The central nervous system can be affected by melanocytic lesions ranging from diffuse neurocutaneous melanosis, to a focal and benign neoplasm (melanocytoma), and to an overtly malignant tumor (melanoma). Central nervous system primary malignant melanoma accounts for approximately 1% of all melanomas. Primary spinal melanomas are even more unusual and they arises from the leptomeninges or dura mater. When it concerns the leptomeninges may be involved both the brain and spinal cord.
The involvement of the basal cisterns causes hydrocephalus, intracerebral subarachnoid hemorrhage. Unusually are described cases of primary melanoma of the pineal gland. The melanomas that metastasize the brain primarily affect the cerebral hemispheres, while metastases are rare in the spinal cord (they are often incurable and surgery or radiotherapy can only reduce the size of the tumor). The use of steroids can reduce symptoms induced by edema.
Neurocutaneous melanosis is a rare congenital syndrome characterized by the presence of large or multiple congenital melanocytic nevi and benign or malignant pigment cell tumors of the leptomeninges; about 200000 people suffers of neurocutaneous melanosis in United States and it represents an error in the morphogenesis of the embryonal neuroectoderm. Frequent complications are: hydrocephalus, epilepsy, cranial nerve dysfunction, signs of involvement of the spinal cord or spinal roots.
By Nicola Angelotti, Dermatologist, Massa, Italy