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Case of the Month Archives

COM Feb 2020 Diagnosis

Large multilocular, expansile radiolucency, anterior mandible

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This is a 52-year-old female who presented to her dentist with a new onset of left lower jaw swelling associated with left lower lip and chin paresthesia.

Case of the Month Summary

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The site in the anterior mandible and the radiographic findings of a well-demarcated and expansile radiolucency with a hint of multilocular appearance are all features consistent with the clinical and radiographic presentation of GOC. The age of the patient is also consistent since the mean age for GOC is around 50 years old. The gender is less consistent because GOC is slightly more common in males. The histology of this lesion is not that of GOC.

Glandular odontogenic cyst (GOC) is a developmental cyst of tooth origin characterized by unusual lining epithelium and occasional aggressive behavior. The uniqueness of this cyst lies in its histology. The lining epithelium is stratified squamous in type, but covered by cuboidal or columnar cells (sometimes ciliated) interspersed with microcytic spaces simulating salivary gland ducts, giving rise to the name “glandular.” It is a rare cyst and, though mostly inert, it can sometimes be aggressive in behavior. Because it occurs in association with teeth, it is believed to be of tooth origin. Therefore, the name “glandular” is misleading. Glandular odontogenic cyst is more common in adults of an average age of 49, with a slight male predominance. It has, however, been reported in all age ranges, including teenagers. It occurs three times more commonly in the mandible than in the maxilla, especially in the anterior mandible. Radiographically, they tend to present as unilocular and, less commonly, as multilocular radiolucencies. Multilocular GOCs tend to recur more than unilocular ones. These lesions grow to large sizes in the majority of cases and can perforate bone in a manner similar to the behavior of odontogenic keratocyst, a known aggressive cyst of tooth origin. Like OKCs, GOCs can be aggressive in bone perforation and recurrence rate. The recurrence rate ranges between 21-55%. Enucleation and curettage alone carry a high recurrence rate of 25%. Marsupialization has been successfully used.

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The patient’s gender, her age, and the radiographic findings of a well-demarcated, expansile radiolucent bony lesion are all features consistent with those of brown tumor of hyperparathyroidism. The histology was that of central giant cell granuloma, which is indistinguishable from that of hyperparathyroidism. The lab test for the parathyroid hormone level was performed and was high, rendering a diagnosis of primary hyperparathyroidism. The patient’s parathyroid glands are being evaluated.

Hyperparathyroidism is the result of excessive production of parathyroid hormone (PTH), which is needed for calcium release. When too much PTH is released, there will be generalized bone resorption, especially in the small bones such as the jaws and the small finger bones. There are three types of hyperparathyroidism: primary, secondary and tertiary. We will focus on the primary subtype. Primary hyperparathyroidism is usually associated with parathyroid adenoma, but possibly parathyroid hyperplasia and rarely adenocarcinoma. Primary hyperparathyroidism is three times more common in women and is more common in middle-aged females. It may produce multiple bone lesions indistinguishable from central giant cell granuloma. They are called ‘brown tumor’ because of the chocolate brown color of the soft tissue within the bone. Patients with hyperparathyroidism complain of “stones, bones, moans and groans.” The laboratory tests show increased levels of PTH hormone, which this patient had.

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The well-demarcated expansile radiolucency with a hint of multilocular appearance is typical of the radiographic presentation of solid ameloblastoma. The patient’s age fits within the spectrum of typical occurrence, though it is higher than the mean age of 33 years. Solid ameloblastoma occurs equally in males and females. The site is not consistent with this condition because the posterior mandible is the most common site. The histology is not consistent with solid ameloblastoma.

Solid ameloblastoma is one of the most common benign neoplasms of odontogenic origin. It accounts for 11% of all odontogenic neoplasms. It is a slow-growing, persistent, and locally aggressive neoplasm of odontogenic epithelial origin. It affects a wide age range but is mostly a disease of adults with an average age of 33 and equal sex distribution. Reports from Africa and India show a male predilection; it also has a predilection for occurrence in black patients.

About 85% of ameloblastomas occur in the posterior mandible; most of these occur in the molar-ramus area. Some occur in the anterior mandible, but sporadically. Solid ameloblastoma is characteristically expansile, radiolucent and multilocular in nature. Solid ameloblastoma, if not treated, can reach very large sizes, causing facial disfigurement. It can loosen, displace and resorb adjacent teeth and perforate bone. With the exception of jaw expansion, it is usually asymptomatic unless infected, in which case it can be mildly painful. Paresthesia and anesthesia are very rare, unless the lesion is very large in size. It has a high tendency for recurrence if not treated appropriately with clean margins.

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Generally, the site and the multilocular and expansile radiolucency argue against a diagnosis of OKC since OKC more commonly occurs in the posterior mandible and ramus. The age of this patient is on the older end of the spectrum of OKC and the gender is not consistent since OKCs tend to be slightly more common in males. The histology is not consistent with OKC.

Odontogenic keratocyst is an aggressive cyst known for its rapid growth and its tendency to invade the adjacent tissues and perforate bone. It has a high recurrence rate and is associated with bifid rib basal cell nevus syndrome. The majority of patients are in the age ranges of 10-40 years of age with a wide age range of 5-92. The distribution between sexes varies from equal distribution to a male-to-female ratio of 1.6:1, except in children. OKC predominantly affects Caucasian populations chiefly of Northern European descent. Almost 70% of OKCs occur in the angle of the mandible and ramus. Radiographically, OKCs present predominantly as unilocular radiolucencies with well-defined, sclerotic or scalloped borders. They may also present as multilocular radiolucencies. The larger OKCs tend to expand bone, but mildly—obvious clinical expansion should be viewed with suspicion for a neoplasm. OKCs can also present as small and oval radiolucencies between teeth simulating a lateral periodontal cyst, in an area of an extracted tooth simulating a residual cyst, at the apex of a vital tooth mistaken for a periapical cyst, or in the anterior maxilla between the central incisors simulating an incisive canal cyst. OKCs grow to sizes larger than any other odontogenic cysts. They usually penetrate the bone rather than expand it and grow in an anterior to posterior direction. Despite this aggressive growth, they often remain asymptomatic, thus growing to large sizes and hollowing the bone. They have a recurrence rate of 12% to 60%. Most cysts recur within the first three years while others may recur as late as after 26 years (this reviewer’s experience).

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