Melanotic neuroectodermal tumour of infancy is an uncommon pigmented neoplasm of neural crest origin. It was first described in 1918 by Krompecher, known as congenital melanocarcinoma at that time. Although it is generally agreed upon that it is a benign entity, it is locally aggressive and has a significant recurrent risk, reported to be between 10-15%. There have also been prior reports of malignant behaviour in these tumours, although extremely rare. The majority of cases of this tumour (about 70%) arise from the maxilla and its occurrence in the cranial vault represents approximately 15.6% of cases. We describe a rare case of melanotic neuroectodermal tumour of infancy, with simultaneous involvement of the cranial vault and petrous temporal bone, in a four-month-old child, complicated by post-surgical pseudo-meningocele. This case illustrates the diagnostic dilemma in differentiating reactive osseous sclerosis from direct tumour infiltration, both of which can occur in the context of melanotic neuroectodermal tumour of infancy. The discussion places emphasis on differential diagnoses and useful radiological features to assist in clinching the diagnosis of melanotic neuroectodermal tumour of infancy.
Keywords: Melanotic neuroectodermal tumour of infancy; cranial vault mass; pigmented neoplasm; pseudo-meningocele.