Thymoma associated with malignancies may herald a hereditary cancer syndrome.

Two probands with thymoma and other primary malignancies with multiple cancer patients in the family are described. Types of malignancies, pattern of pedigree and age of the patients do not match the known familial cancer syndromes. One proband was a very rare case with five discrete primary malignancies; TP53 sequencing and karyotyping did not reveal any mutations. These cases suggest thymoma associated malignancies may herald a hereditary cancer syndrome.