Merkel cells--review on developmental, functional and clinical aspects

Area of Science:

• Dermatology
• Neuroendocrinology
• Oncology

Background:

• Merkel cells (MCs) are neuroendocrine cells in the epidermis, crucial for touch sensation.
• Their density varies by body site, and they are challenging to identify with standard light microscopy.
• Cytokeratin 20 is a specific marker for MC identification.

Purpose of the Study:

• To review the function, development, and clinical importance of Merkel cells.
• To discuss the origin of Merkel cells, whether neural crest or epidermal.
• To highlight Merkel cell carcinoma (MCC), its diagnosis, and treatment.

Main Methods:

• Literature review of Merkel cell function, development, and clinical significance.
• Discussion of diagnostic methods including light microscopy, electron microscopy, and immunohistochemistry (Cytokeratin 20).
• Review of Merkel cell carcinoma (MCC) classification, diagnosis, and treatment modalities.

Main Results:

• Merkel cells are post-mitotic neuroendocrine cells in the epidermal basal layer.
• Their origin remains debated: neural crest or epidermal keratinocyte differentiation.
• Merkel cell carcinoma (MCC) is an aggressive malignancy, often in the head and neck, diagnosed via histology and immunohistochemistry.

Conclusions:

• Merkel cells play a vital role in cutaneous neuroendocrine function.
• Understanding MCs is critical for diagnosing and managing MCC.
• MCC treatment involves surgery for primary tumors and oncological therapy for advanced stages.