Dermatologic Manifestations of Merkel Cell Carcinoma Guidelines

Updated: Mar 24, 2023
  • Author: Meghana Agni, MD; Chief Editor: William D James, MD  more...
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Guidelines Summary

Below is a combined summary of updated clinical guidelines on Merkel cell carcinoma by the National Comprehensive Cancer Network (NCCN) (2018) and a European consensus‒based interdisciplinary group (European Dermatology Forum, European Association of Dermato-Oncology [EADO], and European Organisation of Research and Treatment of Cancer [EORTC] [2015]). [13, 52, 120]

Cutaneous clinical features are not sufficient to make a diagnosis of Merkel cell carcinoma. Rather, histopathological (including immunohistochemical) evaluation of a skin biopsy specimen is mandatory to establish a pathologic diagnosis.

Whole-body positron-emission tomography with fluorodeoxyglucose (PET-FDG) scanning; CT with contrast of the neck, chest, abdomen, and pelvis; and/or brain MRI with contrast (in the United States) and ultrasound of the locoregional lymph nodes (in Europe) are helpful tools to evaluate for the presence of metastasis in the initial workup. Sentinel lymph node biopsy (SLNB) is recommended for patients without clinical evidence of regional lymph node involvement, and fine-needle aspiration or core needle biopsy is recommended for those with clinically palpable lymphadenopathy.

Surgical excision with 1- to 2-cm margins is the recommended management for primary tumors, potentially with adjuvant radiation therapy.

Radical lymphadenectomy is recommended for patients who have regional lymph node involvement, and adjuvant radiotherapy can be considered based on risk factors, especially in patients with multiple affected lymph nodes or extracapsular extension.

In the case of regional or distant metastases or recurrence, a multidisciplinary tumor board should be consulted to ascertain an appropriate management.

Checkpoint immunotherapies are the preferred systemic therapy for metastatic disease, preferably through enrollment in a clinical trial. 

Multiple- or single-agent chemotherapy achieves high remission rates in unresectable, metastatic Merkel cell carcinoma; however, responses are usually short-lived.

Close clinical follow-up is critical, with complete skin and lymph node evaluation every 3-6 months for 3 years and every 6-12 months thereafter.