Incisional and excisional biopsy

Histologic examination revealed an elongated piece of oral mucosa covered by keratinized epithelium and supported by fibrous connective tissue (Fig 3).  The epithelium was of increased thickness and was covered by a thick layer of parakeratin.  The spinous layer, especially the upper layers, showed epithelial cells with evidence of cytoplasmic clearing with perinuclear keratin condensations (Fig 4).

Figure 3.Low power (x100) histology shows a fragment of oral mucosa with thick spinous layer covered by a thick layer of parakeratin.    Note the epithelial cells throughout the spinous layer especially in the superficial layers exhibiting keratin condensations around the nuclei. 

Figure 4. Low power (x100) histology shows a fragment of oral mucosa with thick spinous layer covered by a thick layer of parakeratin.    Note the epithelial cells throughout the spinous layer especially in the superficial layers exhibiting keratin condensations around the nuclei.