the clivus. Sagittal T1 weighted image (T1WI) MRI showed a bilobed, solid and cystic, well-defined lesion, measuring 3.5 cm in terms of craniocaudal diameter, found alongside the midline within the prepontine cistern. After the evaluation of radiological images, the patient was then subjected to endoscopic transnasal complete tumor excision. Histological examination revealed sheets and lobules of clear cells with cytoplasmic globules "physaliphorous cells", and myxoid stroma. There was nuclear pleomorphism associated with focal areas of necrosis. After full recovery and discharge, the patient was followed up for the first year with four-month interval brain MRI scans showing no evidence of residual tumors. On the 12 months follow-up scan, the MRI scan revealed a 1.5 x 0.7 cm recurrent mass in the retroclival right paramidline prepontine cistern, which was most notably seen on the diffusion-weighted images. Series of proton beam therapy with annual MRI scans demonstrated regression of the tumor, eventually allowing the patient to live free of neurological symptoms up to this day. Results suggest that the utilization of radiological imaging such as CT and MRI scans was successful in identifying the ecchordosis physaliphora and differentiating it from chordomas. It can also be inferred that atypical radiological and histopathological findings of ecchordosis physaliphora lesions might suggest that they are prone to recurrence, which is an atypical feature for such entities. Further studies are recommended to explore and better understand these uncommon observations in patients with ecchordosis physaliphora.

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.

Proposed Diagnostic Criteria, Classification Schema, and Review of Literature of Notochord-Derived Ecchordosis Physaliphora

Ecchordosis physaliphora (EP) is a benign notochordal remnant derived from ectopic nests found along the craniospinal axis. It typically presents asymptomatically and is diagnosed using classic radiologic features, particularly location, T1-hypointensity, T2-hyperintensity, and lack of enhancement following gadolinium (Gd) contrast administration. Distinguishing EP from its malignant counterpart, chordoma, is of paramount importance, given the aggressive nature of the latter. Advances in imaging and immunohistochemistry have aided in diagnosis to an extent but, to our knowledge, identification of the genetic fingerprint of EP has yet to take place. Further cytological analysis of these lesions in search of a genetic link is warranted. We propose here a set of diagnostic criteria based on features consistently cited in the literature. In this literature review, 23 case reports were identified and collated into a summary of symptomatic cases of ecchordosis physaliphora. An illustrative case report of two patients was also included. 

[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.

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.

Giant ecchordosis physaliphora in an adolescent girl: case report

The authors describe a rare case of giant ecchordosis physaliphora (EP) in a 16-year-old female patient who presented with diplopia. Magnetic resonance imaging of the brain with Gd contrast revealed a 3.0 × 1.7 × 1.8-cm nonenhancing, extraaxial epidural mass along the dorsal aspect of the clivus that was T2 hyperintense and T1 isointense with intermediate signal on diffusion sequences. Resection via a transnasal transsphenoidal approach to the ventral clival wall resulted in a stable tumor size with no evidence of interval growth after 30 months. Although this case features a strictly extradural EP, this tumor more commonly occurs in the subdural space and requires differentiation from intradural chordoma. Unlike EP, intradural chordoma may enhance with Gd contrast, is more likely to be associated with cranial nerve palsies and brainstem symptoms, and will occasionally have an elevated MIB-1 index. In this paper the authors highlight the different possible midline locations for both EP and chordoma, the difficulty in distinguishing between intradural giant EP and intradural chordoma, and the potential occurrence of these lesions in young people despite their typically slow rate of growth, while also underscoring the need for further investigation into the tumors' cytogenetic behavior.

Paraspinal chordoma mimicking a neurofibroma: a rare but important radiological pitfall

We present an unusual case of a chordoma presenting as an extradural spinal tumour with extension through an expanded intervertebral foramen to form a large paraspinal mass. The magnetic resonance imaging appearances closely mimicked a neurofibroma; however, pre-operative biopsy confirmed the diagnosis of chordoma. This is, to our knowledge, the tenth reported case of chordoma presenting as a mass expanding the intervertebral foramen. Thus, while it is a rare form of chordoma, it can lead to a recognised radiological pitfall. Making the distinction from neurofibroma before surgery is essential, as radical dissection of chordoma is required to reduce the risk of local recurrence.

