Role of dermatoscope in diagnosing and differentiating different types of seborrheic keratoses

Abstract

Background Seborrheic keratosis (SK) is the most common benign skin tumour to be misdiagnosed clinically as melanoma. SK may grow rapidly, is dark coloured with black areas and is accompanied with itching. Thus, it is difficult to distinguish it from malignant melanoma on clinical basis. Dermatoscope is a simple noninvasive tool useful for the early recognition of pigmented skin tumours, especially SK, melanoma and pigmented basal cell carcinoma, as it helps in differentiating each of them by specific criteria. In case a doubt about the diagnosis persists, biopsy is carried out for confirmation. Aim of the work The aim of the present study was to determine the role of dermatoscope in diagnosing and differentiating different types of SK, and its ability to detect suspicious lesions and confirm diagnosis by using histopathology. Patients and methods This study was carried out on 50 SK patients; out of them nine had suspicious lesions. All patients were subjected to dermatological, dermoscopic and histopathological examinations for suspicious lesions. Results In our study, the most common dermoscopic findings for different types of SK (stucco, dermatosis papulosa nigra, melanoacanthoma, flat type) were sharp demarcated border, comedo-like openings, milia-like cysts, moth-eaten borders and cribriform pattern. In addition, hairpin blood vessels and fat finger appeared in flat type SK. In our study, the dermoscopic criteria of suspicious lesions (n = 9, 18%) was diagnostic by 22.2% to tumour, as it showed structureless area and blue gray clods (n = 1, 11.1%); structureless area, yellow clods and blue gray clods (n = 1, 11.1%); and sharp demarcated borders, comedo-like openings, moth-eaten borders, milia-like cysts and fissures and ridges (n = 7, 77.8%). Overall, 22.2% of the biopsied cases were basal cell carcinoma and 77.8% were SK. Conclusion SK must be taken seriously with close follow-up by using dermoscopy to detect any malignant changes.