Volume 6, Issue 3 , Pages 140-142, September 2011
Melanotic neuroectodermal tumor of infancy—A report of two cases
Article Outline
Abstract
The melanotic neuroectodermal tumor of infancy (MNTI) is a rare childhood neoplasm with a classical clinical presentation. It appears as a rapidly enlarging pigmented mass in the upper jaw and can be easily mistaken for a malignant neoplasm. Although possessing an aggressive growth rate and radiographic appearance, the MNTI almost always behaves in a benign fashion and can be treated with local excision. However, few cases of malignant transformation and recurrences have been reported in literature and that makes follow-up very important. This paper describes two cases of MNTI with classical histological presentation.
Keywords: Infant, Pigmented, Neuroectodermal
1. 1 Introduction
Melanotic neuroectodermal tumor of infancy (MNTI) is a relatively uncommon osteolytic-pigmented neoplasm that primarily affects the jaws of newborn infants and was first described by Krompecher [1] in 1918 as a congenital melanocarcinoma and so far more than 250 cases have been reported in the medical literature. The lesion has been reported under a variety of different names in an attempt to identify the cell of origin. Some of the terms applied to this lesion included pigmented ameloblastoma, retinal anlage tumor, melanotic progonoma, melanotic epithelial odontoma, atypical melanoblastoma, pigmented epulis [2], [3], [4]. These terms reflected theories of suspected origin from the odontogenic apparatus, the pigmented anlage of the retina, or the sensory neuroectodermal tissues. It was Borello and Gorlin [5] in 1966 who reported a case with high urinary excretion of vanillylmandelic acid (VMA), suggesting a neural crest origin, and they proposed the term melanotic neuroectodermal tumor of infancy.
It is a locally aggressive, benign lesion of neural crest origin that occurs exclusively in infants younger than one year of age [6]. It occurs most commonly on the anterior part of the maxillary ridge [7]. Other common sites of involvement are skull, mandible, epididymus and the brain [8]. It may present as a multilocular lesion. The average recurrence rate is 15–20% but it may be as high as 50% [9]. In very rare instances malignant transformation has also been reported [8], [9], [10]. So a careful, long-term follow-up is required.
2. 2 Case reports
Case 1: A five months old first born male infant presented with a swelling in the anterior region of the maxillary alveolus (Fig. 1). The lesion had been initially noticed by parents two months back and had been gradually increasing in size since then. On examination a smooth, firm, nontender, nonpulsatile, nonreducible, noncompressible and nonfluctuant swelling with blackish pigmentation was present in the anterior part of the maxillary alveolus. Routine investigations were normal. There was no finding on aspiration. Incisional biopsy was performed from the most representative site of the lesion. Sections stained with H&E revealed distinct biphasic pattern (Fig. 2). The peripheral portion of the lesion contained large polygonal cells arranged in sheets or alveoli like structures. These large cells had abundant pale cytoplasm and pale nuclei with finely dispersed chromatin. These cells also contained the melanin pigment that gave the lesion its blue-black clinical appearance. The central portion contained lymphocyte like cells with small, dark nuclei. Immunohistochemical studies showed positive reaction for neuron specific enolase and HMB4 (Fig. 3). These histological and immunochemistry findings were consistent with diagnosis of MNTI.
Fig. 1.
Clinical picture showing a large growth in ant. alveolar ridge.
Fig. 2.
H&E stained section revealing biphasic pattern.
Fig. 3.
Immunohistochemistry with neuron specific enolase.
Case 2: A six months old male child presented with a swelling in upper front region for last two months which gradually increased to attain the present size. On clinical examination a smooth surfaced, mucosal colored growth of size 2
cm×2cm was protruding from oral cavity. There was stretching of upper lip and a compression of lower lip by the swelling. The swelling was localized, firm, well defined, nontender, nonpulsatile, nonreducible, noncompressible and nonfluctuant. Aspiration was negative. Maxillary occlusal X-ray showed ill defined radiolucency with interspersed hazy radio opacity in maxillary anterior region (Fig. 4). An incisional biopsy was performed and histological features were same as already discussed.
Fig. 4.
Occlusal X-ray.
The confirmative diagnosis in both cases was melanotic neuroectodermal tumor of infancy and patients were referred to the department of pediatric surgery where complete excision of the lesion was done. Patients were kept on follow-up at regular interval of every six months for a period of two years and there was no evidence of any recurrence.
3. 3 Discussion
MNTI was first described in 1918 by Krompecher [1] and is reported under a variety of names such as pigmented ameloblastoma [2], [3], [4] retinal anlage tumor [11], melanotic prognoma [12] or pigmented epulis. There are three theories of origin for this tumor and these are from the odontogenic apparatus, pigmented anlage of the retina or the sensory neuroectodermal tissues. In 1966, Borello and Gorlin [5] reported a case with high urinary excretion of vanillyl mandelic acid (VMA) suggesting a neural crest origin and they proposed the term melanotic neuroectodermal tumor of infancy.
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, the odontogenic cysts occur in an older age group. Congenital epulis of the newborn is another lesion that can occur in the children of same age group and at the same location. Many nonodontogenic tumors like Langerhans cell histiocytosis, rhabdomyosarcoma, Ewing sarcoma, and lymphoma are also common in young children.
The histologic appearance of MNTI is unique and a distinct biphasic pattern exists. One portion of the lesion contains large polygonal cells which contain melanin pigment that gives the MNTI its blue-black clinical appearance. The cuboidal polygonal cells are at the periphery of the alveolar spaces, while the central portion contains the characteristic small lymphocyte like cells.
The treatment of choice for melanotic neuroectodermal tumor of infancy (MNTI) is surgical excision, and it is usually curative. This treatment can usually be accomplished with a partial maxillectomy. Teeth, developing teeth, and the adjacent bone must be sacrificed when they are present near the borders of MNTI. The recurrence rate is 15–20% [9]. The recurrent lesions, possibly secondary to inadequate excision or multicentricity, usually occur within the first year after surgery. Although MNTI is an aggressive benign tumor, malignant variants have been reported, ranging from 1.5% to 2.1% [10].
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PII: S1871-4048(10)00043-2
doi:10.1016/j.pedex.2010.05.009
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Volume 6, Issue 3 , Pages 140-142, September 2011
