Primary Amelanotic Leptomeningeal Melanomatosis in a Child: A Rare but Severe Disease.
BACKGROUND
Primary leptomeningeal melanomatosis (PLM) is a rare and aggressive form of nonmetastatic invasion of leptomeninges by malignant melanocytic cells. Clinical presentation includes nonspecific meningism with various forms of cerebrospinal fluid circulation or absorption disorders leading to hydrocephalus.


METHODS
A 5-year-old child with PLM without neurocutaneous melanosis presented with cystic enlargement of the brainstem surrounding cisterns and hydrocephalus requiring occipitoaxial decompression and endoscopic cystostomy. Initial cerebrospinal fluid cytology screening and frontal meningeal and brain biopsy specimens showed negative results. The diagnosis of unpigmented (amelanotic) malignant melanocytic cells was made after a biopsy specimen of the bulbar leptomeninges was obtained. Despite continuous management of hydrocephalus and chemotherapy, the disease progressed, and the patient died 11 months after diagnosis.


CONCLUSIONS
To the best of our knowledge, this is the first report of an amelanotic form of PLM without association of neurocutaneous melanosis in a child. This case report illustrates the difficulty of diagnosis in the absence of cutaneous lesions and lack of melanin.
Pediatric Neurosurgery Unit, Neurological and Neurosurgical Hospital, Hospices Civils de Lyon, Lyon 1 University, Bron, France. Electronic address: alexandru.szathmari@chu-lyon.fr.
Alexandru
A
Szathmari
Pathological Center, Bron East Hospital Center, Hospices Civils de Lyon, Lyon 1 University, Bron, France.
Romain
R
Perbet
Department of Radiology, Neurological and Neurosurgical Hospital, Hospices Civils de Lyon, Lyon 1 University, Bron, France.
Marc
M
Hermier
Pediatric Neurosurgery Unit, Neurological and Neurosurgical Hospital, Hospices Civils de Lyon, Lyon 1 University, Bron, France.
Federico
F
Di Rocco
Institut d'hémato-oncologie pédiatrique, Lyon, France.
Didier
D
Frappaz
Pediatric Neurosurgery Unit, Neurological and Neurosurgical Hospital, Hospices Civils de Lyon, Lyon 1 University, Bron, France.
Carmine
C
Mottolese
D002675:Child, Preschool; D003399:Craniotomy; D004724:Endoscopy; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D018328:Melanoma, Amelanotic / Q000000981:diagnostic imaging / Q000601:surgery*; D008577:Meningeal Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D015898:Tomography Scanners, X-Ray Computed
Amelanotic central nervous system melanoma; Melanocytic tumors of the nervous system; Pediatric brain tumors; Primary leptomeningeal melanomatosis