Melanotic neuroectodermal tumor of infancy in the maxilla

Abstract

Melanotic neuroectodermal tumors of infancy (MNTIs) are rare fast-growing tumors with high recurrence rates. These tumors, which originate in the neural crest, commonly occur in the anterior maxilla of children under the age of one. Here, we describe an MNTI case in a two-month-old girl with increasing swelling in the left cheek. MNTI was diagnosed in this case following tomography and biopsy. The patient's histological and immunohistochemical profile indicated a remarkable combination of neural, melanocytic, and epithelial cell differentiation. One year following tumor excision, a follow-up examination revealed that the child exhibited no tumor recurrence. Approximately 260 cases of MNTI have been reported since this type of tumor was first described. In the present case, early diagnosis minimized the difficulties and risks associated with treatment and facilitated an optimal outcome. Despite complete surgical excision, careful followup is recommended. In addition, maxillary functional orthopedics and reconstruction may be necessary in cases of MNTI.

Figure 1

Upon an intraoral assessment, swelling in the left premaxilla alveolar ridge near the canine pillar (a) was observed. Preoperative tomography images (b) revealed a homogeneous hypodense tumor associated with the upper left central primary incisor. An image showing the one-year postoperative intraoral aspect (c). Postoperative tomography image presenting a maxilla defect but no lesion recurrence is shown (d).

Figure 2

Photomicrographs of histological and immunohistochemical findings. Nests containing biphasic cell populations within dense connective tissue are shown. The presence of small neuroblast-like cells with delicate fibrils between them (indicated by dashed arrows) and large melanin-containing cells (indicated by arrows) were observed (H&E, magnification ×400) (a). Large epithelial-like cells were positive for cytokeratin AE1/AE2 (b) (magnification ×100), epithelial membrane—EMA (c) (magnification ×400), and HMB45 (d) (magnification ×100). Both cell types were positive for vimentin, but the signal intensity was stronger in large cells (e). Both cell types were also positive for chromogranin, but the signal intensity was stronger in small cells (f) (magnification ×100). Synaptophysin was expressed by small neuroblast-like cells (magnification ×100) (g). Nuclear expression of Ki67 was also observed (magnification ×100) (h).