| Global features | ||
| Pattern | Pigment distribution/variant | Diagnostic associations |
| Reticular pattern |
| Acquired melanocytic nevus or congenital melanocytic nevus |
| Globular pattern | Cobblestone pattern | The cobblestone pattern is usually associated with congenital melanocytic nevi. The noncobblestone globular pattern can be seen in acquired nevi and in Spitz nevi. |
| Homogeneous pattern | Gray-blue | Blue nevus |
| Brown | Usually congenital melanocytic nevi | |
| Tan-pink | Nevi in fair skin | |
| Starburst pattern | Peripheral globules that are in a tiered distribution | Spitz/Reed nevus |
| Two component pattern | Acquired of congenital melanocytic nevi | |
| Multicomponent pattern | Melanoma Congenital nevi or acquired dysplastic nevi | |
| Parallel pattern | Nevi on volar skin Melanoma | |
| Nonspecific pattern | Melanoma should enter the differential diagnosis | |
| Local features | ||
| Criteria | Variants | Diagnostic associations |
| Pigment network | Typical Light to dark-brown network displaying minimal variation in line color and thickness. In addition, there is minimal variation in the size of the holes in the network. | Benign melanocytic lesion |
| Atypical Increased variability in the width of the network lines, their color and distribution. Line color with gray hues are also considered atypical. The holes sizes also have increased variability. May end abruptly at the periphery.[6] | Dysplastic nevi Melanoma/Spitz | |
| Negative network | Regular Symmetrically located within the lesion. | Congenital melanocytic nevi, Spitz nevi, melanoma |
| Irregular Diffuse throughout the lesion or focally located. | Melanoma/Spitz | |
| Dots | Regular Associated with a regular network and appear situated on top of the pigmented network, in the holes of the network, or in the center of an otherwise reticular pattern nevus. | Benign melanocytic lesion |
| Irregular Associated with an atypical network or no network at all and located at the periphery of the lesion. | Melanoma/Spitz | |
| Globules | Regular Multiple globules displaying minimal variation in globule size and color distributed in an organized manner within the lesion or symmetrically located in the center or around the entire periphery. | Benign melanocytic lesion |
| Irregular Multiple globules of different size, shape, and color. Asymmetrically and/or focally distributed within the lesion. | Melanoma/Spitz[7] | |
| Streaks (pseudopods and radial streaming) | Regular Radial projections at the periphery of the lesion, distributed around the entire perimeter of the lesion, extending from the tumor toward the surrounding normal skin.[8] | Spitz/Reed nevus |
| Irregular Radial projections at the periphery of the lesion; irregularly, asymmetric and focally distributed.[8] | Melanoma/Spitz | |
| Blue-white veil over raised areas | Regular Tend to be centrally located or homogeneous throughout the lesion. | Blue nevi/Spitz |
| Irregular Tend to be asymmetrically located or diffuse throughout the lesion, but with different hues. | Melanoma | |
| Regression structures (consists of granularity and scar-like areas. When both are present together, it gives the appearance of a blue-white veil over macular areas)[9] | Regular Tend to be symmetrically located and involve less than 10 percent of the surface area of the lesion. | Nevus |
| Irregular Tend to be asymmetrically located and often involve more than 50 percent of the lesion. | Melanoma | |
| Hypopigmented areas (structureless/homogeneous) | Regular Centrally located with peripheral network. | Nevus |
| Irregular Structureless, light brown area, located at the periphery of the lesion, larger than 10 percent of a lesion's surface area[10]. | Melanoma | |
| Blotch | Regular One blotch located in the center of an otherwise benign, reticular nevus. | Acquired melanocytic nevus |
| Irregular More than one blotch or a blotch that is asymmetrically and/or focally located at the periphery. Eccentric peripheral hyperpigmentation is often found in melanoma.[4] | Melanoma | |
| Vascular structures* | Regular Comma vessels. | Dermal nevi Congenital melanocytic nevi[11] |
| Irregular Serpentine (linear irregular) vessels. Polymorphous vessels. Corkscrew vessels: usually seen in nodular melanoma, desmoplastic melanoma or melanoma metastases. | Melanoma/Spitz Dysplastic or Clark nevus[11,12] | |
| Crystalline structures (also known as shiny, white streaks) | Melanoma[13,14] Spitz nevi[13,14] | |
