Diagnostic accuracy of reflectance confocal microscopy for lesions typified by dermoscopic island.
BACKGROUND
Dermoscopic island (DI) is a dermoscopic clue for the diagnosis of thin melanoma (MM). However, its positive predictive value is about 50% and several naevi with DI are unnecessarily excised. Reflectance confocal microscopy (RCM) is a second level non-invasive imaging tool that increases diagnostic accuracy for MM.


OBJECTIVE
To evaluate diagnostic RCM features of pigmented lesions typified by the presence of DI and calculate RCM diagnostic accuracy for MM diagnosis.


METHODS
All lesions with DI were retrieved from a database of 1964 cases. RCM diagnoses were given without being aware of the histopathological diagnoses. The number of MMs among lesions presenting with DI and the sensitivity and specificity of RCM for MM were assessed. The frequencies of dermoscopic and RCM features were calculated to evaluate significant differences in naevi and MMs showing DI (Chi-square test). Independently significant RCM criteria for MM were identified by discriminant analysis.


RESULTS
Sixty-three (3.2%) out of 1964 lesions presented DI. Among them, 30.2% were in situ MMs and 12.7% invasive MMs. Sensitivity and specificity of RCM for the diagnosis of MM in case of DI was 88.9%. Pagetoid cells (Wilks' lambda .804, P < 0.001) and atypical cells at dermo-epidermal junction (Wilks' lambda .762, P < 0.001) were identified to differentiate MM from naevi.


CONCLUSIONS
Our study confirmed that DI could be a sign of early MMs and underlined that RCM could be a good tool to discriminate MMs and naevi in the presence of DI because it can identify the presence of cytological atypia.
Department of Dermatology, Faculty of Medicine, University Hospital Complex, Santiago de Compostela, Spain.
O
O
Figueroa-Silva
Department of Dermatology, University Hospital of Saint Etienne, Saint Etienne, France.
E
E
Cinotti
Department of Dermatology, Regional Hospital of Asa Norte, Brasilia, Brazil.
T
T
de Almeida Silva
Skin Cancer Unit, Arcispedale S. Maria Nuova, IRCCS, Reggio Emilia, Italy.
E
E
Moscarella
Skin Cancer Unit, Arcispedale S. Maria Nuova, IRCCS, Reggio Emilia, Italy.
A
A
Lallas
Department of Dermatology, University of Modena and Reggio Emilia, Modena, Italy.
S
S
Ciardo
Skin Cancer Unit, Arcispedale S. Maria Nuova, IRCCS, Reggio Emilia, Italy.
G
G
Argenziano
Department of Dermatology, University of Modena and Reggio Emilia, Modena, Italy.
G
G
Pellacani
Pathology Unit, Arcispedale S. Maria Nuova, IRCCS, Reggio Emilia, Italy.
S
S
Piana
Skin Cancer Unit, Arcispedale S. Maria Nuova, IRCCS, Reggio Emilia, Italy.
C
C
Longo
D001706:Biopsy; D046169:Dermoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D008545:Melanoma / Q000175:diagnosis* / Q000473:pathology; D018613:Microscopy, Confocal / Q000379:methods*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000473:pathology