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MR of leptomeningeal melanosis in children
S E Byrd1, M Reyes-Mugica, C F Darling
1Department of Radiology, Children's Memorial Hospital, Chicago, Illinois 60614, USA.
Purpose:
To delineate the magnetic resonance (MR) appearance of leptomeningeal melanosis in children.
Method:
Retrospective review of the medical, surgical, pathologic and MR findings in four children with a confirmed histologic diagnosis of leptomeningeal melanosis. The brain MR was performed with T1- and T2-weighted images in all four children and three had T1-weighted post-gadolinium images. Two of the children also had T1-weighted post gadolinium spine images.
Results:
The MR brain findings consisted of cortical plaque and nodular hyperintense lesions on the noncontrast T1-weighted images in one child, marked, diffuse leptomeningeal enhancement in two children, and an enlarged, hypointense left temporal lobe with adjacent mild leptomeningeal enhancement in one child. The MR spine findings consisted of diffuse leptomeningeal enhancement in one child and hyperintensity of the cerebrospinal fluid in the other.
Conclusion:
The T1-weighted pre- and post-contrast images were the best to demonstrate the MR findings in leptomeningeal melanosis which consisted of either diffuse or localized enhancement of the leptomeninges; or cortical plaque and nodular hyperintense lesions pre-contrast.
Insights
Magnetic resonance (MR) imaging reveals key features of leptomeningeal melanosis in children. T1-weighted images, with and without contrast, best show diffuse or localized leptomeningeal enhancement and cortical lesions.
Area of Science:
- Pediatric Radiology
- Neuroimaging
- Oncology
Background:
- Leptomeningeal melanosis is a rare condition involving the spread of melanocytes to the leptomeninges.
- Accurate diagnosis is crucial for appropriate management and prognosis in pediatric patients.
Purpose of the Study:
- To characterize the magnetic resonance (MR) imaging appearance of leptomeningeal melanosis in children.
- To identify specific MR findings indicative of this condition.
Main Methods:
- Retrospective review of medical, surgical, and pathological findings in four pediatric patients with confirmed leptomeningeal melanosis.
- Analysis of brain and spine MR imaging, including T1-weighted, T2-weighted, and post-gadolinium sequences.
Main Results:
- MR findings included cortical plaque and nodular hyperintense lesions (pre-contrast T1-weighted images).
- Diffuse leptomeningeal enhancement was observed in brain and spine imaging.
- One case showed an enlarged, hypointense temporal lobe with mild leptomeningeal enhancement.
Conclusions:
- T1-weighted MR images, both pre- and post-contrast, are optimal for visualizing leptomeningeal melanosis.
- Key findings include diffuse or localized leptomeningeal enhancement and pre-contrast cortical plaque/nodular lesions.