Bohn's nodules

Clinical
Bohn’s nodules, Epstein’s pearls, and gingival cysts of the newborn: A new etiology and classification
PROVIDED BY DAVID M. LEWIS DDS MS OUCOD DEPARTMENT OF ORAL AND MAXILLOFACIAL PATHOLOGY Introduction: Alois Epstein (1849-1918), a Prague pediatrician first described the small nodules found in the oral cavity of infants in 1880. He cited the German pediatrician Heinrich Bohn(1832-1888), author of Die Mundkrankheiten der Kinder (Mouth Diseases of Children) for describing Bohn's nodules (mucous-gland cysts).1 Gingival cysts of the newborn (dental lamina cysts) were theorized to have develop from remnants of the dental lamina.2 All three lesions have been described as having different etiologic origins, different histologic features, and different locations in the oral cavity.Fromm,1 in his comprehensive review of 1,367 newborn infants, conducted one of the first and largest studies of these cysts since their discovery nearly a century earlier. He concluded that cysts were quite common (found in 79% of infants in his study) and that there were three distinct types both histologically and clinically. Epstein’s pearls are those found along the midpalatine raphe andderived from epithelial tissues trapped along the raphe as the fetus grows. Bohn’s nodules are those found along the buccal and lingual aspects of the dental ridges, and are derived from mucous gland tissues; they are histologically different from Epstein’s pearls. Gingival cysts of the newborn are those found on the crest of the maxillary and mandibular dental ridges, and are derived from remnants ofthe dental lamina. The two terms, Bohn’s nodules and Epstein’s pearls, have been used interchangeably in the literature and have also been used to describe the gingival cyst of the newborn which is thought to be of odontogenic origin. Currently the preferred terminology is palatal cysts of the newborn for both Epstein’s pearls and Bohn’s nodules, and gingival cysts of the newborn for those ofdental origin.3 It has also been noted that since these cysts are most common near the midline at the junction of the hard and soft palates, it is usually difficult to ascertain clinically whether they are arising from epithelium entrapped by fusion of the palate or from the developing salivary glands. with the mucosal surface.3 Prognostically, the cysts are innocuous lesions and require no treatment.They are self-limiting and are rarely observable several weeks after birth. Presumably, the epithelium degenerates, or the cysts rupture onto the mucosal surface.3

Fig. 2. Gingival cyst of newborn. Gingival (alveolar) cysts of the newborn (Fig. 2.) are common lesions, reported in up to one-half of all newborns, presenting as individual cysts no more than two to three mm in diameter. They aremore common in the maxilla than the mandible. On histologic examination, they are composed of a parakeratinized stratified squamous epithelial lining with a lumen containing keratinous debris.3 The prognosis is good and no treatment is required. The lesions spontaneously involute as a result of rupture of the cyst and resultant contact with the oral mucosal surface. The lesions are rarely seen afterthree months of age.3 Discussion: The similarities between these three lesions are remarkable: they all occur in the oral cavity (palate and dental alveolar arch), they all have identical histologic features (parakeratinized stratified squamous epithelial lining with a lumen containing keratinous debris), and they all behave in a similar manner (spontaneous resolution). However, they all havedifferent etiologic origins and names. The concept of entrapment of epithelium during embryologic development (i.e. fissural cysts) has been questioned in recent years. The fusion of the globular portion of the median nasal process and the maxillary process is now considered to be an elimination of grooves and a merging of growth centers rather than fusion of processes. No epithelial entrapment...