spore sac vs spore case

spore sac and spore case both are nouns.

Word	Noun	Adjective	Verb	Adverb
spore sac	Yes	No	No	No
spore case	Yes	No	No	No

As nouns, spore sac and spore case are synonyms defined as:

Other synonyms of spore sac include sporangium.

spore sac (noun)	spore case (noun)
organ containing or producing spores	organ containing or producing spores
	specialized leaf branch in certain aquatic ferns that encloses the sori or clusters of sporangia