papillary tumor vs papillary tumour

papillary tumor and papillary tumour both are nouns.

Word	Noun	Adjective	Verb	Adverb
papillary tumor	Yes	No	No	No
papillary tumour	Yes	No	No	No

As nouns, papillary tumor and papillary tumour are synonyms defined as:

papillary tumor and papillary tumour: a benign epithelial tumor forming a rounded mass

Other synonyms of papillary tumor include papilloma, villoma.

papillary tumor (noun)	papillary tumour (noun)
a benign epithelial tumor forming a rounded mass	a benign epithelial tumor forming a rounded mass