Melanotic Neuroectodermal Tumor of Infancy
Author: William M Carpenter, DDS, MS, Professor, Chairman, Department of Pathology and Medicine, University of the Pacific Arthur A Dugoni School of Dentistry
Contributor Information and Disclosures
Updated: Sep 1, 2009
Background
Melanotic neuroectodermal tumor of infancy (MNTI) is a relatively uncommon osteolytic-pigmented neoplasm that primarily affects the jaws of newborn infants. The lesion has had an interesting history since its initial description by Krompecher in 1918 as a congenital melanocarcinoma.1 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 epithelial odontoma, pigmented teratoma, atypical melanoblastoma, melanotic adamantinoma, pigmented epulis, retinal choristoma, melanoameloblastoma, and retinoblastic teratoma. 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.2Since 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.
Pathophysiology
Several patients with melanotic neuroectodermal tumor of infancy (MNTI) have demonstrated a high urinary excretion of VMA. 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 urinary VMA is not diagnostic for MNTI.
Frequency
United States
Approximately 200 cases of melanotic neuroectodermal tumor of infancy (MNTI) have been reported in the literature. An exact number is difficult to discern because of the variety of terms that have been applied to the lesion in the past.3
Sex
The sexual predilection for melanotic neuroectodermal tumor of infancy (MNTI) is nearly equal, with a male-to-female ratio of 6:7.
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. The mean age of patients with melanotic neuroectodermal tumor of infancy (MNTI) is 4.3 months. Although extremely rare, a few cases of MNTI have been reported in adults, notably, a 23-year-old man, a 24-year-old woman, and a 67-year-old woman.
Clinical
History
* Although melanotic neuroectodermal tumor of infancy (MNTI) is classified as a benign lesion, it is often clinically worrisome because of its rapid onset and alarming local growth rate.
* Often, sucking and feeding are impaired secondary to the swelling.
* The patient is usually asymptomatic.
Physical
* The intraoral lesion appears as a sessile, lobulated mass, often reaching 2-4 cm in diameter by the time of diagnosis.
* No thrill or pulse can be elicited from the MNTI. Although the lesion expands rapidly, the overlying mucosa remains intact.
* More than 90% of MNTI occur in the head and neck region, with most on the anterior part of the maxillary ridge. Other common sites include the skull, the mandible, the epididymis, and the brain.4Rare lesions have been reported in the shoulder, the skin, the femur, the mediastinum, and the uterus.
* All but 2 of the reported cases have been solitary lesions.