Level 3: Intradermal nevi
Intradermal nevi (IDN) are first and foremost defined by their clinical morphology as either raised dome shaped lesions or as sessile mamillated lesions. IDN with this clinical morphology will usually reveal one or more of the following features: comma vessels, brown halo, globules, small foci of tan structureless pigmentation, hypopigmented areas. They can also reveal arborizing vessels making it difficult to differentiate them from BCC. The clues to the diagnosis of IDN include the presence of the aforementioned features and lack of other BCC-specific features. In addition, the arborizing vessels in IDN are often a tad out of focus and have a bluish hue. In contrast, in BCC the arborizing vessels are usually sharply in focus and bright red in color.
