Table 13. . Barcelona algorithm: a two-step method for the diagnosis of melanoma by reflectance confocal microscopy.

Step	Description	Features
Step 1.	Determine if the lesion is melanocytic or nonmelanocytic	Features of a melanocytic lesion: 1. Cobblestone pattern 2. Pagetoid spread 3. Mesh appearance at DEJ 4. Presence of dermal clusters of cells or dermal nests
Step 2.	Determine if the lesion is a nevus or a melanoma	Protective features (i.e., associated with nevi; -1 point per feature) 1. Typical basal cells 2. Edged papillae Risk features (i.e., associated with melanoma; +1 point per feature) 2. Roundish pagetoid cells 3. Atypical nucleated cells in the dermis

DEJ: Dermoepidermal junction.