- Department of Neurology, University of São Paulo, São Paulo, Brazil
- Department of Anatomic Pathology Division, University of São Paulo, São Paulo, Brazil
Matheus F. de Oliveira
Department of Neurology, University of São Paulo, São Paulo, Brazil
DOI:10.4103/2152-7806.196771Copyright: © 2016 Surgical Neurology International This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License, which allows others to remix, tweak, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
How to cite this article: Arthur J. M. Lopes, Roger S. Brock, Thiago G. Martins, Raphael S. S. de Medeiro, Daniel Montezzo, Matheus F. de Oliveira, Manoel J. Teixeira. Intradural calcifying pseudoneoplasm of the neuraxis presenting as a cauda equina syndrome. 26-Dec-2016;7:
How to cite this URL: Arthur J. M. Lopes, Roger S. Brock, Thiago G. Martins, Raphael S. S. de Medeiro, Daniel Montezzo, Matheus F. de Oliveira, Manoel J. Teixeira. Intradural calcifying pseudoneoplasm of the neuraxis presenting as a cauda equina syndrome. 26-Dec-2016;7:. Available from: http://surgicalneurologyint.com/surgicalint_articles/intradural-calcifying-pseudoneoplasm-of-the-neuraxis-presenting-as-a-cauda-equina-syndrome/
Background:Calcifying nonneoplastic pseudoneoplasms of the neuraxis (CAPNON) have been reported in 59 cases in literature, however, they rarely involve the spinal cord. Owing to the advances in immunohistochemical markers, their structure and origin are better understood now.
Case Report:We present the case of a 72-year-old female who had longstanding history of low back pain that exacerbated 20 days prior to the presentation to the emergency room with a frank cauda equina syndrome. The lumbar computed tomography scan showed a hyperdense lesion, suggestive of calcified tumor, whereas the magnetic resonance imaging revealed a hypointense lesion on theT1 and T2-weighted images, without contrast enhancement or edema on fluid-attenuated inversion recovery. She underwent an emergent L2-L4 laminectomy and L3-L4 discectomy with resection of L2 intradural tumor, following which she regained normal function.
Conclusion:A 72-year-old female presented with a cauda equina syndrome attributed to an L2 intradural CAPNON. Following gross total resection, the patient was neurologically intact.
Keywords: Calcifying nonneoplastic pseudoneoplasms (CAPNON), differential diagnosis, intradural, neoplasm, spine
Calcified pseudoneoplasms of the neuraxis (CAPNON) are nonneoplastic lesions that rarely involve the central nervous system (CNS) and particularly the spine. Clinical features depend on the site of the lesion and may vary from asymptomatic to severely symptomatic; surgical resection is an effective treatment modality.[
Although the clinical presentation is often characterized by pain, with no neurological impairment, neurological deficits may occur if there is significant compression of the neural structures. Here, we describe a 72-year-old female who presented with an acute cauda equina syndrome attributed to CAPNON; following gross total excision, the patient was neurologically intact.
A 72-year-old female, with a longstanding history of low back pain, noted exacerbation of pain 20 days prior to admission with a cauda equina syndrome (2/5 proximal and 0/5 distal strength). A lumbar spine computed tomography (CT) scan showed a hyperdense intravertebral lesion of uncertain etiology (e.g., calcified tumors/ectopic calcifications inside vertebral canal vs. calcified embryological remnants). A lumbar magnetic resonance (MR) revealed with a lesion that was hypointense on T1 and T2-weighted images and showed no enhancement with contrast and no edema on fluid-attenuated inversion recovery studies [Figures
Histological section of calcifying nonneoplastic pseudoneoplasms stained for hematoxilin and eosin (a) and immunohistochemical expression for glial fibrillary acidic protein (GFAP), epithelial membrane antigen (EMA), and smooth muscle actin (b, c, and d, respectively). Optical microscopy, augmented ×200 (blue bar); (a) extensive laminating and concentric arranged calcified lesion with bone formation trabecules associated with fibrous tissue; (b) small and round cell proliferation with minimal atypia surrounding the calcified and fibrous lesion which expressed GFAP; (c) strong and diffuse expression for EMA in the same surrounding cells which denotes ependymal differentiation; (d) fibro-osseous lesion immunostained for smooth muscle actin that demonstrated fibroblastic differentiation
Postoperatively, the patient was discharged on postoperative day 4 with residual proximal 4/5 and distal 2/5 residual motor deficits.
History and etiology of calcifying nonneoplastic pseudoneoplasms
Although common in the limbs, calcifying pseudoneoplasms (CAPNON) are rare lesions in the CNS (brain or spine).[
Clinical presentation and magnetic resonance/computed tomography characteristics
All spinal cord lesions presented with back or cervical pain; only 4 had neurological deficits involving the upper and/or lower extremities.[
Histopathology and immunology
The common histopathologic features of CAPNON include (1) typical chondromyxoid matrix in a nodular pattern; (2) palisading spindle-to-epithelioid cells; (3) variable amounts of fibrous stroma; (4) calcification, osseous metaplasia, and scattered psammoma bodies; and (5) foreign-body reaction with giant cells.[
In general, it stains positive for epithelial membrane antigen (EMA) and vimentin and negative for S100 protein and glial fibrillary acidic protein (GFAP). Smith et al. found positive immunoreactivity to GFAP and S-100 protein in their report of an “unusual fibro-osseous lesion.”[
Surgical management and histopathology and immunological assessment
Gross total resection of this calcified intradural lesion adherent to the cauda equina and filum terminale (size 2.0 × 1.5 × 0.5 cm) was accomplished. Histopathologically, it was calcified (e.g., laminar radiated distribution), accompanied by fibro-osseous metaplastic tissue and a rhyme of small epithelioid cells through the neuropil. Immunohistochemistry demonstrated focal expression of GFAP, S-100 protein, and EMA (“dot” pattern).
With immunohistochemistry, this was a primary CNS lesion composed of glioneuronal cells with probable ependymal origin that differentiated to benign fibro-osseous calcifying tissue. Therefore, the possibility of a neoplastic nature cannot be excluded.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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