Melanotic Neuroectodermal Tumor of Infancy

Updated: Apr 10, 2017
  • Author: Leticia Ferreira, MS, DDS; Chief Editor: William D James, MD  more...
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Overview

Background

Melanotic neuroectodermal tumor of infancy (MNTI) is a relatively uncommon osteolytic-pigmented neoplasm that primarily affects the jaws of newborn infants. [1] The lesion has had an interesting history since its initial description by Krompecher in 1918 as a congenital melanocarcinoma. [2]

For the next 5 decades, the lesion was reported under a variety of different names as succeeding authors attempted to identify the cell of origin. Some of the terms applied to this lesion included pigmented ameloblastoma, retinal anlage tumor, melanotic progonoma, melanotic adamantinoma, and pigmented epulis of infancy. [3, 4, 5] These terms reflected theories of suspected origin from the odontogenic apparatus, the pigmented anlage of the retina, or the sensory neuroectodermal tissues.

In 1966, Borello and Gorlin reported a case with high urinary excretion of vanillylmandelic acid (VMA), suggesting a neural crest origin, and they proposed the term melanotic neuroectodermal tumor of infancy. [6] Since then, numerous histochemical, immunohistochemical, electron microscopic, and tissue culture studies have supported the neural crest origin and confirmed the preferred term of melanotic neuroectodermal tumor of infancy. [7, 8, 9, 10]

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Pathophysiology

Several patients with melanotic neuroectodermal tumor of infancy (MNTI) have demonstrated a high urinary excretion of VMA. [6, 11] This finding adds credence to a neural crest origin because elevated VMA has been reported in neuroblastoma, ganglioneuroblastoma, pheochromocytoma, and other neural crest tumors. However, the presence of elevated urinary VMA is not diagnostic for MNTI.

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Epidemiology

Frequency

Melanotic neuroectodermal tumor of infancy (MNTI) is a rare neoplasm and approximately 485 cases have been reported in the literature to date worldwide.

Sex

Melanotic neuroectodermal tumor of infancy (MNTI) has a slight male predilection, with a male-to-female ratio of 1.3:1. [12]

Age

Most patients, by some estimates more than 90%, present with the tumor in the first year of life, usually from age 1-6 months, with a peak between the second and sixth month of life. [13] A few cases of melanotic neuroectodermal tumor of infancy (MNTI) have been reported in adults, notably, a 23-year-old man, a 39-year-old woman, and a 67-year-old woman. [14, 15, 16] However, only 9% of cases are seen in patients older than 12 months. [17]

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Prognosis

Most melanotic neuroectodermal tumors of infancy (MNTIs) are benign and effectively managed by aggressive surgical excision. Reconstruction may be challenging. In a systematic review, a recurrence rate of 20% was found, with the highest relative risk for recidivation being found in the mandible and skull (33.3% and 31.8%, respectively). Most recurrences appear to occur within 4 weeks after the operation. A comprehensive systematic review of 472 cases of MNTI found that age at diagnosis is an important prognostic indicator in these tumors. Infants diagnosed within the first 2 months of birth have a shorter disease-free survival period and the recurrence tends to occur within only 6 months from treatment, while patients older then 4.5 months have minimal risk of recurrence. [12] Unfortunately, reports have shown that recurrent tumors tend to behave more aggressively and involve other anatomic structures such as the orbit and skull base. [18, 19] Additionally, a malignancy rate of 6.5% has been reported for these tumors, with most malignant cases occurring in the skull and brain. Only very few tumors produce metastases and death. [17]

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