Focus on melanotic neuroectodermal tumor of infancy

Melanotic neuroectodermal tumor of infancy (MNTI) is a very rare benign neoplasm of probable neurocristic origin. It primarily affects children in the first year of life, with the median age at diagnosis of 4.5 months (range 0–804 months). It usually presents as a fast-growing, painless tumor developing within maxilla, skull bones or mandible but other locations are also possible, especially in older children. The cornerstone of treatment of MNTI is surgery, however local relapses after incomplete tumor excision are common, particularly in patients younger than 2 months of age. Rare cases of multiple recurrent, inoperable or metastatic MNTI pose therapeutic challenges. In such clinical scenarios, various regimens of neoadjuvant chemotherapy based on schemes for neuroblastoma or Ewing sarcoma have been used with partial regressions in some patients, enabling less mutilating delayed surgery. The use of radiotherapy is limited due to very young age of patients with MNTI. No targeted therapies have been found useful so far. Long-term prognosis of localized MNTI is favorable. However, extensive or recurrent lesions can result in functional or esthetic sequelae after surgical removal. Rare cases of malignant/metastatic tumors and MNTI diagnosed in older children have unfavorable outcomes. Further collaborative studies to establish standards of management in patients with MNTI are necessary to improve outcomes and diminish sequelae of surgery. This article presents a literature review on this very rare tumor entity, re-evaluated in the light of the experience gained in the national working groups joined together within the European Cooperative Study Group in Pediatric Rare Tumors (EXPeRT).