Abstract: The early diagnosis of subungual squamous cell carcinoma are rather difficult. The non-invasive examination methods can offer significant assistance to early diagnosis. Relevant literature has reported that under dermatoscopy, scales, crusts, keratin, punctate vessels, hairpin-shaped curved blood vessels and linear irregular blood vessels, white circles could be seen, and the white circles can be regarded as a specific dermatoscopic manifestation of squamous cell carcinoma. This patient presented with a neoplasm under the nail of the right ring finger for 1 year. Under dermoscopy, linear and irregular vascular structures can be seen, with blurred edges, excessive keratinization, local ulcers, and blood scabs. A preliminary diagnosis of subungual squamous cell carcinoma was made based on the clinical manifestations and dermoscopy findings. The diagnosis was identified through histopathology, then an expanded resection of the skin tumor were performed. The finger wound of the patient healed well 2 months after surgery, and there is no restriction on the movement of the finger.

Key words: subungual, squamous cell carcinoma, dermoscopy