Neuroblastoma: incomplete differentiation on the way to maturation or morphological alteration resembling maturity?

The following study was performed to investigate whether antitumor agents can induce maturation of advanced neuroblastoma (NB). Of 56 NB patients (1970-1987), 13 in stage III or IV underwent resection of the primary tumor (11 abdominal, 2 mediastinal) following complete or partial response to preoperative chemotherapy (11 conventional cytotoxic chemotherapy, 2 conventional cytotoxic chemotherapy combined with intraarterial infusion of prostaglandin E1 and oral papaverine). Histological examinations, performed on these 13 NB patients before and after chemotherapy, showed (1) differentiation of the NB to ganglioneuroblastoma (GNB) with predominance of mature atypical ganglion cells, development of stromal components and a few immature malignant cells in 10 of 13 and (2) differentiation of the NB to a more mature form than was seen histologically before treatment in the remaining 3. Our results indicate that the morphological differentiation of immature NB in advanced stage to more mature GNB can be induced by conventional cytotoxic chemotherapy with or without so-called 'maturation-inducing' agents. However, the chemotherapy-induced morphological differentiation did not correlate with the prognosis of the patients.