Melanotic neuroectodermal tumor of infancy (MNTI) of the head and neck: A French multicenter study

Melanotic Neuroectodermal Tumor of Infancy: A Case Image

Melanotic neuroectodermal tumor of infancy (MNTI) is a rare benign neoplasm that can be mistaken for malignancies due to its unfamiliarity among clinicians and aggressive clinical appearance. We herein contributed by reporting an additional case of MNTI characterized by an extensive extraoral protrusion in a 2-month-old infant. The lesion involved the anterior maxilla, cheek, and infraorbital region, resulting the displacement of the nose to the contralateral side, and measuring approximately 10 cm in size. Surgical resection of the lesion was performed. After a 6-month follow-up, the patient has shown no evidence of recurrence. The rapid growth and aggressive behavior of MNTI emphasize the importance of an early diagnosis and prompt intervention in order to achieve favorable outcomes.

Long term follow-up results of enucleation as the definitive treatment for melanocytic neuroectodermal tumour of infancy and a review on its treatment

Introduction

Melanotic Neuroectodermal tumour of Infancy (MNTI) is a rare entity of pigmented neoplasms of head and neck region. It predominantly occurs within the first year of life. The authors present enucleation as the definitive surgical treatment, with reference to the five departmental cases of MNTI with no recurrence at 5years and 1year of follow-up of other 4 cases.

Case presentation

Five cases of MNTI (age group of 2.5months-7 months) presented to our department as a large bluish-brown non tender swelling protruding into the oral cavity. Radiologic imaging revealed a well-circumscribed solid-cystic enhancing lesion causing elevation of orbit and nasal obliteration in maxillary region and causing buccolingual expansion in mandible. The tumor was enucleated without any bony margin. Histopathological and immunohistochemical evaluation (EMA, Pan Cytokeratin, HMB45, S100, p53, ki67) were done. Patients were followed up at regular intervals and had no recurrence at mean 3years follow-up. A detailed mention of surgical pearls, differential diagnosis and a brief literature review are also done.

Conclusion

MNTI is a pigmented neoplasm that occurs in infants and in head and neck region mostly involves the upper alveolus and maxilla, followed by skull and mandible. Incisional biopsy is needed to confirm the tumour and rule out other malignant round cell tumours. Enucleation of the lesion is necessary without the need for any extra bony margin removal. Close long term follow up is necessary. Conservative surgical approach is usually the best first choice for MNTI treatment.

Melanotic neuroectodermal tumor of infancy: A narrative review of dental aspects

Melanotic neuroectodermal tumors of infancy (MNTI) are a rare type of benign tumor that affects the head and neck region. MNTI represents (68-80%) of the tumors in the maxillary region. This tumor is usually located in the alveolar crest, skull, mandible, and brain. Although this tumor is considered benign, it can grow rapidly, with a high risk of recurrence and interference with functions of infancy, such as feeding and breathing. It is also frequently harmful to the surrounding soft and hard tissues or adjacent sensitive vital structures. This study aimed to review the pathological, clinical presentation, and treatment of melanotic neuroectodermal tumors in infancy and the role of dentists in these cases.

A case report of melanotic neuroectodermal tumor of infancy complicated with congenital heart disease and hypothyroidism

To the best of our knowledge, thus far there are no reported cases of melanotic neuroectodermal tumor of infancy (MNTI) with multiple complications. In this case report, we describe the clinical phenotype of MNTI in a 9-month-old female infant associated with tetralogy of Fallot (TOF), a congenital heart defect, and congenital hypothyroidism (CH). Our study showed that the growth of MNTI was delayed by a lower dosage of levothyroxine (L-T4) that was prescribed to treat CH because of the presence of TOF, a severe congenital heart disease. However, the standardized dosage of L-T4 improved thyroid function but stimulated the rapid growth of MNTI. Our report demonstrated that treatment with L-T4 affects the progression of MNTI. Our findings demonstrated the role of thyroid hormone in MNTI growth and progression. Furthermore, our study suggested that the treatment of co-morbidities in children with MNTI requires careful consideration of their effects on the growth and progression of MNTI.

