benign tumor vs neoplasm

benign tumor and neoplasm both are nouns.

Word	Noun	Adjective	Verb	Adverb
benign tumor	Yes	No	No	No
neoplasm	Yes	No	No	No

As nouns, neoplasm is a hypernym of benign tumor; that is, neoplasm is a word with a broader meaning than benign tumor:

Other hypernyms of benign tumor include tumor, tumour.

benign tumor (noun)	neoplasm (noun)
a tumor that is not cancerous	an abnormal new mass of tissue that serves no purpose