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Polyomavirus and Related Diseases · Review
Dermatology · August 14, 2026
A consensus or society position rather than new primary data.
This is a clinically oriented narrative review for dermatologists on Merkel cell carcinoma, covering epidemiology, diagnosis, staging, prognostic factors, and treatment. It summarizes current evidence on the role of histopathology, immunohistochemistry (cytokeratin 20, MCPyV markers), FDG-PET/CT imaging, emerging biomarkers (circulating tumour DNA, MCPyV oncoprotein antibodies), and immunotherapy (avelumab, pembrolizumab, nivolumab, retifanlimab) in advanced disease, while highlighting disparities in global access to diagnostic and therapeutic tools.
Review. Dermatologists managing Merkel cell carcinoma; patients with MCC, particularly elderly, immunosuppressed, and fair-skinned individuals.
MCC mortality rates exceed melanoma at comparable stages Incidence increasing worldwide, particularly among elderly, immunosuppressed, and fair-skinned individuals Immune checkpoint inhibitors (avelumab, pembrolizumab, nivolumab, retifanlimab) have improved outcomes in advanced disease
No primary efficacy or safety data reported for immunotherapy agents MCC mortality rates exceed melanoma at comparable stages
Dermatologists should recognize both classic and atypical presentations of MCC to avoid delayed diagnosis. Recent advances in immunotherapy, imaging, and biomarkers have improved disease monitoring and treatment, but access disparities remain globally.
A clinically oriented mini-review synthesizing current evidence on MCC epidemiology, diagnosis, staging, prognostic factors, and multidisciplinary management for dermatologists; no new primary data or trial results reported.
Dermatologists should recognize both classic and atypical presentations of MCC to avoid delayed diagnosis. Recent advances in immunotherapy, imaging, and biomarkers have improved disease monitoring and treatment, but access disparities remain globally.
Graded across the dimensions that decide whether you should act, each from what the source actually supports. There is no single score, and where a dimension was not assessed it says so.
What is missing. This record has no reported figures. That is a gap in the analysis, not a judgement about the study.
Background: Merkel cell carcinoma (MCC) is a rare but highly aggressive cutaneous neuroendocrine malignancy with mortality rates exceeding melanoma at comparable stages. Its incidence is increasing worldwide, particularly among elderly, immunosuppressed, and fairskinned individuals. Clinically, MCC often presents as a rapidly enlarging, asymptomatic nodule on sun-exposed skin, although atypical locations and morphologic variants may delay recognition. Summary: This clinically oriented mini-review summarizes current evidence most relevant to dermatologists regarding the epidemiology, risk factors, clinical presentation, histopathology, immunohistochemical diagnosis, staging, imaging, prognostic factors, circulating biomarkers, and treatment of MCC. Diagnosis relies on histopathology and immunohistochemistry, with cytokeratin 20 and Merkel cell polyomavirus (MCPyV)-related markers playing important roles in distinguishing MCC from other small round blue cell tumors. Imaging modalities, particularly FDG-PET/CT, are essential for accurate staging and surveillance. Prognosis is influenced by tumor size, stage, immune status, age, and viral status. Emerging biomarkers such as circulating tumor DNA and MCPyV oncoprotein antibody titers are increasingly relevant for disease monitoring. Management is stage-specific and multidisciplinary, involving surgical excision, radiotherapy, and immune checkpoint inhibitors such as avelumab, pembrolizumab, nivolumab, and retifanlimab, which have improved outcomes in advanced disease. Key Messages: MCC is an uncommon but highly lethal skin cancer that requires early recognition, accurate staging, and multidisciplinary management. Dermatologists should be aware of both classic and atypical presentations to avoid delayed diagnosis. Recent advances in imaging, biomarkers, and immunotherapy have improved disease monitoring and treatment, but important global disparities remain in access to diagnostic tools and modern therapies.
Taken from the source record, never inferred. Follow any of these and new work involving them reaches your briefing.