Melanotic Neuroectodermal Tumor of the Skull and Meninges in Infancy

Abstract

Three cases of melanotic neuroectodermal tumors of infancy are presented. Two were localized on the midline, involving the skull and extending subdurally. One was located on the inner aspect of the dura and developed intracranially. Two had a benign course following gross total removal. One had a malignant course, recurring locally and spreading within the brain. The difficulties of removing these tumors when they are implanted on the midline are stressed. Histological features of prognostic value are pointed out. Further support for neural crest origin of these tumors is given.

Melanotic Neuroectodermal Tumor of Infancy

“…6 Some authors advocated the necessity of post-operative chemotherapy to prevent distant metastasis and aggressiveness that was estimated less than 5%. 7 The tumor appears as a sessile or slightly pedunculated, lobulated, firm mass typically deep blue or with a dark discoloured surface. It is usually 2-4cm in diameter but may show a huge involvement showing a well defined or a poorly defined destructive radiolucency of the bone with a "sunburst" appearance as mild calcification along vessels radiating from the centre of the tumor.…”

Benign Melanocytic Tumor in Infancy: Discussion on a Rare Case and Review of the Literature

“…These tumors are believed to develop from leptomeningeal melanocytes, and they closely resemble the other melanocytic neoplasms of the CNS. Differential diagnosis includes the pigmented meningioma, melanotic schwannoma, primary or secondary malignant melanoma and MNTI [5, 11, 13, 14, 17, 19, 20, 21, 22, 23]. The common derivation of the respective cells of these tumors from neural crest precursors may result in difficulties in distinguishing them.…”

“…There have been only 5 patients under 20, and none younger than 9 years of age in the literature [18, 19, 31, 41]. By contrast, MNTI usually manifest themselves in the earlier stages of life [22]. …”

“…On the other hand, epithelial membrane antigen is an important prognostic marker for meningiomas, while Leu 7 is for schwannomas [44]. MNTI tend to show strong reactivity to neuron-specific enolase, vimentin and S-100 protein [22]. Ultrastructural studies may have a prognostic value in extreme variants of melanotic CNS tumors.…”

“…These findings are nonspecific and similar to that of meningiomas, schwannomas and MNTI. The typical radiological findings of MNTI are the sclerosis and hyperostosis of the involved segment, as the evidence of abundant osteoblastic activity, and the significant contrast enhancement of the lesion in the computerized tomography and MRI [22]. On the other hand, midline localization excludes a possible diagnosis of schwannoma since these tumors are in close vicinity to cranial or spinal foramina.…”