Malignant Superficial Mesenchymal Tumors in Children

Malignant superficial mesenchymal tumors are a very diverse group of neoplasms with few clinical and radiological discriminatory factors. Hence, some of these cancers are rarely suspected based on clinical and radiological grounds, others may be easily misdiagnosed, and the histological analysis of a biopsy or resection is central in the diagnostic process. In children, the age at presentation is a major element of the differential diagnosis. Some tumors have a very distinct epidemiology, while others may be seen at any age. More recently, the advances in molecular biology have greatly improved the diagnosis of mesenchymal tumors and new entities are still being described. In the present review, we provide an overview of the diversity of malignant superficial mesenchymal tumors in children, including new and/or rare entities. We discuss the important diagnostic features, be they clinical, histological, or molecular. Special attention was given to the genetic features of these tumors, particularly when they were helpful for the diagnosis or treatment.

Melanotic neuroectodermal tumor of infancy (MNTI) - A rare entity

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.

Clinical and imaging features of melanotic neuro-ectodermal tumor of infancy of the maxillary bone: report of four cases and review of the literature

Melanotic neuro-ectodermal tumor of infancy (MNTI) is an extremely rare tumor. The purpose of this study was to describe the imaging features of maxillary bone MNTIs and introduce the key points for clinical diagnosis of MNTI. We retrospectively reviewed four patients with histology-proven MNTIs arising from the maxillary bone. All patients underwent ultrasonic inspections, CT and/or MR scanning. Combined with previously literature, the imaging features were comprehensively evaluated and analyzed. All MNTIs showed a firm, non-ulcerated rapidly-growing soft-tissue swelling with pigmented (blue-colored or black-colored or gray-colored) mucosa. The onset ages were younger than 6 month-old. CT images showed osteolytic or expansive bone destruction of the involved maxillae, fragmentary cortical bone, "free-floating" tooth germs, with or without spiculated/sunburst periosteal reaction. The tumor appeared lightly hyper-intense on T2-weighted sequences, while isointense or lightly hypo-intense or lightly hyper-intense signal on T1-weighted sequences. Enhanced images all displayed heterogeneous enhancement. No metastasis features of lymph nodes or abdominal organs were demonstrated by cervical and abdominal ultrasonic inspections. As a conclusion, accurate recognition of the imaging features of MNTI combined with history and clinical manifestations (early infancy, painless, firm, pigmented mucosa, non-ulcerating lesion) can provide clues for diagnosis of this rare entity.

Melanotic neuroectodermal tumour of infancy - A case report and review of literature

Rationale:

Melanotic neuroectodermal tumour of infancy (MNTI) is universally described as a rare, benign, pigmented lesion which most frequently involves the maxilla. Its origin is well established to be in the neural crest cells. Due to the high recurrence rate and aggressive behaviour mimicking malignancy, it poses a great challenge in their diagnosis, treatment planning, and prognosis.

Patient Concern:

Two-year-old female with no known comorbidities was brought in with the chief complaint of a growing swelling in the upper lip region.

Diagnosis and Treatment:

She was taken up for resection of the tumour under general anaesthesia. The specimen was subjected to histological and immunological examination confirming the diagnosis of MNTI.

Outcome:

The postoperative period was uneventful. After regular follow-up, the patient showed satisfactory healing with no signs of recurrence.

Take-Away Lessons:

Based on our experience, we feel that the diagnosis of MNTI is mainly clinical. Early conservative surgical excision and regular follow-up provide an excellent result with good prognosis.

[Melanotic neuroectodermal tumor of infancy. Clinical case of large fontanel tumor and literature review]

Melanotic neuroectodermal tumor of infancy (MNTI) is a neonatal tumor with progressive growth and high recurrence rate. Aggressive growth and localization of tumor often lead to significant cosmetic defects of cranial and facial bones. The authors report MNTI in a 6-month-old boy with lesion of the large fontanel. Total resection was followed by recurrence after 3 weeks. Repeated resection with subsequent radiotherapy was performed. The follow-up period was 6 months after repeated resection. There was no tumor growth throughout this period. Considering this case and world experience, we can conclude that treatment strategy for MNTI is still unclear.

