# Reconstructive Technique in the Treatment of Merkel Cell Carcinoma of the Upper Eyelid: A Case Report

## TL;DR

This case report describes a reconstructive technique for Merkel cell carcinoma on the upper eyelid that balances effective tumor removal with minimal invasiveness.

## Contribution

The paper introduces a novel combination of lateral canthotomy and switch flap for eyelid reconstruction in Merkel cell carcinoma.

## Key findings

- The method successfully reconstructed a large upper eyelid defect without functional or cosmetic issues over 6 months.
- The technique is suitable for defects measuring 13–20 mm and is less invasive than malar flap methods.
- This approach is particularly beneficial for elderly patients with bleeding risks.

## Abstract

Merkel cell carcinoma is a rare highly malignant disease that requires a wide resection and careful reconstruction of the resulting defect. We removed a Merkel cell carcinoma that had developed on the upper eyelid of an 86‐year‐old man and reconstructed the eyelid using a switch flap.

The large size of the defect made it difficult to close the lower eyelid switch harvest site. Because of the patient’s high risk of bleeding, closure of the switch flap donor site using a malar flap and cartilage graft was not performed. Instead, lateral canthotomy and lateral cantholysis were performed, and the ear‐side end of the switch flap donor site was advanced 5 mm toward the nasal side, which allowed closure of the lower eyelid flap donor site.

The switch flap was detached 16 days after the initial surgery. In the 6 months since the surgery, there have been no problems with the function of the eyelids or the cosmetic appearance, or recurrence of the tumor. The results of this case suggest that this method is a good option for large full‐thickness upper eyelid defects of 13–20 mm. Lateral canthotomy with lateral cantholysis is a well‐known procedure, but there have been no reports of its combination with a switch flap.

We believe that this method is positioned between the direct closure and malar flap, and that this method allows for a quick and minimally invasive reconstruction. The treatment of Merkel cell carcinoma requires extensive excision, and it is easy to meet the aforementioned criteria when it occurs in the upper eyelid. Because this carcinoma occurs frequently in older people, who can have a high bleeding risk, this minimally invasive method is useful for treating Merkel cell carcinoma of the upper eyelid.