nephrolithiasis vs renal lithiasis

nephrolithiasis and renal lithiasis both are nouns.

Word	Noun	Adjective	Verb	Adverb
nephrolithiasis	Yes	No	No	No
renal lithiasis	Yes	No	No	No

As nouns, nephrolithiasis and renal lithiasis are synonyms defined as:

nephrolithiasis and renal lithiasis: the presence of kidney stones (calculi) in the kidney

nephrolithiasis (noun)	renal lithiasis (noun)
the presence of kidney stones (calculi) in the kidney	the presence of kidney stones (calculi) in the kidney