The Role of Chemotherapy in Management of Inoperable, Metastatic and/or Recurrent Melanotic Neuroectodermal Tumor of Infancy-Own Experience and Systematic Review

Simple Summary

Melanotic Neuroectodermal Tumor of Infancy (MNTI) is a very rare neoplasm that most commonly develops within maxilla in infants. It usually has a benign clinical course and is treated with only surgery. However, patients with large, inoperable, metastatic or multiply recurring MNTI may require systemic treatment. The role of pre- and post-surgery chemotherapy (CHT) in the management of MNTI is unclear. Here, we have presented the disease courses and outcomes of four infants treated with multidrug CHT due to inoperable/recurrent MNTI. Additionally, a systematic literature review was performed which revealed 38 similar cases in the last 42 years. Most children with primarily inoperable MNTI responded to CHT, which allowed physicians to perform complete, non-mutilating delayed surgery. However, it is still uncertain whether CHT administered after incomplete resection of MNTI prevents recurrence. This study aimed to contribute to the establishment of standards of management in patients with inoperable, metastatic or persistently recurring MNTIs, which are currently lacking.

Abstract

Melanotic Neuroectodermal Tumor of Infancy (MNTI) is a very rare pediatric neoplasm of neural crest origin. In most cases, it develops in infants as a localized tumor of the maxilla, and surgery is usually curative. In less than 10% of patients with inoperable, metastatic or persistently recurring MNTI, chemotherapy (CHT) may be considered; however, its role is still unclear. The aim of our study was to assess the efficacy of CHT in children with large, inoperable, metastatic and/or recurrent MNTI. Four such infants, treated with CHT in Polish and German centers of pediatric oncology, were presented. Additionally, a systematic literature search of the PubMed/MEDLINE, Scopus and Web of Science databases was performed, yielding 38 similar cases within the last 42 years. Neoadjuvant CHT, based mainly on the protocols for neuroblastoma, was often effective, allowing for complete delayed surgery in most cases. However, the role of adjuvant CHT in preventing recurrences after incomplete resection of MNTI remains unclear. Disseminated inoperable MNTI was almost universally associated with poor response to CHT and unfavorable outcome. Further investigations to elaborate standards of management in patients with inoperable, metastatic or persistently recurring MNTIs are necessary to improve outcomes.

Melanotic Neuroectodermal Tumor of Infancy: A Clinicopathological and BRAF V600E Mutation Study of 11 Cases

Purpose

To investigate the clinicopathological features and BRAF V600E mutation of melanotic neuroectodermal tumor of infancy (MNTI).

Materials and Methods

Eleven cases of MNTI diagnosed at the Department of Oral Pathology were collected. Clinicopathological characteristics were obtained from the medical records. Immunostaining was performed by immunohistochemistry (IHC). Amplification-Refractory Mutation System-qPCR (ARMS-qPCR) and Sanger Sequencing were used to detect BRAF V600E mutation.

Results

Of the 11 cases, 3 cases were female and 8 cases were male. The mean age of the first symptoms was 3.2 months (range: 1 to 6 months). Ten cases (90.9%) located in maxilla but only one (9.1%) in mandible. Most of the cases demonstrated well-defined mass with lytic bone destruction and tooth germ affecting radiologically. Histologically, MNTI was consisted of large polygonal melanin-producing epithelioid cells and small round neuroblast-like cells which arranged in irregular alveolar, tubuloglandular and fissured architecture. The epithelioid cells expressed Vim, Pan-CK, NSE and HMB45, while the smalls cells expressed Syn, NSE and scattered Vim. Most cases showed low Ki-67 index (range: <1% to 50%). None of the MNTI cases showed BRAF V600E mutation. Most cases were treated with enucleation (45.4%) or curettage (36.4%). Among the 11 cases, 6 cases had follow-up information, and 2 cases had recurrence lesions after surgery.

