MRI Imaging features of spinal myxopapillary ependymoma

A 32-year-old male patient presented with complaints of severe low-back pain radiating to both legs, mild weakness in both lower limbs since 20 days with delayed deep tendon reflexes on examination. No obvious muscle atrophy. Urinary incontinence was also present since 14 days. No constipation or faecal incontinence, h/o trauma or heavy weight lifting. No fever or other systemic symptoms. CBC, blood and CSF culture were normal.

X-ray of lumbo-sacral spine was done on urgent basis and shows no significant abnormalities. MRI imaging of lumbar spine was performed to evaluate further. MRI with contrast shows well-defined tubular solid long segment intradural lesion within thecal sac extending from inferior endplate of L1 to superior end plate of L3 vertebra. No obvious associated vertebral osseous erosions or posterior paraspinal muscle/neural foraminal extension. It causes almost complete spinal canal stenosis and severe compression/displacement of cauda-equina nerve roots at respected levels. No obvious pre- orparavertebral soft tissue abnormalities at these levels.
Patient was operated with complete excision of this lesion and sent for histopathological analysis. Patient is doing well postoperatively with minimal residual symptoms.

Myxopapillary ependymomas are a variant type of ependymoma that occurs predominantly in the filum terminale and/or conus medullaris. [1] They represent 13% of all spinal ependymomas and are the most common tumours of the cauda-equina region. They are intradural in location. Clinical presentation includes back pain with or without radiation into one or both lower limbs, muscle weakness/absent reflexes or bowel/bladder dysfunction depending upon size and extent of tumour and degree of cauda-equina nerve roots compression. Diagnosis is often delated due to slow growth (over the period of 2 to 3 years) [1].

Types of spinal ependymoma: Cellular ependymoma - classically presents in cervical cord region and myxopapillary ependymoma - seen in lumbo-sacral region. This tumour typically arises from ependymal linings of filum terminale. It can be small or large and cause displacement or compression of adjacent cauda-equina nerve roots causing symptoms. On gross pathological examination, it appears vascular and lobular with or without internal/peripheral haemorrhagic areas. [1]

Imaging modalities including radiography, CT, and MRI help to diagnose and locate the tumour. Radiograph is generally normal except spinal canal widening or vertebral body scalloping if tumour is large. [2] Sacral bony destruction can be seen (rare). CT imaging reveals tumour as lobulated soft tissue density variable sized solid lesion within spinal canal with or without posterior vertebral bodies scalloping or bony destruction. [1] MRI is imaging modality of choice. Tumour appears as well-defined lobulated T1W iso to hypointense and T2W / STIR hyperintense solid lesion within spinal canal with or without neural foraminal extension, osseous infiltration or cauda-equina nerve roots compression. MRI can better show size, extent of lesion with neural foraminal extension / nerve roots compression. [1,2] Few intralesional or peripheral haemorrhagic areas (if present) appear as hypointense on T2W and GRE images (blooming artifacts). Tiny intralesional necrotic or degenerated areas (if present) may appear as hyperintensities on T2W and STIR images. Lesion show homogenous or heterogenous internal contrast enhancement. [1]

Intradural ependymoma rarely metastasise to central nervous system. But extradural ependymoma (although very rare) can metastasise to distant organs such as lungs or bones.

Treatment options include complete surgical resection with or without radiation and chemotherapy. Radiotherapy and chemotherapy is recommended for incomplete surgical excision, recurrence or systemic metastasis. [1] Prognosis is good with 5 year survival rate 98 percent in case of complete surgical excision without systemic metastasis.

Written informed patient consent for publication has been obtained.