noun which may take the genitive case particle 'no', noun
mottled; patchy; macular; porphyritic
Technical term used in geology, medicine, and biology to describe irregular spotted or patchy patterns. 斑状 is a noun that often modifies another noun with の, as in 斑状の模様 (mottled pattern).
この岩石は斑状の組織を示している。
This rock shows a porphyritic texture.
皮膚に斑状の発疹が現れた。
A macular rash appeared on the skin.