What is a characteristic feature of Paget cells in extramammary Paget disease?

Paget cells are neoplastic cells commonly associated with extramammary Paget disease, a skin condition that primarily affects the vulvar or perianal region. A characteristic feature of Paget cells is that they are keratin positive. This means that when a histological examination is performed, these cells show positivity for keratin markers, which indicates that they have undergone keratinization.

This keratin positivity reflects their epidermal origin and plays a role in differentiating them from other types of neoplastic or inflammatory cells that may be present in the skin. The positivity for keratin can be identified using specific immunohistochemical stains, which helps pathologists confirm the diagnosis of extramammary Paget disease.

Other options, such as keratin negativity, melanin presence, or positivity for estrogen receptors, do not describe the feature of Paget cells in this context. Keratin negativity would suggest a different cell type, melanin presence indicates a potential melanocytic lesion, and estrogen receptor positivity is not a defining characteristic of Paget cells themselves. Therefore, the keratin positive nature of Paget cells is essential for their identification and understanding of extramammary Paget disease.