GUARDIANES DE LOS CRISTALES. CINCO REINOSdoi:10.1163/22134417-90000060lactoferrinpolymorphismaggressive periodontitisAfrican AmericanThymomas are low-grade epithelial cancers of the thymus whose prevalence varies between 0.1/100,000 and 0.4/100,000. Familial occurrence of thymoma is very rare. We studied ...