The records of 207 neuroblastoma patients seen at the Children's Hospital of Philadelphia between 1944 and 1977 were reviewed to study some of the features associated with the unusually good prognosis found in patients with Stage IV-S neuroblastoma. Initially, 22 patients appeared to fit the criteria of small primary tumor and distant disease in liver, skin, and/or marrow without evidence of bone metastases; 5 patients were subsequently rejected as being incorrectly staged. The remaining 17 patients had abdominal primary tumors and hepatic disease; in 12 of the 17, an enlarged liver was the presenting sign. Six patients had skin lesions, 4 had disease in the marrow on routine smear, and additional sites of spread were pancreas and bowel serosa. The treatment given was not systematic, and it was not possible to correlate any specific form of therapy with a satisfactory outcome. Eleven of 17 patients survived; 6 of 11 survivors had spontaneous regression of all or part of their disease, 5 of 6 who died received irradiation, chemotherapy, or both. Death usually occurred in the first month as a complication of the local disease; 1 patient succumbed to radiation nephritis. This study establishes that the special pattern of widespread neuroblastoma termed Stage IV-S does exist, and that it is associated with a good prognosis. Careful consideration should be given before selecting treatment for the Stage IV-S child because spontaneous regression is likely to occur in most of them. In patients with rapidly enlarging livers, renal or pulmonary complications may develop because of liver bulk or coagulopathies. Treatment should be directed to the liver in these cases because distant metastases seldom supervene. Low-dose irradiation, mild chemotherapy, and possibly surgical release of intraabdominal pressure using a silastic patch have all been effective. Unfortunately, patients occasionally succumb to local disease in spite of these and more aggressive measures.