Biological characteristics of neuroblastoma with spontaneous tumor reduction: a case report

The authors examined the biological characteristics of a neuroblastoma with spontaneous tumor reduction. A 6-month-old boy with a pelvic neuroblastoma underwent surgical extirpation of the tumor 1 month after diagnosis. The size of the tumor reduced spontaneously while he was awaiting operation. The low proliferative activity of the tumor cells and the presence of apoptosis in the tumor tissue were shown by an immunohistochemical method using anti-PCNA antibody and a DNA fragmentation analysis, respectively. These results suggest that the spontaneous tumor reduction seen in this patient may well be caused by the overwhelming apoptosis of tumor cells.