Surface microscopy of pigmented basal cell carcinoma

Objectives: To describe the relevant morphologic features and to create a s imple diagnostic method for pigmented basal cell carcinoma (BCC) using in v ivo cutaneous surface microscopy (ie, dermoscopy, dermatoscopy, or oil epil uminescence microscopy). Design: Pigmented skin lesions were photographed in vivo using immersion oi l (surface microscopy). All pigmented skin lesions were excised and reviewe d for histological diagnosis. Photographs of 142 pigmented BCCs, 142 invasi ve melanomas, and 142 benign pigmented skin lesions were randomly divided i nto 2 equally sized training and test sets. Images from the training set we re scored for 45 surface microscopy features. From this a model was derived and tested on the independent test set. Setting: All patients were recruited from the primary case and referral cen ters of the Sydney Melanoma Unit, Sydney, Australia, and the Skin and Cance r Unit, Skin and Cancer Associates, Plantation, Fla. Patients: A random sample (selected from a larger database) of patients who se lesions were excised. Main Outcome Measures: Sensitivity and specificity of the model for diagnos is of pigmented BCCs. Results: The following model was created. For a pigmented BCC to be diagnos ed it must not have the negative feature of a pigment network and must have 1 or more of the following 6 positive features: large gray-blue ovoid nest s, multiple gray-blue globules, maple leaflike areas, spoke wheel areas, ul ceration, and arborizing "treelike" telangiectasia. On an independent test set the model had a sensitivity of 97% for the diagnosis of pigmented BCCs and a specificity of 93% for the invasive melanoma set and 92% for the beni gn pigmented skin lesion set. Conclusion: A robust surface microscopy method is described that allows the diagnosis of pigmented BCCs from invasive melanomas and benign pigmented s kin lesions.