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

Abstract

PurposeTo investigate the clinicopathological features and BRAF V600E mutation of melanotic neuroectodermal tumor of infancy (MNTI).Materials and MethodsEleven 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.ResultsOf 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.ConclusionMNTI, 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 mandible

“…More than 500 cases of MNTI have been reported worldwide by Rachidi et al In addition to the 472 cases reported between 1918 and 2013 as a part of the largest retrospective study, [5] we found 49 cases reported between January 2014 and June 2021 by searching PubMed [3,4,9–32,36–38] . In a systematic review of 472 MNTI cases, [5] most cases developed within 1 year of age, with more than 90% of cases occurring in the craniofacial region, such as the maxilla (60.3%), skull (18.1%), and mandible (10.3%).…”

“…More than 500 cases of MNTI have been reported worldwide by Rachidi et al In addition to the 472 cases reported between 1918 and 2013 as a part of the largest retrospective study, [ 5 ] we found 49 cases reported between January 2014 and June 2021 by searching PubMed. [ 3 , 4 , 9 – 32 , 36 – 38 ] In a systematic review of 472 MNTI cases, [ 5 ] most cases developed within 1 year of age, with more than 90% of cases occurring in the craniofacial region, such as the maxilla (60.3%), skull (18.1%), and mandible (10.3%). On the other hand, to summarize the reported cases since 2014, 27 (87.1%) cases of MNTI developed within 1 year of age, and 32 (65.3%) cases occurred in the maxilla, 4 (8.2%) in the mandible, and 1 (2%) in the hard palate, while 12 (24.5%) cases occurred outside the oral cavity, such as the cranial bone, middle ear, upper arm, fibula, and ovary.…”

Melanotic Neuroectodermal Tumor of Infancy in the Epididymis: A Case Report

“…The result is that our case did not harbor BRAFV600E mutation, which is consistent with another study. 17 In addition, Barnes et al reported, in 2016, that a germline mutation of CDKN2A and a novel RPLP1:: C19MC fusion was detected in MNTI. 18 Further research is needed to get a better understanding of molecular biology and warranted to improve the efficiency of current treatment strategies.…”