What are the cells of origin and the immunohistochemical profile of Paget disease?
- The Paget cells (intraepithelial large cells with pale pink cytoplasm and large nuclei) are believed to be of apocrine lineage and show immunoreactivity with low-molecular-weight keratins Cam 5.2, CK7, and carcinoembryonic antigen.
- Mucin stain may be positive.
- The differential diagnosis includes pagetoid spread from adjacent CRC and melanoma in-situ. The immunoprofile helps.