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Updated: Dec 5, 2025
Merkel Cell Polyomavirus Infection and Detection
Published on: February 7, 2019
Metastatic Merkel Cell Carcinoma Masquerading as Multiple Immune-Related Adverse Events
Farees Saqlain1, Sophia Z Shalhout1,2, Kevin S Emerick1,3,4
1Harvard Medical School, Boston, MA, USA.
Abstract:
Merkel cell carcinoma is a rare cutaneous neuroendocrine carcinoma with a high rate of regional and distant metastasis and mortality. Here, we report a novel case of Merkel cell carcinoma which presented as a primary lesion to the left cheek with regional lymph node involvement and was treated with pembrolizumab and radiation. Widely metastatic disease eventually revealed on autopsy clinically mimicked immune-related organ insult leading to management with immunosuppressants. The patient also had a biopsy-confirmed immune-related cutaneous adverse event during admission. The case highlights a rare circumstance in which disease progression masqueraded as multiple immune-related end-organ adverse events. Contribution of on-target anti-PD-1 toxicity remains a possibility.
Insights
Merkel cell carcinoma progression mimicked immune-related adverse events, complicating treatment. This rare case highlights challenges in distinguishing disease spread from immunotherapy side effects.
Area of Science:
- Oncology
- Immunology
- Dermatology
Background:
- Merkel cell carcinoma (MCC) is a rare, aggressive neuroendocrine skin cancer with high metastatic potential.
- Early detection and treatment are crucial due to high mortality rates.
Observation:
- A case of MCC presented on the left cheek with lymph node involvement, treated with pembrolizumab and radiation.
- Autopsy revealed widely metastatic disease that clinically resembled immune-related organ damage, leading to immunosuppressant therapy.
- The patient experienced a biopsy-confirmed immune-related skin reaction during hospitalization.
Findings:
- Disease progression in this MCC case mimicked multiple immune-related end-organ adverse events.
- Distinguishing between MCC metastasis and immune-related adverse events (irAEs) posed a significant clinical challenge.
Implications:
- This case underscores the importance of vigilant monitoring for both disease progression and irAEs in MCC patients treated with immunotherapy.
- Understanding potential overlaps in clinical presentation is vital for accurate diagnosis and optimal patient management.
- Further research into on-target anti-PD-1 toxicity may clarify its role in such presentations.
