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. 2021 Mar 12;83(Suppl 2):e96-e104.
doi: 10.1055/s-0040-1722717. eCollection 2022 Jun.

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

Aïsha Sooltangos  1 , Istvan Bodi  2 , Prajwal Ghimire  3 , Konstantinos Barkas  3 , Sinan Al-Barazi  3 , Nick Thomas  3 , Eleni C Maratos  3
Affiliations

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

Aïsha Sooltangos et al. J Neurol Surg B Skull Base. .

Abstract

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.

Keywords: BNCTs; EP; benign notochordal cell tumors; chordoma; ecchordosis physaliphora; proton beam radiotherapy.

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Conflict of interest statement

Conflict of Interest None declared.

Figures

Fig. 1
Fig. 1
( A ) CT of the head on admission of Patient 1. Note the enlarged lateral ventricles and the presence of gas in the subarachnoid space. ( B ) MRI of Patient 1 showing the nonenhancing midline clival lesion. ( C ) Clival defect made obvious by fluorescin during the operation. CT, computed tomography; MRI, magnetic resonance imaging.
Fig. 2
Fig. 2
( A ) Preoperative CT of Patient 2 showing clival defect. ( B ) Sagittal MRI showing T2-hyperintense clival lesion. ( C ) T2 axial MRI scan of the clival lesion at presentation. ( D ) T2 axial scan at 8 months postoperatively which shows the mass has been resected. There are stable postoperative appearances. CT, computed tomography; MRI, magnetic resonance imaging.
Fig. 3
Fig. 3
From top left across to bottom right, sequential images of the endoscopic repair of CSF leak in Patient 2. Note the gray gelatinous consistency of the lesion. CSF, cerebrospinal fluid.
Fig. 4
Fig. 4
( A ) CT scan of Patient 4 showing an exophytic lesion at the clivus. ( B ) MRI showing T1-hypointense clival lesion. ( C ) Surgical exploration of clivus. CT, computed tomography; MRI, magnetic resonance imaging.
Fig. 5
Fig. 5
Second operation of Patient 4 to resect presumed chordoma and repair CSF fistula. CSF, cerebrospinal fluid.
See this image and copyright information in PMC

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