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Q1: What is the investigation and what does it show?
The investigation is a sagittal T2 weighted magnetic resonance image (MRI) of the dorsal (thoracic) cord. It shows an ovoid, intramedullary (within the spinal cord) lesion with little associated cord expansion. The lesion is of mixed signal intensity and consists of a nodule of high signal abnormality inferiorly with surrounding low signal. The high signal is consistent with subacute blood and represents methaemoglobin, while the low signal is consistent with chronic haemorrhage and represents haemosiderin. There is also high signal abnormality within the spinal cord extending superiorly and inferiorly in keeping with cord oedema. The differential diagnosis for an intramedullary lesion containing blood in various states of degradation is shown in box 1. The appearances are those of a vascular malformation into which haemorrhage has occurred at different times. The lesion is most likely a cavernous malformation because of all vascular malformations these are the most prone to episodes of repeated bleeding. MRI is particularly sensitive at detecting the different blood degradation products formed because of their differing paramagnetic qualities. Although haemorrhage can occur into a tumour, apart from ependymomas, the mixture of subacute and chronic blood would be unlikely. Cord expansion would be expected for a spinal cord tumour and tumours often show contrast enhancement, neither of which were the case for this patient. Although symptoms began while exercising there was no trauma reported and the time course was not correct for traumatic haematomyelia. Previous reports have commented on vascular malformations bleeding after exercise and minor trauma however.
Box 1: Differential diagnosis for intramedullary lesion of the spinal cord of mixed signal intensities
Haemorrhage into a neoplasm
Q2: What should be done next?
The patient has a space occupying lesion of the spinal cord which although probably present for some time, has resulted in recent onset of progressive neurological decline. Immediate neurosurgical assessment with a view to surgical exploration must be arranged if further deterioration is to be prevented.
The patient underwent a two level mid-dorsal laminectomy with complete evacuation of the lesion. At operation abnormal vessels were noted over the surface of the cord but there was no evidence of enlarged feeding vessels or draining veins that would be more in keeping with an arteriovenous malformation (AVM). Histopathological examination showed occasional thin walled blood vessels containing blood clot with surrounding gliosis. There was no evidence of tumour. The lesion was felt to be a cavernous malformation.
Cavernous malformations are uncommon vascular malformations that usually occur intracranially.1 Their presence within the spinal cord, however, is increasingly being recognised with MRI scanning which demonstrates the characteristic but not pathognomonic mixed signal abnormalities of these lesions.2 Clinically they may be asymptomatic but most often present either with progressive or episodic neurological decline, or as in our patient with acute neurological dysfunction.3 Surgery is the treatment of choice for this condition but does not always result in improvement either because total removal of the lesion is not possible or symptoms have been present for weeks to months.4 In cases where symptoms have been present for a short a time as in this patient immediate surgical intervention may halt disease progression and result in clinical improvement.3
Q3: Are any other investigations indicated?
Because of the presence of dilated vessels over the surface of the cord spinal angiography, which is usually normal with cavernous malformations, should be performed to ensure that the lesion is not in fact an AVM. Neither serpentine filling defects nor abnormal “blushes” were seen on angiography in this case excluding an AVM.
Apart from performing a repeat MRI of the spinal cord to determine if the lesion was completely removed, an MRI of the brain should also be performed as some patients have multiple lesions.5 The best management of asymptomatic cerebral lesions is not known.
Q4: What long term problems might this young man have and how should they be managed?
This man presented with the features of incomplete paraplegia with paralysis, anaesthesia, and sphincter disturbance. Postoperatively these did not improve rapidly and he required management in a spinal cord injury rehabilitation programme on both an inpatient and outpatient basis. He is likely to have ongoing problems as outlined in box 2 and require specialist follow up for these and other problems such as pressure sores, neuropathic pain, and management of spasticity.
Box 2: Long term sequelae of intramedullary insult
Impaired activities of daily living skills
Intrinsic spinal cord compression from haemorrhage into a cavernous malformation.
We would like to thank Dr A Gray, Consultant Radiologist, Musgrave Park Hospital, Belfast for making the MR images available and Dr C S McKinstry, Consultant Neuroradiologist, Royal Victoria Hospital, Belfast for reviewing the MR images.