Merkel cell carcinoma (MCC) is one of the most aggressive primary cutaneous malignancies. The clinical diagnosis of MCC is often delayed. Although the rarity of this skin cancer partially explains the low clinical suspicion by physicians, the absence of characteristic clinical features contributes to the delay in diagnosis. Dermatoscopy has proven a useful diagnostic tool in other cutaneous malignancies; however, the dermatoscopic features of cutaneous MCC are unknown.

We performed dermatoscopy on 10 primary cutaneous MCC to describe the dermatoscopic features and correlate these findings with the histopathologic parameters.

Consecutive patients with cutaneous MCC were identified and their tumors were evaluated under dermatoscopy. An 8-point MCC histopathology profile was recorded for each primary tumor in an attempt to correlate individual parameters with dermatoscopic features.

All 10 tumors showed an irregular vascular pattern under dermatoscopy and demonstrated milky-red areas/globules and numerous linear irregular vessels. No correlation was noted between dermatoscopic and histopathologic features.

The patients were from a single institution and tumors evaluated by a single dermatoscopic reviewer. Because of the rarity of this tumor, a small number of tumors were evaluated (10).

MCC exhibits a variety of dermatoscopic vascular patterns, most commonly milky-red areas/globules, polymorphous vessels, and linear-irregular vessels. Although we found no specific dermatoscopic pattern for MCC in our series, the polymorphous vascular pattern was atypical and suggestive of a malignant process. Further studies should be done to investigate the potential correlation between dermatoscopic features and histopathologic parameters.