COM November 2013

This is a 23-year-old Asian male referred by his general dentist for a deeply impacted tooth # 32 associated with a very large, scalloped and multilocular radiolucency starting from tooth #28 and extending superiorly into the high ramus (Figure 1). This lesion was not expansile or symptomatic in any other way. It was discovered on routine dental examination. The radiolucency shows evidence of cortical bone perforation in the areas of teeth #s 28-30 and the angle of the mandible. Teeth #s 29 & 30 show evidence of root resorption. All associated teeth were vital.

Figure 1. This is a CBCT panoramic view taken at the first clinical presentation. The radiograph demonstrates a very large scalloped radiolucency with slight multilocularity. It starts anteriorly from tooth #28 and progresses posteriorly to the high ramus. Note the root resorption involving teeth #s 29 & 30. Also note the cortical bone perforation apical and between teeth #s 28 & 30. Cortical perforation is also noted at the angle of the mandible.

The patient’s past medical history is unremarkable.

This large radiolucency is of unknown duration and is asymptomatic. It involves the body, angle, and the ramus of the right mandible. All teeth are vital. Tooth # 32 is deeply impacted. Clinical examination and radiographic findings revealed no evidence of swelling and the patient denied any pain or parasthesia.

Figure 1. This is a CBCT panoramic view taken at the first clinical presentation. The radiograph demonstrates a very large scalloped radiolucency with slight multilocularity. It starts anteriorly from tooth #28 and progresses posteriorly to the high ramus. Note the root resorption involving teeth #s 29 & 30. Also note the cortical bone perforation apical and between teeth #s 28 & 30. Cortical perforation is also noted at the angle of the mandible.

Treatment

Under local anesthesia, an incisional biopsy was performed and a small specimen was submitted for histologic evaluation. Following an initial diagnosis, the lesion was removed in its entirety under general anesthesia at Overlake Hospital Medical Center.

Incisional Biopsy

Histological examination revealed multiple pieces of soft tissue composed of a cystic structure and keratin fibers (Figures 2-4). The cystic structure is lined by uniformly thin and keratinized epithelium and supported by a fibrous connective tissue wall (Figures 2 & 3). The lining epithelium is covered by a thin layer of parakeratin and orthokeratin (Figures 2 & 3). The lumen of the cyst contains keratin fibers (Figure 4). The connective tissue wall comprises the bulk of the specimen. It is myxoid in most parts and focally infiltrated by a small cluster of lymphocytes with occasional plasma cells.

Figure 2. Low power (x100) H & E stained histology shows a cystic structure lined by uniformly thin, keratinized and slightly corrugated stratified squamous epithelium. The latter is supported by loose and myxoid fibrous connective tissue wall.

Figure 3. Higher power (200) H & E stain histology shows the thin and keratinized stratified squamous epithelium to be focally artifactually split from the connective tissue. It also shows focal basal cells arranged in a palisaded manner.

Figure 4. Higher power (200) H & E stain histology shows keratin fibers in the lumen of the cyst.