PMC4209706_01
Brain MRI (a-c) showing diffuse areas of FLAIR signal changes (a) and T1W post-gadolinium sequence with diffuse leptomeningeal and nodular parenchymal enhancement (b, arrow) and cranial nerve enhancement (c, arrow showing CNIII). Post-contrast scan of cervical (d) and thoracic (e) spine showing diffuse nodular leptomeningeal enhancement. This was most significant at the lower lumbar region with almost complete obliteration of normal CSF signal on T2WI (f)
SNI-5-147-g001.jpg
PMC4209706_01_SNI-5-147-g001.jpg
F1
Brain magnetic resonance imaging (MRI) showed extensive leptomeningeal enhancement with a small focus of nodular parenchymal enhancement [Figure 1a and b], and non-specific T2 white matter hypointensities [Figure 1c]. Brain MRI was unchanged while spine MRI showed diffuse leptomeningeal nodular enhancement of the cervical, thoracic, and cauda equina nerve roots [Figure 1d-f].
Hematoxylin and eosin staining of the cauda equina demonstrating: (a, x100) pleomorphic spindle cells with prominent nucleoli, mitotic figures (b, x1250), and melanin pigment. Spreading of neoplastic cells along subpial and perivascular spaces (c, x100). Immunohistochemical stains for melanoma cocktail including Melan-A demonstrate cytoplasmic reactivity (d)
SNI-5-147-g002.jpg
PMC4209706_01_SNI-5-147-g002.jpg
F2
Frozen section of the nerve root demonstrated pigmented cells, and final surgical pathology revealed primary leptomeningeal melanomatosis [Figure 2].
PMC4209706_02
Midline sagittal magnetic resonance images (MRI) of thoraco-lumbar area. (a) T1-weighted MRI shows the spinal cord tumor at the level of T12, which has high signal intensity relative to that of the cord and combined syrinx. (b) Contrast-enhanced T1-weighted MRI image shows homogenous enhancement
SNI-5-147-g003.jpg
PMC4209706_02_SNI-5-147-g003.jpg
F3
Spinal MRI showed an expansile intramedullary mass involving the lower thoracic spinal cord and the conus medullaris from T11 to L1, isointense on T1-weighted imaging, and homogenously enhancing following gadolinium injection [Figure 3].
Photomicrograph shows spindle cells with large pleomorphic nuclei (a, H and E, x20), melanin pigment, and mitoses (b, H and E, x40). Immunohistochemical stains for melanoma cocktail including Melan-A (c) and S-100 brown chromagen (d) reveal cytoplasmic reactivity (H and E)
SNI-5-147-g004.jpg
PMC4209706_02_SNI-5-147-g004.jpg
F4
Pathology revealed a highly cellular tumor with spindle cell morphology and abundant dark pigmentation [Figure 4].