Melanotic tumours (blue naevi) of spinal nerve roots

Abstract

Four cases interpreted as intraspinal blue naevi are reported. The patients were adults females with an age range between 22 and 60 yr. In three there was a single tumour arising from the cervical posterior nerve roots and in the fourth there were multiple tumours arising from the posterior nerve roots of the spinal cord and occurring within the cerebello--pontine angle. The histological appearances of the tumours were similar in every way to those of dermal blue naevi. One was of the more common spindle-celled type and three of the cellular variant. The tumours contained melanin-pigment, and spindle cells with dendritic bipolar processes of the type described in dermal blue naevi. One was of the more common spindle-celled type and three of the cellular variant. The tumours contained melanin pigment, and spindle cells with dendritic bipolar processes of the type described in dermal blue naevi. Definite evidence of malignant tranformation was found in two cases and in a third, the appearances were suggestive for early malignant change. Therefore, unlike their dermal equivalents, intraspinal blue naevi appear to have a greater propensity for malignant transformation. In each case a careful clinical examination failed to reveal any evidence of a primary malignant melanoma. In the one case who died and on whom necropsy was performed, the failure to identify a primary cutaneous, mucosal or ocular melanoma substantiated our contention that these tumours were primary.

The ultra‐structure of a melanotic schwannoma of the skin

“…The relationship of the foregoing skin tumour and similar tumours such as those described by Bird and Willis to the cellular blue naevus remains obscure but similarity in location and morphology undoubtedly exist (Graham et al, 1976), suggesting that these tumours may also be closely related. Experimental evidence also exists which links the cellular blue naevus with the pigmented neurofibroma (Nakai and Rappaport, 1963).…”

Meningeal melanocytoma

“…There was increased cellularity, considerable increase of melanin pigment in both tumour cells and macrophages, and a slight increase in both cellular pleomorphism and mitotic figures (Fig. In a number of cases, however, these turnouts grossly and histologically resembling meningiomas, have been shown to lack the ultrastructural features of meningiomas or schwannomas, but share many morphological characteristics with melanocytic tumours of the dermis and uveal tract (cellular blue naevi, spindle A uveal melanoma) 8' 10, 15,18,21,41 These neoplasms, recently classified as "meningeal melanocytoma,,21, 41, represent a small group of pigmented extra-axial mass lesions with distinct clinical and pathological features. The tumour tissue was well delineated from the adjacent cerebellar cortex by an arachnoid lining containing a large number of melanin-pigment laden cells (Fig.…”

“…Within the spinal canal (9 cases), the tumours occur at any level, with intradural localization often attached to or arising from spinal roots, but can also arise in both the intradural and extradural compartements (cases 11,13,15). In 7 patients, the neoplasm arose as solitary mass intracranially, in the posterior fossa adjacent to the pons or cerebellum (5 cases) or within Meckel's cave (2 cases); some were attached to the trigeminal nerve (cases 1 and 6), others to the tentorium (cases 5 and 7).…”

Perineural Pattern of Aggregation of Cellular Blue Nevus: Probable Histoarchitectural Reminiscence of Histogenesis

“…1 Masson's histogenetic model was later reproposed, based on similar and equally suggestive observations of nerve and nerve-like structures, 2-8 and it was reinforced by a few, noteworthy reports on cellular blue nevi of the spinal roots and major nerve branches. 11,12 This model, however, is no longer quoted in the literature, and the finding of nerve structures within cellular blue nevi is considered of little significance. Moreover, the presence of nevus cells inside the endoneurium is considered analogous to the colonization of loco-regional lymph nodes, a well-known behavior of the cells of blue nevi, even when these are benign and do not show any sign of atypia.…”