Melanotic Neuroectodermal Tumor of Infancy Differential Diagnoses

Updated: Jun 19, 2018
  • Author: Leticia Ferreira, DDS, MS; Chief Editor: William D James, MD  more...
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DDx

Diagnostic Considerations

Consider clinical, radiographic, laboratory, and histologic findings when establishing a proper differential diagnosis for melanotic neuroectodermal tumor of infancy (MNTI). The MNTI often presents as a fast-growing lesion, suggesting a clinical impression of infection or malignant neoplasm. The location in the anterior aspect of the maxilla is consistent with a number of odontogenic cysts and tumors; however, odontogenic cysts (eg, periapical cyst, dentigerous cyst, odontogenic keratocyst, calcifying odontogenic cyst) occur in an older age group, teenaged through middle-aged adults. The same age differential is noted with respect to the more common odontogenic tumors (eg, ameloblastoma, odontoma, adenomatoid odontogenic tumor, calcifying epithelial odontogenic tumor, ameloblastic fibroma, odontogenic myxoma, odontogenic fibroma).

In addition to a diagnosis of MNTI, the young age of the patient and the maxillary alveolar ridge location are also compatible with a clinical diagnosis of congenital epulis of the newborn. However, this entity can be differentiated from the MNTI by its strong female predilection and involvement exclusively of the gingival soft tissues without destruction of the underlying maxillary bone. [1] Many nonodontogenic entities are possible in the jaws, including a central giant cell granuloma, ossifying fibroma, fibromatosis, fibrous dysplasia, hemangioma, arteriovenous malformation, craniopharyngioma, Langerhans cell histiocytosis, rhabdomyosarcoma, Ewing sarcoma, and lymphoma. However, only fibromatosis, Langerhans cell histiocytosis, rhabdomyosarcoma, Ewing sarcoma, and lymphoma are common in young children.

The radiographic appearance of a maxillary alveolar low-density radiolucency is consistent with any of the odontogenic cysts or tumors. Additionally, many of the aforementioned nonodontogenic lesions may also present with a radiographic appearance similar to that of MNTI.

Once a differential diagnosis is established from the clinical and radiographic findings, histologic evaluation is necessary to determine the final diagnosis. The histologic appearance of MNTI is usually that of a small, round blue cell neoplasm suggestive of neuroblastoma, rhabdomyosarcoma, Ewing sarcoma, lymphoma, desmoplastic small round cell tumor, and peripheral primitive neuroectodermal tumor. However, MNTIs can be differentiated from these more ominous entities by their biphasic population of cells, in which not only the small, dark cells are present, but also a second cell population, consisting of larger, polygonal, cells. These larger cells exhibit vesicular nuclei and granules of dark-brown melanin. The identification of this second cell population helps differentiate MNTI from other small, round, blue cell tumors. Although the histologic appearance is characteristic, special immunohistochemical stains may be used to make a definitive diagnosis.