The compulsion neurosis loosely called cheekbiting may lead to the formation of various changes depending on the anomaly on which the habit becomes fixed: the common transverse ridges along the lines of occlusion, soft nodules termed "diapneusie buccale" produced by sucking through a defect in the dental wall, fibrosis of the oral mucosa from the long-continued administration of diphenylhydantoin in epileptics, and a highly distinctive picture closely resembling moniliasis based on lichen planus and congenital epithelial abnormalities. A patient who showed this variety fixed on white sponge nevus is reported. The term "morsicatio buccarum" is recommended because this form is the only manifestation of the neurosis in which the patient actually bites off pieces of mucous membranes. Microscopic examination is necessary to rule out moniliasis, and biopsy is essential for the diagnosis of white sponge nevus because the compulsive habit may also occur superimposed on lichen planus.
It is postulated that cheekbiting, like the self-inflicted dermatoses on the glabrous skin, is fixed on abnormal tissue. The psychiatric implications of the neurosis are discussed.