Topics include: Rare Cancers; Mast Cell Leukemia; Uveal Melanoma; Esthesioneuroblastoma; Parathyroid Carcinoma; Thymoma/Thymic Carcinoma; Mesothelioma; Gastrointestinal Stromal Tumor (GIST); Uterine Sarcoma; Cancer of the Appendix; Urethral Cancer; Anal Cancer; and Merkel Cell Carcinoma.