myoma vs leiomyoma

myoma and leiomyoma both are nouns.

Word	Noun	Adjective	Verb	Adverb
myoma	Yes	No	No	No
leiomyoma	Yes	No	No	No

As nouns, leiomyoma is a hyponym of myoma; that is, leiomyoma is a word with a more specific, narrower meaning than myoma:

myoma: a benign tumor composed of muscle tissue
leiomyoma: benign tumor of smooth muscle (usually in the uterus or digestive tract)

Other hyponyms of myoma include rhabdomyoma.

myoma (noun)	leiomyoma (noun)
a benign tumor composed of muscle tissue	benign tumor of smooth muscle (usually in the uterus or digestive tract)