Fig. 8.
From: Giant peripheral ossifying fibroma with coincidental squamous cell carcinoma: a case report
Histopathological findings (hematoxylin–eosin and immunohistochemical stain). The body of the tumor is composed of spindle-shaped cells proliferating with collagenous fiber, and marked ossification can be seen as well. Squamous cell carcinoma is found in the superficial part of the lesion (squamous cell carcinoma; arrow, ossification; arrowhead). Positive staining of CK17 and Ki67 observed in atypical squamous epithelia supports the diagnosis of squamous cell carcinoma, and focal SMA staining indicates myofibroblastic differentiation