Melanotic neuroectodermal tumor of infancy in the femur: a case report and review of the literature

Melanotic Neuroectodermal Tumour of Infancy

Melanotic neuroectodermal tumour of infancy (MNTI) is a locally aggressive neoplasm of neural crest origin. It is primarily a paediatric tumour, and 95% of the cases occur in children below 1 year. The tumour mainly affects the head and neck region. It shows a predilection for the craniofacial sites and the most common site affected is anterior maxilla. Microscopically, it is characterized by a biphasic population of neuroblastic cells and pigmented epithelial cells. Although generally considered as a benign tumour, it can invade the adjacent muscle and bone, causing destruction of the involved site. The rapidity in growth and the aggressive clinical behaviour of the tumour can be deceptive and hence lack of familiarity with the clinical characteristics of the tumour may often lead to an erroneous diagnosis of malignancy. The treatment of choice for MNTI is excision, and it is usually curative. Extensive surgery in a child may interfere with the normal growth and development of the facial structures and reconstruction can be very challenging in infants. Hence, early diagnosis is critical for the effective management. Clinical findings, histopathological features, and differential diagnosis of a classic case of melanotic neuroectodermal tumour of infancy are discussed.

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.

Melanotic Neuroectodermal Tumor of Infancy in the Ulna of an Infant: A Very Rare Tumor: A Case Report

CASE

A 4-month-old boy presented with a nontender swelling of the right proximal forearm of 2 months' duration. Radiological evaluation showed lytic lesion surrounded by sclerotic bone in the ulna with soft-tissue extension. Histopathological examination showed tumor of round and epithelioid cells containing melanin, interpreted as melanotic neuroectodermal tumor. The patient underwent a wide excision of the shaft of the ulna with creation of radioulnar synostosis. There is no recurrence 6 years after surgery.

CONCLUSION

Melanotic neuroectodermal tumor is rare in the appendicular skeleton and has to be differentiated from other round cell tumors and osteomyelitis. As far as we know, this is the first reported case in the ulna.

Melanotic neuroectodermal tumour of infancy presenting as a lytic lesion in femur: a rare tumour at a rare site with an unusual behaviour

Melanotic neuroectodermal tumour of infancy (MNTI) is an uncommon tumour, predominantly occurring in head and neck, mostly maxilla, but also in skull and mandible. Although a benign lesion, it is known to recur in 15%-27% of cases, and rarely, may undergo malignant transformation. We present a case of a 5-month-old female patient, who presented with a gradually progressive swelling in the right thigh. On imaging, an osteolytic lesion was seen, involving the metadiaphysis of shaft of right femur. A biopsy was performed, on which diagnosis of MNTI was made. MNTI is rarely seen in extremities. To the best of our knowledge, only six cases have been reported in femur, the present case being the seventh. The tumour showed spontaneous regression on follow-up in our patient, which has rarely been described. A knowledge of characteristic morphology and immunohistochemistry is the key to differentiate it from other tumours.

Spontaneous Regression of Diffuse Periosteal Melanotic Neuroectodermal Tumor of Infancy in the Tibia, With 13-Year Follow-up

Melanotic neuroectodermal tumor of infancy (MNTI) is a rare entity primarily affecting the craniofacial bones during the first year of life, with only 5 reported cases involving peripheral long bones. We herein present a case of MNTI in the tibia of an infant, with a somewhat atypical presentation, and a noteworthy clinical course characterized by progressive spontaneous resolution without therapy, thus sparing the child the trauma of amputation. There is no evidence of active residual or recurrent disease with 13-year follow-up. To the best of our knowledge, essentially all reported cases of MNTI have received empirical treatment, some at the price of mutilating surgery or fatal chemotherapy. We propose that the necessity of aggressive treatment be evaluated on a case-by-case basis, especially in patients with diffuse periosteal involvement, as in this patient. A trial of watchful waiting can be considered when treatment would involve substantial morbidity or risk of complications.

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.

A germline mutation of CDKN2A and a novel RPLP1-C19MC fusion detected in a rare melanotic neuroectodermal tumor of infancy: a case report

Background

Melanotic neuroectodermal tumor of infancy (MNTI) is exceptionally rare and occurs predominantly in the head and neck (92.8 % cases). The patient reported here is only the eighth case of MNTI presenting in an extremity, and the first reported in the fibula.

Case presentation

A 2-month-old female presented with a mass arising in the fibula. Exhaustive genomic, transcriptomic, epigenetic and pathological characterization was performed on the excised primary tumor and a derived cell line. Whole-exome analysis of genomic DNA from both the tumor and blood indicated no somatic, non-synonymous coding mutations within the tumor, but a heterozygous, unique germline, loss of function mutation in CDKN2A (p16^INK4A, D74A). SNP-array CGH on DNA samples revealed the tumor to be euploid, with no detectable gene copy number variants. Multiple chromosomal translocations were identified by RNA-Seq, and fusion genes included RPLP1-C19MC, potentially deregulating the C19MC cluster, an imprinted locus containing microRNA genes reactivated by gene fusion in embryonal tumors with multilayered rosettes. Since the presumed cell of origin of MNTI is from the neural crest, we also compared gene expression with a dataset from human neural crest cells and identified 185 genes with significantly different expression. Consistent with the melanotic phenotype of the tumor, elevated expression of tyrosinase was observed. Other highly expressed genes encoded muscle proteins and modulators of the extracellular matrix. A derived MNTI cell line was sensitive to inhibitors of lysine demethylase, but not to compounds targeting other epigenetic regulators.

