Spinal melanotic schwannoma: a tumour with poor prognosis

Aim: To clarify the prognosis of melanotic schwannoma. This is a rare tumou r which is generally considered as a benign lesion, reported in many cases with a short follow-up only. Methods and results: Five cases of spinal melanotic schwannoma were retrosp ectively studied. The tumours were examined using standard histological, im munohistochemical and ultrastructural methods. No features of malignancy (h igh mitotic count, atypia or necrosis) were found in the primary tumours. T he follow-up period ranged from 3 to 7 years. Malignant clinical behaviour was clear-cut in four cases: three patients died from metastases to various sites and one presented several discrete spinal tumours of the same type s even years after the first operation. Only one patient presented no recurre nce and was free of disease 6 years after initial diagnosis. The review of 57 cases of the literature (including our cases), showed that 15% of the ca ses had recurrences and 26.3% were complicated by metastasis. Only 53% of t he cases followed for more than 5 years, were free of disease vs. 67.5% of the cases with shorter follow-up. Twenty additional cases had no follow-up. Conclusion: Appropriate long-term follow-up is required for all melanotic s chwannomas, as it may recur or metastasize after more than 5 years, even in the absence of overt malignant histological features.