Merkel cell carcinoma with squamous and sarcomatous differentiation

Area of Science:

• Oncology
• Dermatopathology
• Cell Biology

Background:

• Merkel cell carcinoma (MCC) is an aggressive neuroendocrine skin cancer.
• Historically, MCC was thought to originate from neural crest cells, but recent evidence suggests an epidermal origin.

Observation:

• A rare case of MCC in a 94-year-old woman presented with three distinct morphologic patterns: typical small cells, squamous differentiation, and spindle cells.
• Metastatic disease in lymph nodes exhibited only the small cell and spindle cell patterns.

Findings:

• This is the first reported case of MCC exhibiting these three differentiation patterns at initial presentation.
• The diverse morphology challenges the traditional understanding of MCC origins.

Implications:

• The findings support the hypothesis that MCC may arise from multipotent epidermal stem cells.
• This could lead to new diagnostic and therapeutic strategies for Merkel cell carcinoma.