A Spinal Rarity

Rohit SinhaDr Rajendra Prasad

The case of Mr IK

A 35 yr old Bangladeshi stock-broker and M.Phil student presented with a 6/12 Hx of:

Excruciating, constant lower back pain; gradually increasing in severity.

Urinary and faecal constipation.Poor sleep

Previous Pathologies

Diagnosed with Diabetes Mellitus in November 2005

Previously underwent spinal surgery for a what was presumed to be a ependymoma arising from the filum terminale L1- L3.(18/09/1995)

Preoperative MRI from 1995

A T1 weighted saggital MR image of the spine showing a well circumscribed tumour from L1 to L3 with multiple flow voids at the superior pole of the tumour

Other history features

Mr IK takes Gabapentin to relieve his ‘shock like’ neuropathic pain.

Nil relevant Family or Social HxSubjectively, Mr IK is most concerned

about:1.) His anticipation of walking problems2.) His current constipation3.) His disturbed sleep patterns due to

worsening pain

Salient examination findings

Felt unstable on heel-toe walkingNormal joint position senseNormal power, tone, reflexes and co-

ordination (heel-shin drag)Experiences pain on dorsiflexion Has recently noticed that he can no

longer stand on tip toes.

Investigations – MR Spine Imaging

MRI lumbosacral spine report:

‘An elongated, moderately enhancing, lobulated, intradural, altered signal intensity mass lesion is seen from mid L4 to S3 level. Remaining cauda equina nerve roots L1 to L4 level appear thickened, distorted and clumped.’

The T1 post contrast image (right) shows a lobulated tumour extending from L4 – S3, possibly with two components, a lumbral part and a sacral part.

Further imaging investigation

The previous MR images showing multiple flow voids prior to the initial operation are suggestive of a highly vascular tumour

Cystic/highly vascular components are common at the superior pole of such tumours (Aggarwal et al, 1993)

Selective spinal angiography has been recommended by some authors for the assessment of vascularity; even combined with preoperative embolization to minimise intraoperative bleeding (Aghakhani et al, 1999)

Pre-Embolisation image

Post-Embolisation image

The Operative Intervention

A Laminectomy and tumour decompression was carried out at levels L4-S3

Intra-operatively, the tumour was completely confined within the dura

Many nerve roots were incorporated by the tumourThe tumour was soft, friable and highly vascular

despite embolisationThere was no local infiltration by the tumour into

adjacent structuresBiopsy was taken for histopathological analysis

Histopathological biopsy slide 1

‘…Cells have moderate to abundant granular , eosinophilic cytoplasm… mildly pleomorphic nuclei… occasional mitotic figure is seen’

Histopathological biopsy slide 2

‘A layer of spindle shaped Sustentacular cells is seen… cells are positive for synaptophysin … histology is that of a paraganglioma. Note: in view of the presence of foci of necrosis, the tumour may behave aggressively…’

A brief literature review Incidence: Extremely rare. First case reported by Miller & Torrack in 1970, since then only 155

cases have been added to the literature until 2003.Age of patients: Range 12 yrs to 71 yrsSex: No gender preponderanceCommon sites:

90% of paragangliomas occur in the carotid body and glomus jugulare Other CNS sites include the sella turcica, pineal gland, and CP angle.

Spinal paraganglioma are most commonly located at the lumbar spine followed by the cauda equina & filum terminale

Aetiology & Pathophysiology

No concrete aetiology but current research implicates mutations in the SDHD gene and a familial autosomal dominant trait (Masuoka et al, 2001)

Associated with MEN syndrome (Kleiwer & Cochran, 1989)

Unclear whether these are true neoplasia, hyperplasia or hamartomas or even if they actually derive from ectoderm rather than ‘misplaced endoderm’ (Gaffney et al, 1986)

Clinical Features

The main symptom is low back pain (in 90% of cases)

Sciatica accompanies this in 72% of casesMechanical compression is the pathophysiological

factor, but episodes of blood leakage from the tumour are also implicated (Horoupian et al, 1974)

Sensory and motor deficits are found in 35% of cases; 20% show symptom progression

Sphincter dysfunction occurs in 14% of cases and erectile dysfunction has also been reported.

Systemic manifestations are seldom seen.

Diagnosis and Investigations

No particular investigations to document its preoperative diagnosis, but MRI is the investigation of choice (Miliaras et al, 2003)

More common considerations for the differential diagnosis include ependymoma and schwannoma. No Hx or imaging clues to differentiate (systemic amine syndromes are unusual).

MRI features: remarkable, heterogenous enhancement with a vascular/cystic component.

T2 hypointense margins of intradural, well encapsulated tumours attributed to haemosiderin or ferritin from previous haemorrhages (Taira et al, 2000)

Images from the Miliaras et al, 2003

Other investigationsSelective spinal angiography has been

recommended by some authors for the assessment of vascularity; even combined with preoperative embolization to minimise intraoperative bleeding (Aghakhani et al, 1999)

CSF protein levels are elevated as with all lower spinal tumours as noticed by Cushing in 1923.

Intraoperatively, 80% of lesions are encapsulated; only 15% are locally invasive.

Treatment Total excision is the Gold standard for tumours of

such protracted course; since these are usually encapsulated this goal is more realistic.

An important consideration for Mr IK is his previous surgery which may mean the tumour is not completely encapsulated making total excision more difficult/invasiveness more likely.

Such tumours are highly vascular, friable and haemorrhagic. 85% are attached to the filum terminale, or also to nerve rootlets; parts of which may have to be sacrificed with variable postoperative sequelae (Miliaras et al, 2003)

Post operative considerationsAfter SUBtotal removal 12% show regrowth; latest

recorded progression being 30 years postoperatively (Boker et al, 1983)

4 cases are reported in which CSF dissemination has occurred; all had been preceded by an operation.

Postoperative radiotherapy is advocated by some authors for incompletely excised or non-encapsulated tumours; although prevention of tumour recurrence as such has never been demonstrated (Sonneland et al, 1986).

‘Reliable histological criteria to distinguish benign from malignant variant do not exist (Miliaras et al, 2003)

Spinal paragangliomas are classified as grade 1 tumours according to the WHO; less than 1% are aggressive (Moran et al, 1997)

Key References

J Neurooncol.  2003; 65(2):177-90 (ISSN: 0167-594X)Miliaras GC; Kyritsis AP; Polyzoidis KSNeurosurgical Institute, University of Ioannina, Department of Neurosurgery, Medical School, Ioannina, Greece. Aggarwal S, Deck JH, Kucharczyk W: Neuroendocrinetumor (Paraganglioma) of the cauda equina:MRand pathologicfindings. AJNR Am J Neuroradiol 14: 1003–1007,1993

Aghakhani N, George B, Parker F: Paraganglioma of thecauda equina region – Report of two cases and review ofthe literature. Acta Neurochir (Wien) 141: 81–87, 1999

B¨oker DK, Wassmann H, Solymosi L: Paragangliomas ofthe spinal canal. Surg Neurol 19: 461–468, 1983

Gaffney EF, Doorly T, Dinn JJ: Aggressive oncocyticneuroendocrine tumour (‘ocncocytic paraganglioma’) ofthe cauda equina. Histopathology 10: 311–319, 1986