Correct spelling for the English word "spleneolus" is [splˌɛnɪˈə͡ʊləs], [splˌɛnɪˈəʊləs], [s_p_l_ˌɛ_n_ɪ__ˈəʊ_l_ə_s] (IPA phonetic alphabet).
Accessory spleen, lien accessorius.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.