Incisional and excisional biopsy

The histology was diagnosed by Dr. Raj Kapur, Seattle Children’s Hospital, Department of Pathology.  Histologic evaluation revealed a cystic structure lined by thin and keratinized epithelium (Fig 3) and filled with layers of keratin.  The wall of the cyst contained sebaceous glands and occasional hair follicle. 

Figure 3.This is a gross photograph of the nodule after it was removed from the floor of mouth.  It is whitish-yellow in color.

Figure 5.Low power (x100) histology shows a cystic structure lined by orthokeratin with a granular cell layer underneath and supported by a thin fibrous connective tissue wall.  The lumen is filled with keratin.

Figure 6.High power (x200) histology shows a closer look of the connective tissue wall containing sebaceous glands.