before vowels sarc-, word-forming element in science meaning "flesh, fleshy, of the flesh;" from Latinized form of Greek sark-, combining form of sarx "flesh," traditionally derived from a PIE root *twerk-, *tuerk- "to cut" (source also of Avestan thwares "to cut"), but Beekes is dubious.
word-forming element meaning "like, like that of, thing like a ______," from Latinized form of Greek -oeidēs (three syllables), from eidos "form," related to idein "to see," eidenai "to know;" literally "to see" (from PIE *weid-es-, from root *weid- "to see"). The -o- is connective or a stem vowel from the previous element. Often implying an incomplete or imperfect resemblance to the thing indicated.
<a href="https://www.etymonline.com/word/sarcoid">Etymology of sarcoid by etymonline</a>
Harper, D. (n.d.). Etymology of sarcoid. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/sarcoid