Case of the Month

This is an 89-year-old female whose chief complaint is that her dentures are not fitting on the right side of her lower jaw. The patient has no physical symptoms from the mass. She has no pain, no difficulty speaking and swallowing and no paresthesia of the lip and chin. Her main concern is her inability to wear a lower denture. The CT scan imaging shows a large and expansile mixed radiolucent and radiopaque mass in the right mandible in area of the premolar teeth (Figure 1).

Figure 1 This is a CBCT imaging taken at the clinical presentation. Note the large, well-circumscribed mixed radiolucent and radiopaque mass at the right mandible. There is prominent buccal and lingual expansion.

Her past medical history includes hypertension and diabetes. She had treatment for breast cancer in 1998.

CBCT reveals a spherical radiolucent and radiopaque expansile mass in the right mandible extending toward the inferior border, but not through the inferior border of the mandible. It is well demarcated and has buccal and lingual expansion but does not encompass the adjacent teeth.

Under general anesthesia, the lesion was resected.

Multiple pieces of hard and soft tissue showed layers and layers of folded, focally papillary and highly keratinized ribbons of epithelium and connective tissue (Figure 2). cystic epithelial islands are present. Also present are prominent calcified viable woven bone trabeculae uniformly scattered throughout the connective tissue (Figure 2). This cystic neoplasm is lined by epithelium which is producing thick layers of parakeratin (Figure 3). The epithelium is thin in some areas and thick and proliferative in others (Figures 2-4). The basal cell layer is palisaded and shows focal reverse polarization (Figure 3-4).

Figure 2 Low power (x40) H & E histology demonstrating layers of folded, focally papillary, and highly keratinized epithelium supported by connective tissue. Note foci of calcified bony trabeculae.

Figure 3 Higher power (x 100) H & E histology demonstrating a closer look at the layers of highly keratinized epithelium and also islands of epithelium with the center filled with keratin. These islands may also represent tangential cuts of the papillary portions of this tissue.

Figure 4 High power (x 200) H & E histology demonstrating thicker keratinized epithelium with islands formation and periphery with palisaded basal cell layer.