Clinical spectrum of primary mediastinal tumors: A comparison of adult and pediatric populations at a single Japanese institution

Background and Objectives: The purpose of this study was to review our Japanese institutional experience of mediastinal tumors and to compare differences in the clinical spectrum between adults and children. Methods: We retrospectively reviewed the records of 806 patients (676 adults and 130 children) between 1951 and 2000 at our institution. Results: There were 244 thymomas (36%), 106 germ cell tumors (16%), 95 congenital cysts (14%), 82 lymphomas (12%), 76 neurogenic tumors (11%), and 24 thyroid tumors (4%) in adult patients. There were 60 neurogenic tumors (46%), 24 germ cell tumor (19%), 17 lymphoma (13%), 10 congenital cysts (8%), and 5 thymomas (4%) in the pediatric patients. There was a significant higher incidence of neurogenic tumors and a lower incidence of thymomas and thyroid tumors in children than adults. The most common location was the anterior compartment (68%) in adults and the posterior compartment in children (52%). The prevalence of malignancy in pediatric patients was lower than adults (37% vs. 47%; P < 0.05). Symptoms due to compression or direct invasion into adjacent structures may have caused the higher incidence of dyspnea or respiratory distress in the pediatric group compared to the adults (15.4% vs. 4.0%; P < 0.001). There were fewer incidences of facial edema in children compared to adults (2.6% vs. 10.7%; P < 0.02). Emergent operations were required more often in the pediatric group than the adult group. Conclusions: We demonstrated definite differences in histologic distribution, location, and symptomatology in mediastinal tumors between adult and pediatric populations, which should be considered in the evaluation and planning of a therapeutic modality for mediastinal tumors.