The tumor ( Images A & B) shows lobules of cells similar to
basal cells with masses of small keratinocytes surrounded by
larger, palisading cells (Image C) on the periphery of the
lobules. These uniform tumor cells possess large, oval,
elongated nuclei and scant, poorly defined cytoplasm. There are
no intercellular bridges. The nuclear size is relatively uniform
and identifiable mitoses (Image D) are normal, although
variable. The surrounding myofibroblastic stroma (Image C) is
arranged in parallel bundles. There are an abundance of
keratotic cysts and occasional retraction lacunae (Image C)
where the stroma retracts from the tumor. The odontogenic
keratocyst is lined by a two to five layer squamous cell
epithelium with a well-differentiated basal layer. It forms
keratin, possesses no granulocytic cell layer or rete ridges,
and may consist of one large cyst, or multiple microcysts. The
parakeratotic odontogenic cyst (Images E & F) possesses a thin
lining of stratified squamous epithelium with a palisading bas