Case of the Month: February, 2012, Page 4

Explanation

  • Distal metastasis is not common.

Discussion

MelanoticNeuroectodermal Tumor of Infancy (MNTI) is a rare neural crest tumor that most often involves the maxilla and jaw of newborn infants. This is an extremely rare tumor with approximately 200 cases being reported since its categorization in the early 1980s. The expansive, destructive, and rapid growth of MNTI and its effects on the surrounding tissues are the most obvious clinical features. Currently, it is classified in the group of primitive neuroectodermal tumors.

Several patients with MNTI have demonstrated a high urinary excretion of VMA, which adds credence to a neural crest origin as elevated VMA has been reported in neuroblastoma, ganglioneuroblastoma, pheochromocytoma, and other neural crest tumors. However, the presence of urinary VMA is not diagnostic and not always present.

Other less common sites of primary involvement include the skull, mandible and brain. The genital organs are the most frequent extracranial site. Complete early surgical excision is associated with good prognosis with reported recurrence rates of 10% to 20%. A malignancy rate of 3.2% is reported in the literature.Chemotherapy may be helpful in malignant forms.  Neuronal specific staining and immunohistochemistry confirm the diagnosis by demonstrating a biphasic cell population of large epitheloid cells containing melanin and small undifferentiated cells resembling neuroblasts.

The location of this lesion in the maxilla may be confused with odontogenic tumors and cysts, however these lesions usually occur beyond the age group of this tumor. Many nonodontogenic tumors are possible in the maxilla, including Langerhans cell histiocytosis, rhabdomyosarcoma, Ewing sarcoma, leukemia and lymphoma. However, these tumors are uncommon in infants. The presentation and clinical appearance of MNTI should render a clinical diagnosis with imaging used to confirm the location and extent of disease.

References

  • Statdx.com
  • Kruse-Losler B et al: Melanoticneuroectodermal tumor of infancy: systematic review of the literature and presentation of a case. Oral Surg Oral Med Oral Pathol Oral RadiolEndod. 102(2):204-16, 2006
  • Antunes AC et al: Melanoticneuroectodermal tumor of infancy: case report. ArqNeuropsiquiatr. 63(3A):670-2, 2005
  • Atkinson GO Jr et al: Melanoticneuroectodermal tumor of infancy. MR findings and a review of the literature.PediatrRadiol. 20(1-2):20-2, 1989
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