Conclusions

In the absence of somatic copy number variations or mutations, the fully transformed phenotype of the MNTI may have arisen in infancy because of the combined effects of a germline CDKN2A mutation, tumor promoting somatic fusion genes and epigenetic deregulation. Very little is known about the etiology of MNTI and this report advances knowledge of these rare tumors by providing the first comprehensive genomic, transcriptomic and epigenetic characterization of a case.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2669-3) contains supplementary material, which is available to authorized users.

Mandibular melanotic neuroectodermal tumor of infancy: a role for neoadjuvant chemotherapy

Melanotic Neuroectodermal Tumor of Infancy (MNTI) is a rare, locally aggressive neoplasm with a predilection for the head and neck area, most commonly occurring in the maxilla. The vast majority of treatment modalities for all cases of MNTI to date have involved surgical intervention only, with just 9.6 % involving some sort of chemotherapy, radiotherapy, or a combination of the prior mentioned modalities. There is very limited information available regarding the use of neoadjuvant chemotherapy, due to its rare nature. In this report, a 4 month old girl presented to our clinic with a chief complaint of a large oral mass of about 2.5 months in duration. Intraoral examination showed an oral mass arising from the lingual aspect of inferior alveolar ridge with extensive mandibular invasion. The patient received three cycles of vincristine, Adriamycin, and cyclophosphamide as neodajuvant therapy. Upon completion, the tumor had decreased significantly in size. The patient was then scheduled for surgery and underwent surgical resection of the tumor. We were able to obtain adequate shrinkage of the tumor to allow better resectability, easier surgical access and a more minimally invasive approach with no lip split and a smaller neck incision. In conclusion, we have reported an extremely rare case of MNTI of the mandible that was successfully treated with neoadjuvant chemotherapy and surgical resection. This approach was advantageous to minimize the chance of recurrence and improve resectability in particularly large tumors, while maximizing functional outcomes and minimizing deformity.

Melanotic Neuroectodermal Tumor of Infancy in the Epididymis: A Brief Report and Review of the Role of Chemotherapy in Management

Melanotic neuroectodermal tumor of infancy is a rare benign tumor of neural crest origin. The tumor generally presents in the jawbones; however, it occasionally occurs in extracranial sites. Although 95% of these tumors present within the first year of life and 15% in extracranial locations, we report an unusual case of a 15-month-old male with melanotic neuroectodermal tumor of infancy of the epididymis. The patient underwent orchiectomy without adjuvant chemotherapy or radiation. Twenty months later, there was no sign of recurrence. In addition, we discuss the role of chemotherapy and radiation and the potential importance of molecular genetics in establishing guidelines for management.

Melanotic neuroectodermal tumor of infancy: a wolf in sheep's clothing

INTRODUCTION

The melanotic neuroectodermal tumor of infancy (MNTI) is an exceptionally rare neoplasm. Despite their potential for local invasion, MNTI are considered benign neoplasms. Sporadic cases have been reported of MNTI acting in a malignant fashion; however, the majority of these tumors were of extragnathic origin.

METHODS

A 2-month-old male presented with a rapidly expanding maxillary mass. The patient underwent excisional biopsy of the mass and a diagnosis of MNTI was returned. Tumor recurrence was appreciated postoperatively. Neoadjuvant chemotherapy was initiated to render it more amenable to surgical resection. Chemotherapy was suspended prematurely and the patient returned to the operating room for hemimaxillectomy. The postchemotherapy surgical pathology report demonstrated a unique mixed chemotherapy response.

DISCUSSION

This report highlights the aggressive nature of gnathic MNTI, the importance of early diagnosis and definitive intervention, and the mixed clinical and histologic response of the lesion to neoadjuvant chemotherapy.

Neurogenic tumors of soft tissue

Neurogenic tumors are an uncommon yet important category of soft tissue tumors in children and adolescents because of their frequent association with various genetic syndromes. The heterogeneous cellular composition of the peripheral nerve and the wide metaplastic capacity of the neural crest and its derivatives generate a variety of neoplasms with neurogenic differentiation. This article reviews the clinicopathologic features and differential diagnosis of neurogenic tumors in the first two decades of life, and highlights use of selected ancillary methods for diagnosis.

Melanotic neuroectodermal tumour of infancy: CT and MR findings

BACKGROUND

Melanotic neuroectodermal tumour of infancy (MNTI) is a rare neoplasm of neural crest origin.

OBJECTIVE

To describe three further cases of MNTI, with emphasis on CT and MRI findings.

MATERIALS AND METHODS

Data for children with histologically confirmed MNTI following biopsy or surgery were retrieved. Three children with available imaging at the time of diagnosis were included in the study.

RESULTS

All three children had primary tumour in the head and neck region: one in the maxilla, one in the occipital bone (extra-axial but with intracranial extension) and one with an unusual tumour growing exophytically from the subcutaneous tissues adjacent to the occipital bone. All tumours were iso/hypointense both on T1- and T2-weighted MRI, and showed marked contrast enhancement in their non-ossified components. CT allowed identification of bone destruction and remodelling.

CONCLUSION

Our findings are consistent with previously reported cases of MNTI regarding age at presentation and location in the head and neck region. Our MR findings did not demonstrate the typical pattern of T1-shortening expected from melanin deposition.