Conclusion

MNTI, an extremely rare tumor, mainly affects male infants with strong preference for maxilla. Distinct histopathological features and immunohistochemical profile are helpful to distinguish from other melanin-containing tumors and small round cell tumors. No BRAF V600E mutation in MNTI is detected in the present study and needs further investigations. The factors that contribute to the local recurrence of MNTI are controversial, but the close follow-up for the patients is recommended.

Vascularized Composite Parietal Bone Flap for Immediate Reconstruction of a Hemi-Maxillectomy Defect in an Infant

BACKGROUND

Surgical resection of maxillary tumors can result in defects that can be difficult to reconstruct by conventional means due to the complex functional and anatomic nature of the midface and lack of regional bone flap options in the head and neck. Many reconstructive methods have been used to repair maxillary defects, but the ideal technique for the reconstruction of hemi-maxillectomy defects in growing pediatric patients has yet to be determined.

METHODS

The authors present a rare pediatric patient with melanotic neuroectodermal tumor of infancy resulting in a hemi-maxillectomy defect after resection that was reconstructed using a pedicled vascularized composite flap consisting of temporalis muscle, pericranium, and parietal bone.

RESULTS

The patient achieved successful long-term bony reconstruction of his right maxilla with this flap. Stable skeletal fixation with adequate orbital support was maintained over a >3-year follow-up period.

CONCLUSION

A vascularized composite parietal bone flap is a reliable reconstructive option for reconstruction of large maxillectomy defects providing low donor-site morbidity, adequate globe support, excellent long-term skeletal stability, and malar symmetry in rapidly growing pediatric patients. Successful reconstruction for a rare patient with maxillary melanotic neuroectodermal tumor of infancy requiring hemi-maxillectomy was demonstrated with >3-year follow-up.

Calvarial Melanotic Neuroectodermal Tumor of Infancy with Rhabdomyosarcomatous differentiation-A Rare Case

BACKGROUND

Malignant neuroectodermal tumor of infancy is a rare neural crest cell-derived neoplasm of infants. Histologically, melanotic neuroectodermal tumor of infancy usually consists of 2 types of cells: neuroblast-like and melanocyte-like cells. Here we present a rare case of melanotic neuroectodermal tumor of infancy containing a third type of cell population, that is, rhabdomyoblasts in addition to the above two.

CASE DESCRIPTION

We report a case of a 10-month-old female child who was brought to us with complaints of swelling over the right forehead for the last 9 months, which started increasing in size rapidly 3 months before presenting to us. Noncontrast computed tomography scan showed a large well-defined extra-axial lesion in the right frontotemporal region. The child underwent an open biopsy under general anesthesia. Histopathological sections showed a malignant small round cell tumor consisting of hyperchromatic cells lying in sheets and lobules separated by fibrous septae. The patient underwent 7 cycles of neoadjuvant chemotherapy over a period of 2 months. The patient underwent right frontotemporal craniotomy and gross total excision of the lesion as a definitive surgery. Postoperatively, the patient was stable, and there was no new deficit. Histopathology revealed neuroblast-like and melanocyte-like cells with rhabdomyosarcomatous differentiation. The patient received chemotherapy in the postoperative period. The patient had recurrence of the tumor and died 8 months after the surgery.

CONCLUSIONS

Calvarial malignant neuroectodermal tumor of infancy with rhabdomyosarcomatous differentiation is a rare entity with no cases being reported before. Neoadjuvant chemotherapy with surgical excision can be a promising modality of treatment.

The recurrence of the melanotic neuroectodermal tumour of infancy: an unusual presentation of a rare tumour

The melanotic neuroectodermal tumour of infancy (MNTI), also known as melanotic progonoma, is a rare neoplasm derived from neural crest cells. Although it is fundamentally benign, the tumour may present a locally aggressive behaviour, characterised by a rapid progression and a destructive invasion of adjacent structures, hence causing deformities. Unfortunately, perhaps due to the low incidence of this type of tumour, the published cases in the literature do not characterise the factors that imply the malignant or recurrent behaviour of the disease, nor the therapy to conduct these cases. Here, we report a rare case of a recurrent benign MNTI, approached unusually with a favourable outcome.

