hystricismPath.|ˈhɪstrɪsɪz(ə)m| [ad.mod.L. hystricismus, f.hystrix porcupine.] The porcupine disease, an extreme form of ichthyosis (ichthyosis hystrix), in which the epidermis is covered with horny prominences. 1886in Syd. Soc.Lex.1891in F. P. Foster Med.Dict. 1960.