Paediatric Pathology Online
Pathology of Melanotic Neuroectodermal Tumour of Infancy
neuroectodermal tumour of infancy is a rare, rapidly expanding and
pigmented tumour in infancy.
(2) The first case was described in 1918 by Krompecher.
(3) In 1966 Borello and Gorlin first named the tumour as melanotic neuroectodermal tumour of infancy as the case they reported had high urinary excretion of vanillylmandelic acid (VMA) which suggested the tumour might be an origin of neural crest.
(4) These tumours commonly occur in the head and neck regions of children under the age of one.
(5) Melanotic neuroectodermal tumour of infancy is a nonulcerative, painless, and pigmented lesions, but the pigmentation cannot always be seen through the covering tissues.
(6) A broad nomenclature has been used for this tumour in the literature: Congenital melanocarcinoma, retinal anlage tumor, pigmented congenital epulis, melanotic progonoma, melanotic neuroectodermal tumor of infancy, pigmented ameloblastoma, pigmented teratoma, atypical melanoblastoma, melanotic adamantinoma, retinal choristoma, melanotic epithelial odontoma, and benign melanotic tumour.
(7) Melanotic neuroectodermal tumour of infancy generally occur in the maxilla (68%–80%), but they can occasionally arise in the skull (10.8%), mandible (5.8%) or brain (4.3%).
(8) In addition to the head and neck region, other sites can be affected by the lesion less frequently, including the femur, epididymis, ovaries, uterus and mediastinum.
(9) Melanotic neuroectodermal tumour of infancy is regarded as a benign tumour , although it can present as a locally aggressive tumour including gradual invasion of the surrounding bone and sinuses.
(10) This tumour is characterized by a high recurrence rate that varies between 10% and 60% and the risk of malignant transformation is 6.6%.
(11) Although several authors have reported positive results following surgical treatment and chemotherapy, other authors have found radiotherapy and chemotherapy to be ineffective in controlling melanotic neuroectodermal tumour of infancy.
(12) Serious adverse effects are generally associated with chemotherapy in young children, hence, chemotherapy should be avoided to prevent these adverse effects.
(13) Grossly, the tumours are usually firm, solid and well-defined with gray-black cut surface.
(14) These are biphasic tumors composed of small-cell and large-cell components that are arranged in nest or cord arrangements set in a vascularized fibrous stroma.
(15) The nests of small cells are usually surrounded by large cells that form structures resembling gland tissue.
(16) The large, cigar-shaped, elongated melanin granules that are commonly observed in melanotic neuroectodermal tumour of infancy differ from those observed in melanoma, in which the granules are smaller or are unpredictably sized inclusions in melanophages.
(17) The immunohistochemical profile of Melanotic neuroectodermal tumour of infancy is generally positive for cytokeratin and HMB45 and negative for S100 protein.
(18) The differential diagnosis for Melanotic neuroectodermal tumour of infancy includes metastatic neuroblastoma, rhabdomyosarcoma, Ewing’s sarcoma/peripheral primitive neuroectodermal tumor, desmoplastic round cell tumour, melanoma, and lymphoma.
Ma Y, Zheng J, Yang S, et al. Melanotic neuroectodermal tumor of infancy in the soft tissue of the forearm: report of a case. International Journal of Clinical and Experimental Pathology. 2015;8(10):13584-13589
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