Melanotic schwannoma arising in the sympathetic ganglion

A case of melanotic schwannoma, the 28th reported in the literature and the second to arise in the sympathetic ganglion, was reported in a 39-year-old man who remains free of recurrence or metastasis since removal of the tumor. In common with earlier benign melanotic schwannomas, its ultrastructural study revealed well-developed contiguous external lamina as opposed to absent or only minimally developed external lamina seen in malignant melanotic schwannomas. This emphasizes the use of electron microscopy in the diagnosis of this tumor. The literature yields only nine melanotic tumors (including one malignant melanotic schwannoma) arising in the sympathetic nervous system; all nine tumors had a malignant clinical course. Therefore, the present case represents the first "benign" tumor among ten melanotic tumors, and the second among 28 melanotic schwannomas to arise in the sympathetic nervous system.