Fatal outcome after immunotherapy in metastatic Merkel cell carcinoma of unknown primary cause

Yohan Depierre1, Amina Faiza Chouiter-Djebaili2, Hervé Zender1,3,4

  • 1Service of Internal Medicine, Department of Medicine, Network Hospital Neuchâtel, La Chaux-de-Fonds, Switzerland.

BMJ Case Reports
|February 24, 2026
PubMed

Insights

Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer. Immunotherapy with pembrolizumab can be effective but carries a risk of acute renal failure, requiring careful patient monitoring.

Area of Science:

  • Oncology
  • Immunology
  • Nephrology

Background:

  • Merkel cell carcinoma (MCC) is a rare but aggressive skin cancer with high mortality.
  • Metastatic MCC treatment options are limited, with anti-programmed cell death protein 1 (PD-1) immunotherapy now a primary strategy.

Purpose of the Study:

  • To report a case of stage IV MCC treated with pembrolizumab.
  • To highlight the potential risk of acute renal failure associated with pembrolizumab therapy in MCC patients.

Main Methods:

  • Case report of an elderly female patient with stage IV MCC.
  • Initiation of pembrolizumab therapy for metastatic disease.
  • Monitoring for adverse events, specifically renal complications.

Main Results:

  • The patient developed acute renal failure after the first pembrolizumab infusion.
  • This case underscores the high pathogenicity of MCC and potential immunotherapy-related adverse events.

Conclusions:

  • Pembrolizumab is a key treatment for advanced MCC but requires vigilant monitoring for renal complications.
  • Proactive management is crucial to anticipate and prevent adverse effects during immunotherapy for metastatic MCC.

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