Incisional and excisional biopsy

Histologic examination revealed an odontogenic cystic structure and a benign neoplasm of odontogenic epithelial origin.  The latter is either associated with or arising from the odontogenic cyst.  This neoplasm is also cystic and is made up of neoplastic lining epithelium, epithelial islands within the superficial connective tissue and a fibrous connective tissue wall.  The lining epithelium shows changes within the basal and parabasal cell layers consistent with those of an ameloblastoma.  The basal cell layer is columnar and palisaded with polarized nuclei (Figs 3 & 4) with multiple layers of spindle shaped epithelial cells.  In focal areas, epithelial islands with palisaded and polarized periphery and stellate reticulum cells in the center are noted in close proximity of the lining epithelium (Fig 5).  Also, in focal areas, a true cystic structure with non-keratinized stratified squamous epithelium consistent with a dentigerous cyst is identified. 

Figure 3. Low power (x40) histology shows a benign cystic neoplasm of odontogenic epithelial origin.  Note the palisaded columnar epithelial cells with dark nuclei present at the basal cell layer.  These changes are consistent with early neoplastic changes. 

 

Figure 4. Higher power (100) histology shows the cystic neoplasm with a more proliferative lining epithelium.  Again, note the palisaded and polarized basal cell layer with multiple layers of stellate reticulum-type epithelium above the basal cell layer. 

 

Figure 5. Higher power (200) histology shows the cystic neoplasm with epithelial islands in the superficial connective tissue wall.  The epithelial islands have palisaded and polarized borders with reversed polarization and a center filled with stellate reticulum.