Description

A 4-year-old girl presented to the emergency room with a 2-month history of progressive vomiting and ataxia. Initial workup included a lumbar puncture (LP) that led to rapid neurological decline. Emergent CT of the head revealed a large fourth ventricular tumour and hydrocephalus. Following emergent suboccipital craniotomy and resection, pathology confirmed the diagnosis of atypical teratoid rhabdoid tumour. MRI of the spine obtained on postoperative day 1 was concerning for widespread leptomeningeal disease (figure 1). However, cerebrospinal fluid (CSF) analysis showed no malignant cells with normal cell count, glucose and protein. Upon further review, the subdural spinal enhancement was more likely the result of intracranial hypotension from the initial LP and postsurgical effect as has been reported.1 Follow-up MRI of the spine 3 months later demonstrated resolution of the enhancement seen on the initial MRI of the spine, ruling out leptomeningeal spread (figure 2).

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Figure 1

MRI of the spine at diagnosis revealing extensive enhancement on postgadolinium sequences mimicking leptomeningeal disease (A and D). On T2-weighted sequences (B and E) there is extensive confluent signal also appreciated on T1-weighted sequences (C and F) most consistent with subdural fluid collections related to posterior fossa surgery.

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Figure 2

Postgadolinium sagittal and axial MRI of the spine performed 3 months after the initial surgery revealing no evidence of abnormal enhancement.

The diagnosis of leptomeningeal spread is based on neuroradiological findings in conjunction with CSF analysis. Leptomeningeal disease on MRI shows an enhancement pattern that can be varied from a fine linear signal to thicker coating to the common nodular/studded appearance.2 The finding of subdural enhancement is non-specific and can be attributed to infection, inflammation or intracranial hypotension. Although the frequency of this phenomenon is unknown, the extent of subdural enhancement can vary with all reported cases resolving over time.1 This case demonstrates the difficulty in diagnosing leptomeningeal spread and the importance of making an accurate diagnosis to potentially avoid unnecessary treatment with high-dose craniospinal radiation therapy.