Interobserver agreement on dermoscopic features of pigmented basal cell carcinoma.

Background: A dermoscopic method based on the absence of a pigment network and the presence of at least one of six positive features has been described for diagnosis of pigmented basal cell carcinoma (BCC).

Objective: To evaluate the observers' global agreement and interobserver agreement on each dermoscopic parameter of the method recently proposed.

Methods: Dermoscopic images of 56 pigmented BCCs were examined by five observers with different degrees of experience in dermoscopy.

Results: An overall full agreement was reached for the absence of pigment network (k = 1). Very good agreement was detected for the presence of spoke wheel areas (k = 0.85) and arborizing vessels (k = 0.72), and good agreement was shown for ulceration (k = 0.49) and multiple blue-gray globules (k = 0.41). No agreement was identified on large blue-gray ovoid nests (k = 0.28) and leaflike areas (k = 0.26).

Conclusions: We confirm the reproducibility of the method and show that ulceration, spoke wheel areas, and arborizing tel- angiectases represent the most robust positive parameters.