Evaluation of 342 cases of mediastinal/thymic carcinoids collected from literature: a comparative study between typical carcinoids and atypical varieties.

This study is aimed to provide extensive and useful information based on an analysis of a large and reliable series of cases regarding mediastinal/thymic carcinoids, both typical and atypical. It also serves to assist investigators to improve their research activities in this particular field. In the present study, 342 patients (3.8%) with mediastinal/thymic carcinoids from amongst a total series of 8,970 patients with carcinoids, registered in the Niigata Registry for gut-pancreatic endocrinomas, were analyzed to clarify their detailed clinicopathological characteristics. Added to an analysis of mediastinal/thymic series including a comparison between typical and atypical carcinoid varieties, another comparative study was performed between the present series and a bronchopulmonary series. Mediastinal/thymic carcinoids may be briefly characterized by 1) no significant difference in major factors statistically demonstrable between typical carcinoids and atypical varieties, 2) a male preponderance, 3) difficult (delayed) preoperative diagnosis, 4) a high rate of metastasis, 5) a large tumor size on average (delayed detection), 6) a low rate of the carcinoid syndrome, 7) a high rate of association of the Cushing syndrome, and 8) low postoperative survival rates.