Is the presentation useful in distinguishing between various intradural extramedullary tumours?
Unfortunately no. The majority of patients present with motor deficits as a result of compression of the spinal cord. Less common presentations include sensory deficits, pain and sphincter dysfunction. These symptoms are the same regardless of the cause.
Is the dumbbell shape helpful in narrowing the differential?
Well, usually yes, in so far as it is usually associated with neurogenic tumours (90% schwannomas). Rarely it is seen in spinal meningiomas and other tumours [1-3].
What are the likely diagnoses? Explain.
The differential diagnosis lies between a neurogenic tumour (schwannoma most likely) and a meningioma; although the extension through the exit foramen is more typical of a dumb bell component of a nerve sheath tumour, the relationship to the dura (i.e. dural tail), the thoracic position, and the fact that the patient is a 65 old female, make meningioma the more likely diagnosis.
A tumour mass centred at T9 causes severe cord compression, the cord being displaced to the left side, occupying less than 25% of the cross sectional area of the spinal canal at this level. The tumour mass has two components, that within the dura is slightly hyperintense whereas that external to the dura extending through the T9/10 exit foramen is more hyper intense. Both components demonstrate similar vivid and sharply defined contrast enhancement, demonstrating a connection between the intra and extradural components. The mass extends from the superior border of T9 to the upper border of T10. The cord and spinal canal above and below down are normal.