ADULT GANGLIONEUROBLASTOMA OF THE ANTERIOR MEDIASTINUM

A case of gan,ganglioneuroblastoma occurring in the anterior mediastin um of a 79 year-old man is reported. The tumor was mainly composed of neuroblasts with occasional ganglion cells. Foci of melanin-laden cell s were also identified. Immunohistochemistry revealed that the tumor c ells showed both schwannian and melanocytic differentiation with immun oreactivity to anti-S100 protein and anti-HMB45 antibodies. In additio n, the tumor contained several microcysts lined by squamous epithelial and one lymphoid tissue abundant in T lymphocytes, which appeared to be derived from thymic tissue. This case is unique in that neuroblasto ma group tumors including ganglioneuroblastoma is uncommon in the elde rly and in the thymic region, and rarely shows melanocytic differentia tion. To the best of our knowledge, this case is a tumor of neuroblast oma group occuring in the eldest patient.