Figure 3.

Histology and immunohistochemistry. Tumor biopsy (pretreatment): (a) solid mass of cohesive, discretely pleomorphic cells of intermediate size with hyperchromatic, pleomorphic nuclei (H&E, original magnification: ×100). (b) Immunohistochemistry revealed nuclear positivity for p63 (×200). Strong cytoplasmatic positivity for CK5/6, ((c), ×400). CK7 staining results in only focal weak positivity of few tumor cells ((d), ×200). Histology of resection specimen (after treatment). (e) Overview of tumor extension, large areas of fibrosis were seen; small circumscribed area of vital tumor is indicated by arrows (H&E, ×25). Closer view on vital tumor cells resembling pretreatment morphology ((f), H&E ×200).