Clinicopathological and cell proliferation evaluation of ameloblastomas and keratocystic odontogenic tumors: a 10 year retrospective study

Abstract

Odontogenic tumors (OTs) are important lesions of the gnathic bones due to their clinicopathological heterogeneity and variable biological behavior; therefore, epidemiological studies are needed to outline the incidence and behavior of these tumors. To evaluate the incidence and epidemiological profile of ameloblastoma (AMB) and keratocystic odontogenic tumor (KCOT) from an oral pathology service, and correlate morphological findings of these tumors with the immunoexpression of a cellular proliferation marker (Ki-67), a retrospective study (2002-2012) was conducted to characterize demographic, clinical, radiological, and morphological data of AMBs and KCOTs. Then, a representative sample composed of 49 cases of each tumor was selected to perform immunohistochemical (IHC) analysis of Ki-67 through the streptavidin biotin peroxidase technique. For statistical analysis, we used Fisher's exact test (p < 0.05). A total of 279 OTs were found in the service, in which 91 (32.6%) were AMB and 98 (35 %) were KCOT. Most cases occurred in white women, and the average age of patients with AMB and KCOT was 32 and 33 years, respectively. The maxilla-mandible ratio was 1:6 and 1:3.6 for AMB and KCOT, respectively. Regarding IHC analysis, AMB and KCOT had similar levels of cellular proliferation. However, KCOTs with intense inflammation showed higher Ki-67 expression (p < 0.001). Recurrent cases had similar Ki-67 immunoexpression. The demographic profile of the studied tumors corroborates with data reported in the literature, and the levels of cellular proliferation were similar in both tumors, although the inflammation seems to induce a differential proliferative behavior in KCOT.

Differential expression of nicotinamide N‐methyltransferase in primary and recurrent ameloblastomas and odontogenic keratocysts

“…20 Previous studies reported a low Ki-67 expression in odontogenic cyst and neoplasms. 21 Furthermore, data reported in literature seem to demonstrate that Ki-67 expression does not differ between OKC and AM, while other odontogenic cysts display low Ki-67 levels. 21,22 Another study found no differences in Ki-67 expression between primary and recurrent OKCs, suggesting that incomplete removal, rather than intrinsic growth rate, was likely to be responsible for recurrences.…”

“…21 Furthermore, data reported in literature seem to demonstrate that Ki-67 expression does not differ between OKC and AM, while other odontogenic cysts display low Ki-67 levels. 21,22 Another study found no differences in Ki-67 expression between primary and recurrent OKCs, suggesting that incomplete removal, rather than intrinsic growth rate, was likely to be responsible for recurrences. 22 In the present study, no differences were found in Ki-67 expression between primary and recurrent odontogenic lesions, confirming what is reported in literature about the limited usefulness of this marker in OKC and AM (Figure 3).…”

“…The nuclear protein Ki‐67 is a well‐known cellular marker strictly associated with cell proliferation . Previous studies reported a low Ki‐67 expression in odontogenic cyst and neoplasms . Furthermore, data reported in literature seem to demonstrate that Ki‐67 expression does not differ between OKC and AM, while other odontogenic cysts display low Ki‐67 levels .…”

The recurrence of odontogenic keratocysts in pediatric patients is associated with clinical findings of Gorlin-Goltz Syndrome

“…Of all odontogenic cysts, OKC represents about 6 to 25.7% and appears to be more frequent in males with a peak incidence of 20-30 years of age. This lesion deserves differential considerations due to its clinical presentation, since it presents invasive-infiltrative growth, expanding in great proportions, causing considerable bone destruction usually before any symptoms (5,8,(17)(18)(19).…”

“…The basal layer is cuboidal or columnar with palisading (2-7). Treatment may be conservative or aggressive, but with lesions involving permanent non-erupted teeth in children and adolescents a less mutilating approach is recommended (3,7,8). Most OKC appears as an isolated solitary lesion.…”