The first case MNTI to be reported in the literature was designated as “Congenital melanocarcinoma” by Krompecher[1
] in 1918. He described a pigmented tumor of the maxilla associated with a developing tooth and elements of dental lamina in a 2-month-old infant. In 1926, Mummery and Pitts[8
] reported a case of pigmented maxillary tumor in a 5-month-old girl. The characteristics of the tumor suggested that it arose from some aberration of the dental epithelium, and the term melanotic epithelial odontoma was introduced. Halpert and Patzer[9
] reported a similar tumor in 1947, which contained pigmented epithelium and was suggestive to be the ciliary body of the eye. Small unpigmented cells that resemble neuroblasts from the retinal neuroepithelium were also present. They suggested that the tumor arose from the entrapment of the retinal anlage in the embryologic fusion lines of the developing maxilla. Stowens[10
] reported three cases of a tumor, which he believed resembled the vomeronasal organ of Jacobson in several ways. In 1966, Borello and Gorlin[5
] reported a case of melanotic tumor in the maxilla of a 3-month-old boy. Before surgical removal of the tumor, there was increased urinary excretion of 3-methoxy-4-hydroxymandelicacid (VMA), which returned to normal after the tumor was removed. Because a high urinary level of VMA is also common in other tumors of neural crest origin, Borello and Gorlin believed that this was highly suggestive of a neural crest origin. Also, because this tumor is common in infancy, they recommended the term MNTI.
A high level of urinary VMA is useful for diagnosing tumors of neural crest origin.[5
The levels of VMA return to normal after excision of MNTI,[6
] as in the present case. However, VMA levels seem to have no relation to the tumor’s biological behavior.[12
The MNTI clinically presents as a rapidly growing, painless, expansile, unencapsulated partly pigmented mass, typically in the maxillary region.[13
] It tends to occur as a single lesion. However, multiple lesions have also been reported.[9
Conventional radiographs of bony lesions usually show radiolucency with or without irregular margins. It is typical of CT scans to reveal hyperdense masses, but hypodense variants have been reported as well. The CT can accurately define the extent of the lesion and thus provides a good basis for surgical planning. Magnetic resonance imaging shows a hypodense mass with focal areas of hyperdensity.[7
In addition to the typical clinical presentation, the cytology and histology are distinctive, showing a dual population of small neuroblastic cells and larger melanin-containing epithelial cells,[14
] as also seen in our case.
IHC markers are helpful in differentiating MNTI from embryonal rhabdomyosarcoma (desmin and myoglobin positive), Burkitt’s lymphoma (common leukocyte antigen positive) and malignant melanoma (HMB-45 and S-100 positive).[15
Immunohistochemically, reactivity for HMB-45 and synaptophysin in our case indicate melanocytic and neuroblastic differentiation of the tumor cells, confirming the diagnosis of MNTI.
The treatment of choice consists of complete surgical excision. Individuals with MNTI that are not amenable to surgical management alone may receive other modes of treatment.[9
] In general, this may be chemotherapy alone, chemotherapy with radiotherapy, chemotherapy before and after the surgical treatment, radiotherapy and surgical treatment or a combination of all. Chemotherapy may serve as an alternative or adjuvant option in the treatment of widely extended MNTIs.[7