|Year : 2022 | Volume
| Issue : 3 | Page : 784-787
Melanotic neuroectodermal tumor of infancy (MNTI) – A rare entity
Divya Goel1, Sumaira Qayoom1, Madhu Mati Goel1, Jiledar Rawa2
1 Department of Pathology, KGMU, Lucknow, Uttar Pradesh, India
2 Department of Peadriatic Surgery, KGMU, Lucknow, Uttar Pradesh, India
|Date of Submission||12-May-2020|
|Date of Decision||16-Jul-2020|
|Date of Acceptance||01-Oct-2020|
|Date of Web Publication||25-Jul-2022|
Department of Pathology, KGMU, Lucknow - 226 003, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Melanotic neuroectodermal tumor of infancy is a rare pigmented pediatric tumor seen at craniofacial sites with the most common site being maxilla. This tumor arises from neural crest origin with a polyphenotypic expression of epithelial, neuroblastic, and melanotic markers. It is a locally aggressive tumor with rapid, expansile, and destructive growth. The tumor has fairly high chances of recurrence and malignant transformation, if not diagnosed and treated with time. There is no standard protocol for management owing to its rarity. Hereby, we present one such case of a 2-month-old male child with rapidly enlarging upper jaw swelling. The patient was treated with wide local excision, followed by two cycles of chemotherapy. The patient is in follow-up and doing well with no evidence of any local recurrence or metastasis till date.
Keywords: Immunohistochemistry, melanotic neuroectodermal tumor of infancy, recurrence, surgical excision
|How to cite this article:|
Goel D, Qayoom S, Goel MM, Rawa J. Melanotic neuroectodermal tumor of infancy (MNTI) – A rare entity. J Can Res Ther 2022;18:784-7
| > Introduction|| |
Melanotic neuroectodermal tumor of infancy is a rare tumor with the first case reported in 1918. Since then, <500 cases have been reported so far. This is a benign, locally aggressive tumor of infants with <1 year of age arising from neural crest cells, most commonly seen in the maxilla, and has a high recurrence rate. We report one such case with its clinic-pathological details.
| > Case Report|| |
A 2-month-old male baby presented with left-sided upper jaw swelling since birth. The swelling grew rapidly from pea sized to a large mass that led to difficulty in feeding. There was no history of fever/cold or abdominal distension. The baby was full-term healthy and cried spontaneously at birth. He was well immunized for the age. On general examination, there was no other significant abnormality or lymphadenopathy. On local examination, the swelling was firm, globular, and fixed with reddish, bluish pigmentation. It was nonpulsatile and nontender, measuring 4 cm × 3 cm [Figure 1]a. All biochemical investigations including routine hemogram, serum electrolyte levels, and kidney function tests were within normal limits
|Figure 1: Clinical and magnetic resonance imaging findings. A 4 cm × 4 cm firm globular swelling in the upper jaw (a), parasagittal contrast-enhanced computed tomography section shows a centrally hypodense enhancing mass lesion (*) of approximate size 4 cm × 4 cm arising from and encasing the upper jaw. The upper lip (white arrowhead), tongue (#), and lower lip and jaw (white arrowheads) are not involved by the mass (b). Gross image of an excised tumor showing well-defined lesion with blackish cut surface (c)|
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Computed tomography (CT) scan of head-neck [Figure 1]b showed a centrally hypodense enhancing mass lesion of approximate size 4 cm × 4 cm arising from and encasing the upper jaw. The mass did not involve the upper lip, tongue, and lower lip and jaw. The surgical resection was planned. Due to difficult intubation, tracheostomy was done preoperatively. Later, the patient was shifted to the neonatal intensive care unit for ventilator support. The postoperative period was uneventful, and he was extubated and accepted oral feeds well. The excised mass received in our histopathology department was a single globular soft-tissue piece measuring 4 cm × 3 cm × 2 cm, grossly. The outer surface was smooth, and the cut surface showed blackish areas [Figure 1]c. Histopathology revealed a well-defined mass lined by unremarkable mucosa. Tumor is disposed in lobules divided by thick fibrous septae. On high power, these nodules were seen composed of two distinct types of cell populations. One population was of small round blue cells having round hyperchromatic nuclei and scant cytoplasm. The second population of cells arranged on the periphery of the lobules was large epithelioid cells comprising abundant pale cytoplasm, round vesicular nuclei, and moderate cytoplasm with melanin pigment [Figure 2]. There was no atypical mitosis or necrosis. Considering the age of the patient and histomorphology of small round blue cells, immunohistochemistry panel was decided, and small tumor cells were diffusely positive for vimentin and synaptophysin, focally weak positive for S-100, while negative for LCA, desmin, and CD99. Large epithelioid cells were positive for HMB-45 and cytokeratin AE1/AE3. Mib-1 labeling index was <5% [Figure 3]. Based on histomorphology and immunohistochemistry findings, the diagnosis of melanotic neuroectodermal tumor of infancy was rendered with R0 resection.