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.

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.

Clivus chordoma in continuity with a large pontine cyst

Chordomas are tumors commonly of extradural origin associated with bone destruction; their central nervous system invasion has rarely been reported. The authors describe a rare case of a 37-year-old man presenting with a clivial chordoma invading the brainstem with a large pontine cyst. A median suboccipital approach was selected to remove the tumor.

Tumor-biology and current treatment of skull-base chordomas

Chordomas are rare, slow growing tumors of the axial skeleton, which derive from the remnants of the fetal notochord. They can be encountered anywhere along the axial skeleton, most commonly in the sacral area, skull base and less commonly in the spine. Chordomas have a benign histopathology but exhibit malignant clinical behavior with invasive, destructive and metastatic potential. Genetic and molecular pathology studies on oncogenesis of chordomas are very limited and there is little known on mechanisms governing the disease. Chordomas most commonly present with headaches and diplopia and can be readily diagnosed by current neuroradiological methods. There are 3 pathological subtypes of chordomas: classic, chondroid and dedifferentiated chordomas. Differential diagnosis from chondrosarcomas by radiology or pathology may at times be difficult. Skull base chordomas are very challenging to treat. Clinically there are at least two subsets of chordoma patients with distinct behaviors: some with a benign course and another group with an aggressive and rapidly progressive disease. There is no standard treatment for chordomas. Surgical resection and high dose radiation treatment are the mainstays of current treatment. Nevertheless, a significant percentage of skull base chordomas recur despite treatment. The outcome is dictated primarily by the intrinsic biology of the tumor and treatment seems only to have a secondary impact. To date we only have a limited understanding this biology; however better understanding is likely to improve treatment outcome. Hereby we present a review of the current knowledge and experience on the tumor biology, diagnosis and treatment of chordomas.

Sudden death due to subarachnoid bleeding from ecchordosis physaliphora

Ecchordosis physaliphora (EP) is a rare intracranial mass derived from ectopic notochordal tissue. It is usually a fortuitous finding at autopsy or by computed tomography/magnetic resonance imaging. Very few authors have described an EP-associated symptomatology. In this study, we report a case of the sudden and unexpected death of a 48-year-old woman. At autopsy, the cause of death was subarachnoid bleeding, the origin of which was identified as a gelatinous mass stemming from the dura mater and occupying the prepontine space. Further histological and immunohistochemical investigations allowed the diagnosis of EP.

A rare symptomatic presentation of ecchordosis physaliphora: neuroradiological and surgical management

We report a case of ecchordosis physaliphora, an uncommon benign lesion originating from embryonic notochordal remnants, intradurally located in the prepontine cistern, that unusually presented associated with symptoms. MRI detected and precisely located the small mass. At surgery, a cystic gelatinous nodule was found ventral to the pons, contiguous with the dorsal wall of the clivus via a small pedicle. Histological examination diagnosed the lesion as an ecchordosis physaliphora. Here we focus on the analysis of the neuroradiological aspects that play a crucial role from both a diagnostic and a therapeutic standpoint.

Giant vertebral notochordal rest: a lesion distinct from chordoma: discussion of an evolving concept

A 14-year-old boy with severe back pain for several years is described. Roentgenograms, bone scans, and computed tomographic scans of the spine were normal, but magnetic resonance imaging studies showed a lumbar vertebral body lesion, confined to the bone, with low T1- and high T2-weighted signal intensities. Histologically, the lesion consisted of sheet-like notochordal-type tissue, containing physaliphorous cells but lacking the usual features of chordoma. A diagnosis of giant notochordal rest was made. A review of prior possible examples of this recently described and controversial entity is made with a discussion of its embryologic foundations and distinction from chordoma.

Cervical chordoma with vertebral artery encasement mimicking neurofibroma: MRI findings

A case of cervical chordoma in a 36-year-old white man with hypoesthesia in the neck and right shoulder, neck pain, and restricted neck mobility is presented. Plain radiographs of the cervical spine showed radiolucency of the body of C2 on the right side and enlargement of the right intervertebral foramen at C2-C3 level. Tumor encasement of the vertebral artery was demonstrated by MR imaging and confirmed by conventional arteriography. This proved to be particularly important for preoperative assessment.