Dermoscopic features and differential diagnosis of sebaceous carcinoma.

Sebaceous carcinoma is a rare malignant skin neoplasm arising from sebaceous glands. Its clinical diagnosis is difficult and reports of dermoscopic findings have been limited. This study aims to analyze its dermoscopic features and differential diagnosis in dermoscopic examination. The study included patients diagnosed with histologically proven sebaceous carcinomas as well as diagnosed cases of sebaceous hyperplasia, sebaceoma, squamous cell carcinoma and basal cell carcinoma for comparison of dermoscopic findings. The dermoscopic criterion of presence of sebaceous carcinoma was scored only if the two evaluators reached a consensus. Fifteen cases of histologically diagnosed sebaceous carcinoma were included in our study. All cases were extraocular sebaceous carcinoma. A total of 60 (15 basal cell carcinomas, 15 squamous cell carcinomas, 15 sebaceous hyperplasias and 15 sebaceomas) cases were collected for comparing dermoscopic features with sebaceous carcinoma. In dermoscopic analysis of sebaceous carcinoma, the majority of tumors (66.67%) presented polymorphic vessel pattern. Other features included whitish-pink areas (80%), yellowish structures (73.33%) and yellowish structureless areas (60%). Yellowish structures in sebaceous carcinomas are the main dermoscopic findings to differentiate squamous cell and basal cell carcinomas (P < 0.001), whereas purplish globules, shiny white blotches and strands and whitish-pink area distinguish sebaceous carcinomas from other sebaceous tumors (P < 0.05).