|Figure 2: H and E section shows a well-defined pseudoencapsulated lesion lined by unremarkable mucosa (a, ×4), disposed in lobules divided by thick fibrous septae (b, ×4). On a higher power tumor was composed of two cell populations. One population was of small round blue cells (arrowhead) and other population of large cells arranged on the periphery of the lobules (Arrow) (c, ×10). The intracellular pigment can be seen in large cells (d, ×20, Arrow)|
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|Figure 3: ×20 shows cells positive for strongly positive for vimentin (a), synaptophysin (b). Large cells were positive for cytokeratin AE1/AE3 (c) and HMB45 (d). Ki67-labeling index is low (e). Tumor cells were weakly positive for S-100p (f) and negative for CD99 (g), LCA (h), and desmin (i)|
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| > Discussion|| |
Krompecher described the first case in 1918, and named it as melanocarcinoma. Later, Borello and Grolin in 1966 named it as melanotic neuroectodermal tumor of infancy, which is now universally accepted as a neuroectodermal tumor described under the WHO classification of tumors of the nasal cavity and paranasal sinuses in 2005. As the name itself suggest its neural crest origin, this tumor is usually seen in infants <1 year of age with slight female predilection in craniofacial sites with predominance in the maxilla (70%) followed by mandible (10%). The other less common sites are neurocranial dura, brain, epididymis, skin, and uterus. Clinically, all patients present with rapidly growing pigmented mass with no constitutional features. The compressive symptoms can be seen with respect to the location of the tumor. There may be elevated serum vanillylmandelic acid levels. In our case, levels were not done.
An expansile radiolucent lesion causing bony destruction is seen on the radiograph. On CT scan, the soft-tissue component is slightly hyperdense owing to the melanin, while magnetic resonance imaging (MRI) shows circumscribed enhancing iso- or hypointense mass on T1-and T2-weighted imaging., In our case, the lesion was hypodense encasing the upper jaw.
The differential diagnosis is developmental cysts, odontogenic lesions, and nonodontogenic neoplastic lesions such as rhabdomyosarcoma, Burkitt's lymphoma, Langerhans histiocytosis, and Ewing's sarcoma., On histology, the tumor shows a biphasic population of small neuroblasts like cells and large melanin-containing epithelioid cells disposed in alveolar architecture with nests and trabeculae intersected by fibrous septae. This biphasic morphology can be because of the mesodermal and ectodermal morphological features displayed by neural crest cells at different stages of development. Diagnosis can be rendered on clinical and histopathological features alone, but immunohistochemistry is necessary in approximately 46% of cases to confirm the diagnosis. On immunohistochemistry, the cells are positive for vimentin, synaptophysin, and NSE,, whereas negative for LCA, CD99, desmin, and myogenin. This rules out the other differential of round cell tumors. Large epithelioid cells are positive for pan-cytokeratin and HMB-45.
Management remains still a controversy. The surgical resection with 2–5 mm margin clearance is the mainstay of treatment. Chemotherapy and radiotherapy are not considered effective and have been reserved as adjuvant therapy in case of multiple recurrences or inadequate resection. Pontes et al. in 2018 in their review study found distant metastasis and local recurrence in 2.45% and 20.6% of cases, respectively. However, regional nodal metastasis is seen in <7% of cases. The recurrent lesion is more aggressive and resembles neuroblastoma on histopathology. Its malignant behavior and the overall prognosis are still unclear over the years. Studies done so far show patients with young age (<2 months), incomplete resection (R2), and maxillary localization had a higher recurrence and worse prognosis., Cases that recur are more aggressive and behave as neuroblastoma., Rao et al., in 2019, found that high Ki67 and CD99 expression correlates with aggressive behavior. Higashi et al. classified melanotic neuroectodermal tumor of infancy into two subtypes – an aggressive variant with predominantly small neuroblast-like cell component and slow growing subtype with large cells. Our patient was treated with adjuvant chemotherapy after resection because of the age of 2 months and significant small cell component and is in follow-up for the last 1 year. He is doing well with normal developmental milestones. This corroborates with a low proliferative index found in this case, though other prognostic markers do not correlate. The reason might be the early diagnosis and treatment of this case.
| > Conclusion|| |
Melanotic neuroectodermal tumor of infancy is a rare presentation with unclear clinical behavior and management. This should be kept in mind as one of the differentials of pediatric tumors at craniofacial sites. Early diagnosis and surgical treatment of the patient prevent the local spread and help in overall survival. Furthermore, it is important to do physical follow-up monthly and do an MRI every 6 months for 1 year after surgery as the chances of recurrence are more in this period.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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Conflicts of interest
There are no conflicts of interest.
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