Table 3.
MRI characteristics/abnormalities and location of melanocytosis
| References | MRI | Location of MRI abnormalities | Others | ||
|---|---|---|---|---|---|
| MRI performed n | MRI abnormalities n (%) | Leptomeningeal melanocytosis n (%) | Parenchymatous melanocytosis n (%) | Other findings than melanocytosis | |
| Group 1: General CMN group | |||||
| Ruiz-Maldonado et al. [17] | 13/13 | 7/13 (45%) No CNS melanocytosis | Not applicable | Not applicable |
Ventricular system asymmetry (n = 4) Calcifications (n = 2) Large cisterna magna (n = 2) Cortical atrophy, loss of cortico subcortical volume (n = 1) Right frontotemporal subgaleal collection (n = 1) |
| Foster et al. [9] | 42/46 | 14/42 (33%) (10 CNS melanocytosis) | 2/10 (20%) | 10/10 (100%) |
Middle cranial fossa arachnoid cyst (n = 1) Chiari type 1 malformation (n = 1) Tethered spinal cord secondary to a filum terminale fibrolipoma (n = 1) Transient crescentic enhancement over the right parietal convexity (that was not evident on repeated examination seven months later) (n = 1) |
| Bett et al. [48] | Unreported | Unreported | Unreported | Unreported |
Dandy-Walker complex (n = 5) Right hemimegalencephaly (n = 1) Cerebral cortical dysplasia (n = 1) Cerebral matrix haemorrhage (n = 1) Chiari malformation (n = 1) Choroid plexus tumour (n = 1) Encephalocraniocutaneous lipomatosis (n = 1) Tethered cord (n = 1) Unknown tumour (n = 1) |
| Chan et al. [25] |
7/39 Head (n = 5) Spine (n = 2) |
0/0 (0%) | Not applicable | Not applicable | Not applicable |
| Lovett et al. [20] | 27/61 (and 1 CT and 1 myelogram) | 7/27 (26%) (and 1 CT abnormality) | Unreported | Unreported |
CT scan: 2 hyperdense foci (n = 1) Spinal cord MRI: Mega cisterna magna, increased amount of fluid in post fossa with hydromyelia from C4-T6 (n = 1) Brain MRI: arachnoid cyst (n = 1) Ventriculomegaly with haemorrhagic changes, VP shunt, diffuse enhancement of meninges, intraparenchymal hematoma (n = 1) |
| Bekiesińska-Figatowska et al. [47] | 24/24 |
8/24 (33%) (CNS melanocytosis) |
4/7 (57%) | 7/7 (100%) | Neurofibromatosis type 1 (multiple multilevel roots neurofibromas on MRI) (n = 1) |
| Waelchli et al. [7] | 271/271 |
46/271 (17%) (36 (13%) CNS melanocytosis) |
3/36 (8%) | 35/36 (97%) |
Dandy-Walker malformation with hydrocephalus (n = 2) Lack of white matter bulk (n = 2) Larger ventricles (n = 2) Benign intradural tumour (n = 1) Choroid plexus papilloma (n = 1) Cortical thinning (n = 1) Extramedullary dural stranding (n = 1) Filum terminal lipoma (n = 1) Left frontal lobe meningioma (n = 1) Leptomeningeal disease (n = 1) Low volume inferior vermis (n = 1) Midline posterior fossa arachnoid cyst (n = 1) Right cerebellar astrocytoma (n = 1) Small right cerebellar hemisphere (n = 1) Spinal cord compression (n = 1) Venous angioma left cerebellar hemisphere (n = 1) |
| Viana et al. [56] | 11/57 | Unreported | Unreported | Unreported | Unreported |
| Wramp et al. [24] | 36/83 | 4/36 (11%) (2 CNS melanocytosis) | Unreported | Unreported | Unreported |
| Jakchairoongruang et al. [18] | 80/80 | 35/80 (41%) (33 CNS melanocytosis) | 5/33 (15%) | 33/33 (100%) |
Periventricular grey matter heterotopia (n = 3) Dysmorphic cerebellar hemispheres (n = 2) Small left-side ventral pons (n = 2) Small pons and cerebellum (n = 2) Corpus callosum hypogenesis (n = 1) Inferior vermian hypoplasia (n = 1) Small right cerebellar hemisphere (n = 1) Right temporal lobe polymicrogyria (n = 1) Vermian hypoplasia (n = 1) |
| Group 2: Only reporting on neurological signs and symptoms in patients with MRI abnormalities | |||||
| Bittencourt et al. [23] | 38/194 | 13/38 (34%) (CNS melanocytosis) | Unreported | Unreported | Dandy-Walker syndrome (n = 1) |
| Ramaswamy et al. [19] | 14/14 | 14/14 (100%) | 7/14 (54%) Diffuse leptomeningeal deposits | 8/14 (62%) |
Lower cervical benign spindle cell tumor (n = 1) Holocord arachnoid cyst (n = 1) Cervical/thoracic cyst (n = 1) Dorsal thoracic cyst (n = 1) |
| Price et al. [55] | Unreported | 12 (CNS melanocytosis) | Unreported | Unreported | Unreported |
| Qian et al. [21] | 13/13 | 13/13 (100%) (CNS melanocytosis) | 13/13 (100%) Diffuse leptomeningeal deposits | Unreported | Leptomeningeal thickening (n = 13) |
We identified two study groups. Ten studies reported on neurological signs and symptoms and MRI imaging in a general CMN population ‘general CMN group’ (2107 patients) and four studies reported on neurological signs and symptoms only in patients with MRI abnormalities ‘only reporting on neurological signs and symptoms in patients with MRI abnormalities’ (232 patients)
CMN, congenital melanocytic naevi; CNS, central nervous system