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EXPERIENCE & REASON |
Department of Pediatrics, McGill University, Montreal, Quebec, Canada
ABSTRACT
A 4-year-old girl presented to a medical clinic with a painless right facial swelling. The treating physician ordered a radiograph of the sinuses and received a report of "maxillary sinusitis." After appropriate antibiotic treatment, the facial swelling increased, and the mother took the child to her community pediatrician. After a period of observation and additional imaging, the diagnosis of dentigerous cyst was made. After appropriate surgical intervention, the cyst was removed, and over the ensuing 6 weeks the facial swelling gradually diminished. Dentigerous cysts, although uncommon, need to be considered in the differential diagnosis of children with painless facial swelling.
Key Words: ambulatory care • community pediatrics • diagnostic errors • sinus disease
This case report is one of the very few in the pediatric medical literature that remind us that not everything in the maxillary sinus is acute sinusitis. Because dentigerous cysts are rarely reported in the pediatric medical literature, the purpose of this report is to alert pediatricians to their possibility in children with facial swelling.
CASE REPORT
A 4-year-old girl presented to a medical clinic because of a slight right facial swelling. Although there was no fever or sinus tenderness, the attending physician ordered sinus films and the radiologist reported "acute bilateral maxillary and right ethmoid sinusitis... the facial bones are radiologically normal." A 10-day course of cefprozil (250 mg twice daily) was prescribed. Two months later, the child presented to her pediatrician because of a sore right ear, and a diagnosis of otitis media was made; the child was treated with a 3-day course of azithromycin. At the visit, the mother expressed concern that there was still some facial swelling overlying the right maxillary sinus. Physical examination revealed a slight right facial swelling, which was nontender and firm, with no warmth, fluctuation, or discoloration of the overlying skin. The child was afebrile, and the rest of her physical examination was within normal limits. The physician decided to observe her. Six weeks later, the mother called because she was alarmed that the facial swelling was increasing. On examination, her physician noted that the right facial swelling was indeed increasing, and there was some watery discharge from the right eye with no conjunctival injection or redness (Fig 1). Again, the swelling was found to be painless, with no warmth, fluctuation, or discoloration overlying it. The swelling felt firm and "bony." The child underwent additional imaging (Figs 2–4). The radiologic diagnosis was 2 large dentigerous cysts each associated with dental structures. A surgical procedure was performed (Caldwell-Luc excision of cyst and right functional endoscopic sinus surgery, as well as maxillary antrostomy). A cyst-like mass measuring 6.0 x 6.0 x 0.5 cm was excised, along with 2 aberrant tooth-like structures. Multiple sections revealed a cyst lined by a nonkeratinized layer of stratified squamous epithelium (Fig 5). Also present were small tooth-like structures consisting of enamel, dentin, and dental follicle (Fig 6). Therefore, the final diagnosis was a dentigerous cyst arising from an odontoma. The child did well postoperatively, and 6 weeks after the procedure, the facial swelling had decreased considerably. A repeat computed tomography scan has shown no recurrence of the dentigerous cyst. Eighteen months later, there was no recurrence, and there has been complete resolution of the facial swelling.
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DISCUSSION
Dentigerous cysts are not usually aggressive. In this child, however, the lesion was quite aggressive, elevating the orbital floor and depressing the hard palate (Fig 2). This raises the issue of more serious diagnoses, including ameloblastoma and odontogenic keratocyst.
Ameloblastoma is rare in the pediatric age range, and in a classic review of 1036 cases of ameloblastoma, the average age was 38.9 years. Ameloblastoma occurs rarely in the maxilla (7% of pediatric cases), with most occurring in the mandible either at the angle of the mandible or the symphysis. The majority of these cases present radiologically as a dentigerous cyst, and it is necessary to examine the lining of the cyst to make the correct diagnosis. This is important, because the treatment is different, if controversial, in children, with some oral surgeons recommending radical resection to prevent recurrence.1 A unicystic ameloblastoma may present, like in our subject, but the histologic features did not support the diagnosis. Ameloblasts present were associated with enamel formation (Fig 5).
The odontogenic keratocyst is a result of a cystic change within the enamel organ before calcification, and expansion of this lesion results from rapid proliferation of the squamous epithelial lining and not from the accumulation of fluid as in a dentigerous cyst. This is an aggressive lesion, and recurrence is common.
In this patient, histologic examination confirmed the diagnosis of an odontoma, which is a radiolucent lesion consisting of multiple tiny, malformed, tooth-like structures in various stages of development. Usually this is a slow-growing lesion, but in our patient, it was associated with a follicular or dentigerous cyst, which arose from 1 of these tooth-like structures in the odontoma (Fig 6).
Dentigerous cysts in a child are extremely uncommon. A dentigerous cyst is a "benign expansive lesion derived from hydrostatic expansion of a dental follicle and surrounds the crown of an unerupted tooth."2 In our patient, the tooth remained close to the alveolar bone with the cyst extending upward. One usually expects to see the tooth at the superior part of the cyst as the cyst develops between the crown and the epithelium pushing the tooth upward (Fig 3). The typical dentigerous cyst arises from the enamel organ after amelogenesis is finished and is a result of the accumulation of fluid between the crown and the enamel organ pushing the crown away from the alveolar bone. Dentigerous cysts are associated with unerupted teeth and are usually found by the dentist during routine dental radiology.
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12 years of age. Most are found in the mandible.3 Another series from Brazil reviewing 2356 oral biopsies of patients 14 years of age over a 15-year period revealed that 6.5% had dentigerous cysts.4 Dentigerous cysts, especially bilateral or multiple, have been reported in patients with basal cell nevus syndrome, mucopolysaccharidosis, and cleidocranial dysplasia; they have also been associated with cyclosporine use and calcium channel blockers.3 Treatment is always surgical, requiring excision and pathologic examination to rule out other more aggressive lesions.5,6
CONCLUSIONS
Our patient presented with a painless right facial swelling initially felt to be an acute sinusitis. Over a period of several weeks, the expanding lesion in the right maxillary sinus, with additional imaging and histologic examination, revealed itself to be a dentigerous or follicular cyst associated with an odontoma. Although dentigerous cysts are more often found in the mandible, they may occur, as in our patient, in the maxilla. Histologic examination of the cyst lining is essential to differentiate this relatively benign lesion from a more aggressive lesion, such as an ameloblastoma or an odontogenic keratocyst, both of which require aggressive resection to prevent recurrence. Most reports of dentigerous cysts are found in the surgical literature (dental, oral/facial, or otolaryngology), with no reports in the general pediatric literature. Our patient is a reminder to general pediatricians to include the dentigerous cyst in the differential diagnosis of painless facial swelling.
ACKNOWLEDGMENTS
I acknowledge the assistance of Dr Peter Chauvin, associate professor and director of the Division of Oral Diagnostic Sciences, Faculty of Dentistry, McGill University, for providing the histology slides and their descriptive text.
FOOTNOTES
Accepted Jun 24, 2007.
The author has indicated he has no financial relationships relevant to this article to disclose.
REFERENCES
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