Neuroblastoma in situ.

Two cases of neuroblastoma in situ incidentally found in young infants at autopsy are reported. One was an 8-day-old female infant of large for dates clinically diagnosed as fetal erythroblastosis. Histologically, several foci of tumor were scattered within the medulla of the left adrenal gland. This case was thought to be multiple neuroblastoma in situ. The other was a 34-day-old male infant who was born premature and associated with patent ductus arteriosus (PDA). Grossly, a solitary small nodule was seen in the right adrenal gland. Microscopically, the lesion was located within the medulla. In both cases, the tumor was composed of lymphocyte-like small and dark cells with rosette formations. Local infiltrations were observed, but not metastasis. The review of 611 autopsy cases of neuroblastoma reported in the Annual of the Pathological Autopsy Cases in Japan, vol. 11 (1968) to vol. 20 (1977)2 revealed 7 cases of neuroblastoma in situ including one of our cases. The peculiar features of neuroblastoma were described.