Melanotic neuroectodermal tumor of infancy to the skull: case-based review

BACKGROUND

Melanotic neuroectodermal tumor of infancy (MNTI) is a rare tumor, which usually occurs in infants under the age of one. Early diagnosis and radical surgery seem to be critical for long-term cure.

CASE PRESENTATION

We describe a case of a 4-month-old boy with a MNTI to the skull. The mass was first noticed at 4 month of age and grew very rapidly over a time of 2 weeks. Initially, a fine needle biopsy ruled out a sarcoma and led to the diagnosis. The tumor originated from the sphenoid wing and infiltrated the frontotemporal bone, the lateral wall of the right orbit, and the underlying dura mater. A total excision of the tumor, including the adjacent bone and dura, was achieved. Reconstruction of the bone was performed using absorbable plates and Tutobone. Histology confirmed the initial diagnosis, while molecular diagnosis showed high conformity of the MNTI with medulloblastoma group 3. The patient recovered well, while the reconstruction led to a good cosmetic result. A local recurrence occurred leading to a single-dose chemotherapy with Vincristine and a second surgery after 15 weeks. Thereafter, the patient developed recurrent large pseudomeningocele, which was treated by multiple shunt procedures and finally reconstruction of the bone using Palacos. Radiological follow-up 3 months after the second resection showed no tumor recurrence.

CONCLUSION

Radical surgery for MNTI is to date the gold standard since it seems to minimize recurrence rates. Because of the rapid and destructive growth within the bone, reconstruction is necessary, which can be very challenging in infants.

Melanotic neuroectodermal tumour of infancy: Refining the surgical approach

Melanotic neuroectodermal tumours of infancy (MNTI) are particularly rare and although predominantly benign, are infiltrative and locally aggressive. Presenting in the first year of life, prompt diagnosis and effective management are critical in minimizing morbidity and the risk of recurrence. A retrospective review of 11 MNTI managed at Great Ormond Street Hospital (GOSH) from 2000 to 2017 was undertaken. Eight tumours presented in the maxilla, two in the skull and one in the mandible. The primary modality of treatment was surgery in 10 cases with one patient receiving neoadjuvant chemotherapy. In spite of microscopically incomplete resection in seven cases, only three recurred. Overall, there was a local recurrence rate of 27% with no distant metastases noted. Disease-free survival was 100% with a follow-up ranging from 0.75 to 17 years (median 5 years). Taking our results in conjunction with the available literature, there is a role for conservative initial surgery of MNTI and this should be coupled with delayed reconstruction and intensive short-term follow-up. We propose an adapted treatment algorithm that aims to balance the risk of recurrence and malignant change with surgical morbidity in an infant population.

Melanotic Neuroectodermal Tumor of Infancy

Context.—

Melanotic neuroectodermal tumor of infancy, albeit rare and generally regarded as benign, is an important tumor to recognize because of its rapid growth, potential for local recurrence, and small round blue cell morphology, which can lead to misdiagnosis of a malignant neoplasm.

Objective.—

To review its clinical presentation and immunomorphologic findings, and discuss common entities in the differential diagnosis.

Data Sources.—

The study involved PubMed searches, including multiple review articles, case studies, retrospective studies, selected book chapters, and University of Michigan cases.

Conclusions.—

Melanotic neuroectodermal tumor of infancy most commonly occurs in the bones of the head and neck region during the first year of life, but it can also present in other locations, including the central nervous system, testes, ovaries, and subcutaneous soft tissues. Histologically, it is composed of a biphasic population of cells, consisting of epithelioid melanin-producing cells and primitive neurogenic cells in a fibrocollagenous stroma. These microscopic findings, especially in small biopsies, can lead to a broad differential diagnosis that includes malignant small round blue cell tumors and malignant melanoma. Melanotic neuroectodermal tumor of infancy commonly has an infiltrative growth pattern, and anatomic constraints often lead to incomplete resection and local recurrence, requiring multiple surgical operations. Because melanotic neuroectodermal tumor of infancy can mimic a more aggressive and aggressively treated malignancy, recognition of this rare tumor is very crucial for pathologists.