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Neuroradiology Case of the Week

Case 270

Ashwani K. Sharma, MD, Brian Sorensen, MD,
and P-L Westesson, MD, PhD, DDS

Clinical Presentation: Patient is a 14-year-old male who presented with slowly progressive left-sided jaw swelling.

Imaging Findings: Dentigerous cysts are well-circumscribed, radiolucent, expansile cyst surrounding crown of unerupted, embedded or impacted tooth. They are most commonly located in the mandible and are usually unilocular.

Differential diagnosis includes radicular cyst (simple periapical cyst), odontogenic keratocyst (multilocular cyst without unerupted tooth), and ameloblastoma (with enhancing mass).

Diagnosis: Dentigerous cyst

Discussion: Dentigerous cysts are odontogenic cysts which enclose the crown and are attached to the neck of an unerupted tooth [1]. Single dentigerous cysts are the second most common odontogenic cysts after radicular cysts. They generally appear during tooth development in young patients. The mandibular third molar and maxillary canine are most frequently involved. There is usually no pain or discomfort. When cysts are small, they are usually discovered in radiographic examinations that are taken to investigate other symptoms or a failure of tooth eruption, but when cysts enlarge there are asymptomatic facial swellings. Radiographs show a unilocular radiolucent lesion with well-defined sclerotic margins that is associated with the crown of an unerupted tooth. Radicular resorption of teeth in the region of the lesion is common. The mechanism of development of the dentigerous cyst has until now remained unclear. It has recently been reported that inflammation progressing from the root apex of the deciduous tooth brings about development of the dentigerous cyst around the unerupted permanent tooth [2].
     Since the cyst may increase in size, the indicated treatment is surgical removal of lesion and involved teeth, or decompression to salvage the involved teeth [3].

References:

1. Freitas DQ, Tempest LM, Sicoli E, Lopes-Neto FC. Bilateral dentigerous cysts: review of the literature and report of an unusual case. Dentomaxillofac Radiol. 2006 Nov;35(6):464-8. [Medline]
2. Benn A, Altini M. Dentigerous cysts of inflammatory origin. A clinicopathologic study. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1996 Feb;81(2):203-9. [Medline]
3. Motamedi MH, Talesh KT. Management of extensive dentigerous cysts. Br Dent J. 2005 Feb 26;198(4):203-6. [Medline]