title: Undifferentiated carcinoma of the thyroid: case reports and review of the Puerto Rico Cancer Registry experience from 1970--1974.
mesh_terms: D000368:Aged; D005260:Female; D006258:Head and Neck Neoplasms / Q000453:epidemiology* / Q000648:ultrastructure*; D006801:Humans; D008875:Middle Aged; D011647:Puerto Rico; D012042:Registries; D013964:Thyroid Neoplasms / Q000453:epidemiology* / Q000648:ultrastructure