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Case of the Month Archives

COM January 2018 Diagnosis

Large unilocular radiolucency with scalloped border, anterior mandible

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This is a 44-year-old Caucasian male who was referred by his general dentist due to the incidental finding of a large radiolucency discovered on a routine periapical (PA) dental radiograph.

Case of the Month Summary

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The differential diagnosis for a radiographic presentation of a well-circumscribed and unilocular radiolucency with a scalloped border should include odontogenic keratocyst (OKC) high on the list. The clinical presentation of very little expansion is consistent with the clinical behavior of OKC, since this cyst is usually not expansile, with some exceptional cases that are mildly or very expansile. The age of this patient falls into the main age range of OKCs (10-40), though OKCs can occur at any age. The site in the anterior mandible, however, is not consistent with the clinical presentation of OKC since it is more common in the posterior mandible extending to the ramus. The histology in this case is not that of odontogenic keratocyst.

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The radiographic findings of a unilocular radiolucency with a scalloped border squeezing between teeth should include traumatic bone cavity especially when not expansile clinically. Traumatic bone cavity usually occurs between premolars and molars, but can occur in the anterior mandible as well. The patient’s gender is consistent with typical cases of TBC, but not his age. Traumatic bone cavity of the jaws tends to occur in young patients between the ages of 10 and 20 and only rarely in those over 30. Traumatic bone cavity has been reported in African-American females who are over the age of 30 and have florid cemento-osseous dysplasia. The histology in this case is not consistent with that of traumatic bone cavity.

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A radiolucent lesion present in the anterior mandible and reaching the midline could also be a central giant cell granuloma (CGCG); therefore, this condition should be on the differential diagnosis. Over 60% of CGCG cases occur in patients younger than 30 years of age, with twice as many occurrences in females as in males. This patient is male, and he is slightly older than the typical age range for this condition. Over 70% of cases occur in the mandible anterior to the first molar tooth, which is consistent with this clinical presentation. However, CGCG is usually expansile; this lesion is not. The histology in this case is also not consistent with CGCG.

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Glandular odontogenic cyst (GOC) is another condition that should be present on the differential diagnosis of a unilocular radiolucency with a scalloped border. GOC is a developmental cyst that can be aggressive at times, perforating bone. GOC is of tooth origin and occurs three times as often in the mandible as in the maxilla. It tends to be more common in the anterior mandible; other reports indicate that it is also common in the posterior mandible. It is more common in adults with an average age of 49 at occurrence and a slight male predominance; these characteristics are consistent with this patient’s age and gender. That said, it has been reported in a wide age range. The histology in this case is that of GOC.

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