Melanotic neuroectodermal tumour of infancy: A case report and review of the aetiopathogenic hypotheses

Abstract

The case of a 2-month-old healthy infant without relevant medical history. The patient was referred due to the aggravation of a swelling occupying the left half of the anterior maxilla. This lesion became visible approximately one month ago; it involved the buccal gingiva and alveolar bone, including the deciduous tooth germs 6.1 and 6.2. The swelling had dimensions of 20 mm x 20 mm. The surgical excision was performed under general anesthesia. The tooth buds of 6.1 and 6.2 were closely related to the tumour and so were removed. The lesion was entirely enucleated. The pathology of the lesion confirmed a melanotic neuroectodermal tumour of infancy. The melanotic neuroectodermal tumour of infancy (MNTI) has been described as a rare benign pigmented painless swelling that usually occurs in the anterior region of the maxilla and in the incisor region. The histological examination showed small basophilic cells, many containing melanin pigmentation within the cytoplasm, with a second population of larger cubical cells with abundant cytoplasm, arranged in alveolar or adenoid clusters. According to Krompecher this tumour derives from epithelial nests evolved at the time of embryonic fusion of the facial processes. It has also been suggested that the tumour arises from the retinal anlage by a pinching-off process of neuroepithelium during the formation of embryonic eye. More recently, the presence of high levels of vanillylmandelic acid suggest a neural origin of the tumour.

Melanotic neuroectodermal tumor of infancy: A rare case report with differential diagnosis and review of the literature

“…Melanotic neuroectodermal tumor of infancy (MNTI) is a rare benign, non-ulcerative, painless, rapid expansile tumefaction of neural crest origin[1–3] with a high recurrence rate. [4] The rate of recurrence has been estimated at 15%, and the rate of malignant transformation at 6.6%.…”

Melanotic Neuroectodermal Tumor of Infancy Arising in the Temporal Bone

“…Most tumors were iso/hypointense with focal areas of hyperintensity on T1-and T2-weighted magnetic resonance images, and showed intense enhancement after intravenous gadolinium administration. 1,3,4,9 Although uncommon, the typical pattern of T1-shortening because of melanin deposition was helpful in diagnosis of this lesion. 10 Clinical and radiologic findings can suggest a diagnosis of melanotic neuroectodermal tumor of infancy, but histopathologic and immunohistochemical examination are required for a definite diagnosis.…”

“…1,3,6,7 Occasionally, some patients can show increased vanillyl mandelic acid, particularly with aggressive tumors, and the level of vanillyl mandelic acid can return to normal after tumor removal as seen in our case, suggestive of its neural crest origin. 1,3 The plain radiograph usually shows a well-defined radiolucent, expansile lesion with or without osteogenic reaction, and irregular margins can be observed in aggressive tumors. 1,3,4 CT scan generally revealed an expansile hyperdense lesion with internal soft-tissue density content and areas of hyperostosis.…”

Histogenetic Concepts, Terminology and Categorization of Biphasic Tumours of the Oral and Maxillofacial Region

“…[4] Collision, Combination, conversion and Composition theories of biphasic tumors [6] Divergent histogenesis theory of Carcinosarcomas [7] Tumorigenesis in Nasopharyngeal carcinomas [8] Biphasic nature in Epithelial myoepithelial Carcinoma [9] Two cell types in Mesenchymal Chondrosarcoma [10] Biphasic populations in Melanotic Neuroectodermal Tumor of Infancy [11] Mimicking biphasic natue of myofibroblastomas [12,13] Biphasic pattern of Neurilemmoma [14] [Table/ Fig-1]: Concepts of biphasic tumors in Oral and Maxillofacial Region polyclonal nature of tumourigenesis and it suggests that origin of carcinosarcomas is from two or more stem cells. The divergence hypothesis supports the monoclonal nature of tumourigenesis and it suggests that origin of carcinosarcomas is from a single totipotential stem cell that differentiates into separate epithelial and mesenchymal components [7].…”

“…Microscopically, it is characterized by a biphasic population of pigmented and non-pigmented cells in a dense fibrous connective tissue stroma [11]. The tumour is recognized by the presence of epithelial-like cells that are arranged in small islands, which outline acinar or glandular structures.…”