# Late Metastatic Recurrence of Merkel Cell Carcinoma Nine Years After the Primary Diagnosis

## TL;DR

A rare skin cancer called Merkel cell carcinoma recurred as a metastasis nine years after initial treatment, suggesting the need for longer monitoring.

## Contribution

This case report demonstrates the possibility of late metastatic recurrence in Merkel cell carcinoma beyond the typical three-year window.

## Key findings

- Merkel cell carcinoma recurred as a metastasis nine years after initial diagnosis and treatment.
- The case suggests the need for extended surveillance beyond the current three-year recommendation.
- Clinicians should counsel patients about the low but possible risk of late metastasis.

## Abstract

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer of neuroendocrine origin that has been known to recur and metastasize within the first three years of initial diagnosis. MCC is typically diagnosed with clinicopathologic correlation of a red-purple nodule or flesh colored papule on sun-damaged skin and characteristic immunohistochemical staining. We present a case of a 66-year-old White man who was found to have metastatic MCC over nine years after the initial stage one tumor was diagnosed and treated with Mohs micrographic surgery (MMS) and radiation therapy. This case highlights the importance of defining prognostic biomarkers for each patient with MCC and consideration of extended surveillance beyond the current recommended three years. Clinicians should also be attentive when counseling patients to explain that the risk of late metastasis, although low, is still possible.