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Cysts of the Oral and Paraoral Region 2- Developmental Periodontal Cysts: i. Developmental lateral Periodontal Cyst: Definition: A non-inflammatory developmental cyst that occurs adjacent or lateral to the root of a vital tooth. Etiology: The origin is related to prolife...

Cysts of the Oral and Paraoral Region 2- Developmental Periodontal Cysts: i. Developmental lateral Periodontal Cyst: Definition: A non-inflammatory developmental cyst that occurs adjacent or lateral to the root of a vital tooth. Etiology: The origin is related to proliferation of rests of odontogenic epithelium at the lateral side of the root of adjacent vital tooth (the cause of the epithelial proliferation is unknown and not due to an inflammatory process). Clinical features: Age: Any age, most common age from 40 to 60 years. Sex: Male to female ratio 2:1. Site: In the mandibular premolar and canine region. In the maxilla the lateral incisor region is a common site. Appearance: It often presents no signs or symptoms and may be discovered during routine radiographic examination of the related tooth. Occasionally, when the cyst is located on the labial surface of the root, there may be a slight bulge, although the overlying mucosa is normal. The related tooth is vital. If the cyst becomes infected, its signs and symptoms may resemble those of a lateral periodontal abscess. Radiographic features: Lateral developmental periodontal cyst appears as a radiolucent area. Small, seldom over 1cm in diameter. May or may not be well circumscribed with an opaque margin. 13  Cysts of the Oral and Paraoral Region Lateral developmental Cyst. Radiolucent lesion between the roots of the vital mandibular canine and first premolar. (1) Histopathologic Features: The cystic cavity is lined by stratified squamous epithelium which is thin and composed of one or two layers of cells. Some cysts show focal nodular thickenings of the lining epithelium. These often have a whorled appearance and the cells may have clear cytoplasm and small deeply staining nuclei due to accumulation of glycogen. Parakeratin or orthokeratin formation by the epithelial lining. Inflammatory cells may be present in the connective tissue wall but this is a secondary reaction when the cyst becomes infected. 14  Cysts of the Oral and Paraoral Region A A: This photomicrograph shows a thin epithelial lining with focal nodular thickenings. (1) B B: These thickenings often show a swirling appearance of the cells. (1) iii. Botryoid odontogenic cyst Definition: A developmental odontogenic cyst lined by non-keratinized epithelium, occurring on the lateral aspect or between the roots of erupted teeth. It is the multicystic variant of the developmental lateral periodontal cyst. The word Botryoid comes from Greek botruoeidēs, meaning ‘bunch of grapes. Gross specimen of a botryoid odontogenic cyst. Microscopically, this grapelike cluster revealed three separate cavities. (1) Etiology: It is believed to arise from rests of the dental lamina, reduced enamel epithelium, or rests of Malassez. 15  Cysts of the Oral and Paraoral Region Clinical Features: Age: Any age, commonly 50-60 years. Sex: Slight male predilection. Appearance: Well-circumscribed painless swelling of the bone. It occurs mostly in the mandibular premolar area. Radiographic features: Appears as a multilocular radiolucent area, lateral to the root surface of a tooth. Well-demarcated and often exhibits a corticated margin. Histopathology: It is lobulated, each lobule is lined by thin stratified squamous epithelium, which contains areas of thickenings “plaques”. The lining may contain cells with clear cytoplasm due to accumulation of glycogen. The lobulations are separated by thin fibrous septa. Botryoid odontogenic cyst showing multiple cystic spaces lined with thin epithelium with nodular thickenings. (2) Treatment: Enucleation. Due to the high potential of incomplete removal, it has a high recurrence rate. 16  Cysts of the Oral and Paraoral Region iii. Developmental Gingival Cyst of Adulthood Def.: A non-inflammatory developmental cyst occurring adjacent to a vital tooth, at the gingiva. It is considered to be the soft tissue counterpart of the lateral developmental cyst. Etiology: Gingival cyst arises from remnants of dental lamina in the soft tissue (epithelial rests of Serre’s). Clinical Features: Age: Any age, commonly 40-60 years. Sex: Males and females are almost equally affected. Appearance: The gingival cyst appears as a small, well-circumscribed painless swelling of the gingiva, less than 1cm in diameter. It may involve the free or attached gingiva and sometimes the gingival papilla itself. The lesion has the same color as the adjacent normal mucosa but sometimes larger lesions erode the underlying bone and assume a slightly bluish discoloration. Radiographic Features: Gingival cyst of the adult is a soft tissue lesion and does not manifest itself on dental x-ray films (negative). Histopathologic Features: Gingival cysts show epithelial lined cavity; the epithelium is very thin, flattened stratified squamous epithelium. In most cases, it has a non- keratinized epithelium, but occasionally, some keratin formation may be seen. 17  Cysts of the Oral and Paraoral Region Gingival Cyst of the Adult. Low-power photomicrograph showing a thin-walled cyst in the gingival soft tissue. (1) v. Gingival Cyst of the Newborn Bohn’s nodules The preferred name for that cyst is “Dental Lamina Cyst of Newborn” because gingiva is a structure related to teeth, which are not present in newborns. These are multiple white nodules of not more than a few millimeters in diameter on the alveolar ridge of a newly born infant. They originate from remnants of the dental lamina which proliferate to form small cysts. These lesions appear to be asymptomatic. In most cases these cysts degenerate, rupture and resolve spontaneously. Histopathologic Features: Thin epithelial lining usually two or three layers thick and the lumen is usually filled with desquamated keratin. 18