pheochromocytoma vs tumor

pheochromocytoma and tumor both are nouns.

Word	Noun	Adjective	Verb	Adverb
pheochromocytoma	Yes	No	No	No
tumor	Yes	No	No	No

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

pheochromocytoma: a vascular tumor of the adrenal gland; hypersecretion of epinephrine results in intermittent or sustained hypertension
tumor: an abnormal new mass of tissue that serves no purpose

Other hypernyms of pheochromocytoma include neoplasm, tumour.

pheochromocytoma (noun)	tumor (noun)
a vascular tumor of the adrenal gland; hypersecretion of epinephrine results in intermittent or sustained hypertension	an abnormal new mass of tissue that serves no purpose