An atypical nevus is a single lesion with irregular features, whereas a nevus spilus is a background café-au-lait patch with multiple, smaller, regular dark spots within it.
A simple café-au-lait macule is uniformly light brown, lacking the superimposed darker speckles that define a nevus spilus.
A large CMN can have variations in color, but it doesn't typically have the distinct "speckled" on a lighter background appearance of a nevus spilus.
A junctional nevus is a single, discrete macule, not a large patch with multiple smaller macules inside it.
A lentigo is a single freckle-like spot; multiple lentigines can occur, but a nevus spilus is specifically defined by their appearance on a background hyperpigmented patch.
A pigmented BCC is a malignancy with features like a pearly border, a different entity than a benign nevus spilus.
