Per the Mayo Clinic, thrombocytosis is having too many red platelets. What I read says thrombocytopenia is too few. Conditions ending in penia I think refer to a lower amount of something, for example ostopenia in too little bone density. Maybe I am wrong and I am not familiar with Essential Thrombocytopenia, but it is contradictory to me. You write thrombocythemia. Oops just reread and I see spell diff and I do agree with you. It looks like others have misspelled the condition too. Thanks for clarifying.