title: [Melanocytoma and meningeal melanocytosis, similar but different lesions].
abstract: BACKGROUND
  Meningeal melanomatosis is an extra-axial well-encapsulated malignant tumour with diffuse meningeal growth and dark coloration (due to high melanin contents), while meningeal melanocytoma is the focalized benign variant. Melanocytic lesions may be secondary to melanoma or be histologically benign, however, their diffuse nature makes them impossible to cure. Melanocytosis is a diffuse tumour that can form solitary extra-axial tumours, which invades the parenchyma and presents signs of malignancy with increased mitosis and Ki67, observed in 1 to 6% of immunopathological exams. Melanoma of the leptomeninges, presents signs of malignancy with anaplastic cells, which cluster in fascicles of melanin in the cytoplasm, with more than 3 atypical mitoses per field and Ki67 presenting in more than 6% of the immunopathological fields analysed.
  
  
  METHODS
  We present the case of a patient with long-term meningeal melanomatosis, with progressive neurologic deficit and characteristic radiologic features, and another case of meningeal melanocytoma.
  
  
  CONCLUSIONS
  Benign melanocytic neoplasms of the central nervous system must be treated aggressively in the early phases with strict follow-up to avoid progression to advanced phases that do not respond to any treatment method. Unfortunately, the prognosis for malignant melanocytic lesions is very poor irrespective of the method of treatment given.
authors.affiliation: Servicio de Neurocirugía, Hospital Juárez de México, Ciudad de México, México. Electronic address: neuroendovascularpadilla@hotmail.com.
authors.forename: Felipe
authors.initials: F
authors.lastname: Padilla-Vázquez
authors.affiliation: Servicio de Neurocirugía, Hospital Juárez de México, Ciudad de México, México.
authors.forename: Víctor Hugo
authors.initials: VH
authors.lastname: Escobar-de la Garma
authors.affiliation: Servicio de Neurocirugía, Hospital Juárez de México, Ciudad de México, México.
authors.forename: Arturo
authors.initials: A
authors.lastname: Ayala-Arcipreste
authors.affiliation: Servicio de Neurocirugía, Hospital Juárez de México, Ciudad de México, México.
authors.forename: Rafael
authors.initials: R
authors.lastname: Mendizábal-Guerra
authors.affiliation: Servicio de Patología, Hospital Juárez de México, Ciudad de México, México.
authors.forename: Teresa
authors.initials: T
authors.lastname: Cuesta-Mejía
mesh_terms: D000328:Adult; D000951:Antigens, Neoplasm / Q000032:analysis; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008544:Melanocytes / Q000473:pathology*; D008545:Melanoma / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology*; D008577:Meningeal Neoplasms / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology*; D008578:Meninges / Q000473:pathology*; D008940:Mitotic Index; D059906:Neuroimaging; D010264:Paraplegia / Q000150:complications; D020127:Recovery of Function; D013117:Spinal Cord Compression / Q000209:etiology; D055815:Young Adult
chemical_list: D000951:Antigens, Neoplasm
keywords: Lesiones melanocíticas primarias; Melanin; Melanina; Melanocitoma meníngeo; Melanocitos; Melanocytes; Melanosis; Meningeal melanocytoma; Meningeal neoplasm; Neoplasia meníngea; Primary melanocytic lesions