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Case of the Month Archives

COM Sept. 2016 Diagnosis

Small and unilocular radiolucency between teeth #s 27 & 28

Can you make the correct diagnosis?

This is a 39-year-old female who presented with pain and mild swelling in the superior third of the root between teeth #s 27 & 28.

Sorry, you are incorrect!

With the exception of the patient’s gender, almost all of the clinical and radiographic characteristics of this condition are consistent with those of lateral periodontal cyst (LPC). The site high in the roots, the age of the patient, the well-demarcated unilocular radiolucency and the lack of tooth movement is consistent with the clinical behavior of LPC. The blue color upon raising a flap and the liver-like dark brown color of the gross specimen are unusual in LPC, but they are not definitively excluded in cysts where bleeding has occurred. Lateral periodontal cyst should therefore remain on the differential diagnosis as the most likely diagnosis until the biopsy results are established. Since this cyst is usually not vascular, the gross appearance of a liver-like color argues against a diagnosis of LPC. The histology is not consistent with LPC.

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Generalized: The presentation in this case does not indicate generalized periodontitis because all other areas of the alveolar bone and gingiva are normal. There is no evidence of gingivitis, pockets or bone loss. The patient is also somewhat young for periodontitis. She has no systemic diseases that would cause generalized periodontitis and has good oral hygiene habits.

Localized: The clinical presentation of this case is consistent with localized periodontitis. In particular, the radiolucency of the lesion and its occurrence between teeth and high in the roots raises the possibility of this condition. However, the radiolucency is well demarcated and is round to oval in shape rather than angular or having a vertical defect. Both of these characteristics are unusual in periodontitis. Upon probing of the area, all pocket depths were within normal limits and there was no evidence of gingivitis, which contraindicates a diagnosis of localized periodontitis. Occlusal trauma can also cause localized bone loss, but no such trauma can be identified in this case. The histology is also not consistent with periodontitis.

Periodontitis can be vascular and red. However, the gross appearance of a dark-brown (liver-like) color is not typical of periodontitis. The histology is not consistent with periodontitis.

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The site of occurrence, age of the patient, size of the lesion, and the well-demarcated nature of this radiolucency with no obvious swelling is consistent with the clinical presentation of squamous odontogenic tumor (SOT). This is a benign neoplasm of odontogenic epithelial origin that has a tendency to present with pain. This patient did not report pain in the area. The gross appearance of a dark-brown color is not consistent with SOT. Grossly, SOT is a solid tumor made up of connective tissue and epithelial islands and is usually grossly tannish in color. The histology in this case is not consistent with SOT.

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The site of occurrence anterior to the first molar is consistent with the clinical presentation of central giant cell granuloma (CGCG). The small unilocular radiolucency between teeth in the superior third of the roots, however, is highly unusual for this condition. The gender of the patient is consistent with a diagnosis of CGCG but her age is somewhat unusual, since 60% of CGCG cases occur in patients under the age of 30. The bluish color on clinical examination is consistent with the typical clinical presentation of CGCG reflecting through thin bone. CGCG is very vascular, and the gross presentation of a liver-like color is therefore typical of this condition. The histology in this case is consistent with central giant cell granuloma. It is good practice in cases like this to always rule out brown tumor of hyperparathyroidism since the two histologies are similar.