Malignant melanoma of the sympathetic chain: with a consideration of pigmented nerve sheath tumours

Abstract
A case of malignant melanoma of the posterior mediastinum, arising from the sympathetic chain is reported. The structural features and the presence of long-spaced collagen on EM examination suggest schwannian derivation of the tumor. Similar tumors are reviewed and the histogenesis of pigmented nerve sheath tumors in general is discussed. The term malignant melanotic schwannoma is probably the most appropriate for the tumor entity described here.