essential anemia

es·sen·tial a·ne·mi·a

obsolete term for pernicious anemia; also used formerly for any type of anemia of unknown mechanism.

primary anaemia

(1) Anaemia as a primary condition, a now-dated concept given that all anaemias are “secondary” to a deficiency or excess—e.g., iron deficiency, haemogolinopathy, toxins, etc.
(2) Pernicious anaemia.