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Updated: Aug 15, 2026

A 3D Organotypic Melanoma Spheroid Skin Model
Published on: May 18, 2018
Cutaneous undifferentiated small (Merkel) cell carcinoma, that developed synchronously with multiple actinic
Abdullah Aydin1, N Emrah Koçer, Mehmet Bekerecioglu
1Department of Pathology, Medical Faculty, Gaziantep University, Gaziantep, Turkey.
Abstract:
Merkel Cell Carcinoma (MCC) is an uncommon undifferentiated neuroendocrine tumor, arising in skin mainly on sun-exposed areas. We present an unusual case of primary cutaneous undifferentiated small cell carcinoma that co-existed with six other lesions; 2 actinic keratoses, 3 squamous-cell carcinomas and a basal-cell carcinoma. HE stained sections revealed MCC located in the mid-dermis, co-existing with severe actinic keratosis. Immunohistochemically, the tumor cells reacted to cytokeratin 20, epithelial membrane antigen, chromogranin and neuron specific enolase. This is an unusual case of cutaneous MCC co-existing with six other different lesions. The concurrent development of MCC, squamous-cell and basal-cell carcinoma in the same patient indicates the pluripotent epidermal stem cell origin of these tumors. Further research is needed to enlighten the factors inducing this divergent differentiation.
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