OT-07 * PRIMARY CENTRAL NERVOUS SYSTEM MELANOCYTIC LESIONS IN CHILDHOOD: EXPERIENCE AT NATIONAL INSTITUTE OF PEDIATRICS IN MEXICO

Abstract

INTRODUCTION: Primary central nervous system (CNS) melanocytic tumors are extremely uncommon in children. Annual incidence is 1 per 10 million population and carry a poor prognosis. Herein we present two cases treated at our institution, a leading pediatric oncology center in Mexico. METHODS: Our first patient was a 1 year-old female who began with non-convulsive status epilepticus and no fever history. Right frontoparietal leptomeningeal enhancement was evident on MRI, and a primary leptomeningeal melanoma was diagnosed according to biopsy. Radiotherapy did not improved her condition and further neurologic deterioration ensued. The second patient was a 6 year old male with a history of headache and vomiting, and left sided hemiparesis was evident at admission. MRI showed an ill-defined right temporal lobe lesion with mass effect and leptomeningeal involment. Immature cells were isolated on cerebrospinal fluid (CSF) and a primary malignant melanocytic lesion was diagnosed on brain biopsy. Later he developed refractory status epilepticus and died of septic shock. DISCUSSION: Although melanocytes are normally present in the nervous system, primary melanocytic tumors are extremely uncommon, being less than 0.1% of all CNS tumors in children. Three mayor variants are distinguished: diffuse melanocytosis, meningeal melanocytoma and malignant melanoma. Complete surgical resection is not always possible, while the efficacy of radiotherapy and chemotherapy remain controversial. CONCLUSION: Our experience shows that these lesions are extremely rare in our population and cannot be safely resected. Diagnosis is made by biopsy exclusively and neurologic deterioration eventually occurs despite radiotherapy.