Maturation of mass-screened localized adrenal neuroblastoma

Background/Purpose: In infants, neuroblastoma has been known to spontaneous ly differentiate into a benign ganglioneuroma. Although several investigato rs have compared mass-screened with unscreened, disseminated with localized , and adrenal with retroperitoneal neuroblastoma, there are very few cross- comparisons of the above parameters. Herein, the authors report the maturat ion of mass-screened, localized adrenal neuroblastoma. Methods: Fifty-one mass-screened adrenal neuroblastomas were divided into 2 groups, In infants less than 1 year of age (Group A), 45 neuroblastomas we re resected, whereas 6 neuroblastomas were resected after observation in 1- to 4-year-old children (group B). Histopathology of the tumors in the 2 gr oups was compared. Data were analyzed by chi (2) test, and P <.05 was consi dered significant. Results: According to the International Neuroblastoma Pathological Classifi cation, 41 of 45 tumors of group A were "differentiating neuroblastoma" and 4 of 6 tumors of group B were "maturing ganglioneuroma." Maturation toward ganglioneuroblastoma was observed in 16 neuroblastomas of group A (36%) an d 6 neuroblastomas of group B (100%). In group A, 58% had low mitosis karyo rrhexis index (MKI); all patients in group B had low MKI. Conclusions: If left untreated, maturation of mass-screened, localized adre nal neuroblastomas is a common phenomenon. These children do not need to un dergo early operation. J Pediatr Surg 36.1633-1636. Copyright (C) 2001 by W .B. Saunders Company.