Immunohistochemical Expression of Calretinin in Ameloblastoma, Adenomatoid Odontogenic Tumor, and Keratocystic Odontogenic Tumor: A Comparative Study

Differential Expression of Immunohistochemical Markers in Ameloblastoma & Ameloblastic Carcinoma: A Systematic Review and Meta-analysis of observational studies

Background

Differentiating between ameloblastoma (AB) and ameloblastic carcinoma (AC) is difficult, especially when AB has atypical cytological characteristics or an uncommon clinical history. This systematic review and meta-analysis aimed to elucidate the differential expression of immunohistochemical markers between AB and AC.

Methods

We conducted a thorough search of PUBMED and SCOPUS according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify cross-sectional studies that compared the expression of immunohistochemical markers in AB and AC. We used a random-effects model to analyze the risk ratios and their corresponding 95% confidence intervals (CIs). The quality of the included studies was assessed using the Newcastle-Ottawa scale. The Egger's test was used to assess publication bias.

Results

In total, 301 articles were identified. After excluding irrelevant titles and abstracts, 86 articles were selected for full-text review. We categorized the 41 markers into proliferative and non-proliferative markers. Among non-proliferative markers, nuclear markers were differentially expressed in AB and AC. SOX2 was the only marker that significantly differentiated AB and AC, with an RR of -0.19 (CI 0.10-0.36, I2=0).

Conclusion

The current evidence suggests the significance of SOX2 in differentiating between AB and AC, warranting prospective confirmation in well-defined extensive studies. We highlight the paucity of high-quality replicated studies of other markers in this field. Collaborative efforts with standardized techniques are necessary to generate clinically useful immunohistochemical markers.

Immunohistochemical expression of Ki-67 and Glypican-3 to distinguish aggressive from nonaggressive benign odontogenic tumors

Background

The benign neoplasms are normally slow growing, indolent with no invasive potential. However, there exist a few locally aggressive benign odontogenic tumors that have a tendency to invade and deform the surrounding structures. The exact reason for the aggressiveness of these benign neoplasms remained an enigma. Their biology and clinical expression can often be destructive and ominous. An appropriate treatment protocol needs to be followed to combat the high recurrence rate and aggressiveness of these entities. Aggressive and noniaggressive epithelial odontogenic tumors were analyzed immunohistochemically with Ki-67 and glypican 3 (GPC3).

Materials and Methods

Fifty-nine cases of tumors were divided into aggressive odontogenic tumors (20 solid ameloblastomas, four unicystic ameloblastoma, and 28 keratocystic odontogenic tumors) and nonaggressive odontogenic tumors (five adenomatoid odontogenic tumors and two calcifying cystic odontogenic itumors).

Results

Statistical analysis using Pearson correlation showed Ki-67 to be a better marker for differentiating aggressive from nonaggressive odontogenic tumor as compared to GPC3 (P < 0.001, highly significant), whereas among aggressive tumors, GPC3 turned out to be more useful as compared to Ki-67 (P < 0.001, highly significant).

Conclusion

The present study provides an insight into the different biological behavior of odontogenic tumors, which can thus be helpful in determining the therapy strategies for more aggressive odontogenic tumors.

The diagnostic utility of BRAF VE1 mutation-specific immunohistochemistry in ameloblastoma

Ameloblastoma is a benign, locally aggressive odontogenic neoplasm with variable solid and cystic morphology. On account of its histologic variety, diagnostically challenging cases can bear resemblance to odontogenic keratocyst/keratocystic odontogenic tumor (KCOT) or dentigerous cyst (DC). BRAF^V600E mutation has been reported to be specific for and frequent in ameloblastoma, and this study evaluated the usefulness of immunohistochemistry (IHC) using the BRAF VE1 mutant-specific antibody as a diagnostic adjunct in this setting. We investigated 46 ameloblastomas, 30 KCOTs, and 30 DCs. BRAF VE1 IHC was performed on all cases and allele-specific polymerase chain reaction (AS-PCR) for BRAF^V600E mutation was performed on 30 ameloblastomas and any IHC-positive KCOT/DC. BRAF VE1 IHC was positive in 31/37 (83.8%) mandibular ameloblastomas but not in any maxillary ameloblastomas (0/9), KCOT (0/30), or DC (0/30). Equivocal staining was seen in 1/37 (3.3%) mandibular ameloblastomas. Of the 30 ameloblastomas subjected to AS-PCR, BRAF^V600E mutation was identified in 19/23 (82.6%) mandibular ameloblastomas and 0/7 (0.0%) maxillary ameloblastomas. BRAF^V600E mutant ameloblastomas were positive by IHC in 18/19 (94.7%) cases and equivocal in 1/19 (5.3%) cases. All 11 (100.0%) BRAF-wild type ameloblastomas were negative by IHC. BRAF VE1 is an excellent tool for the diagnosis of mandibular ameloblastoma but of limited utility in the maxilla, where it less commonly occurs and where BRAF^V600E mutation is considerably less frequent.

A retrospective cohort study on predictors associated with skull base invasion of maxillary ameloblastomas

PURPOSE

To identify factors associated with skull base involvement (SBI) of maxillary ameloblastomas (MA).

METHODS

This retrospective cohort study was composed of MA patients treated during a 7-year period. Demographic, radiographic, and nine immunohistopathologic predictor variables were included. The outcome variable was presence of SBI (yes/no). Descriptive, bi- and multivariate statistics were computed, and P ≤ .05 in multivariate analyses was considered statistically significant.

RESULTS

The sample comprised 23 subjects (34.8% females; 21.7% with SBI) with a mean age of 50.3 ± 18.2 years. Candidate predictors of an SBI in MAs were 1) male gender, 2) a low Karnofsky Performance Status score (KPS), 3) multilocular radiolucency, 4) ill-defined margins, 5) cortical perforation, 6) inclusion of an unerupted tooth, 7) moderate to strong reactivity to p53, Ki-67, CD10, astrocyte elevated gene-1 (AEG-1) protein, carbonic anhydrase IX (CA IX), calretinin (calbindin2; CALB2), and BRAF-V600E, and 8) negative to low immunopositivity to α-smooth muscle actin (α-SMA) and syndecan-1 (CD138). However, multivariate analyses confirmed the significant associations of SBI with negative/low syndecan-1 reactivity (P = .003; adjusted odds ratio [OR_adj.], 4.04; 95% confidence interval [95% CI], -.89 to -.48; Pearson's Correlation Coefficient [r] = -.74) and with KPS (P = .003; OR_adj., 4.04; 95% CI, -.78 to -.17; r = -.54) only.

CONCLUSIONS

Our findings suggest an aggressive approach to MAs with negative to low syndecan-1 immunopositivity and/or in multi-morbid patients (who may have difficulty in access to health care). Otherwise, health care inequalities due to low KPS scores should be minimized or eliminated.

Expression of calretinin in odontogenic keratocysts and basal cell carcinomas: A study of sporadic and Gorlin-Goltz syndrome-related cases

Gorlin-Goltz syndrome (GGS), is an autosomal dominant inherited disorder related to germline mutation of PTCH1 gene, characterised by the presence of multiple developmental anomalies and tumours, mainly basal cell carcinomas (BCC) and odontogenic keratocysts (OKC). We analysed and compared the expression of calretinin in 16 sporadic OKCs, from 15 patients, and 12 syndromic OKCs from 11 patients; in 19 BCC's and 2 cutaneous keratocysts (CKC) belonging to 4 GGS patients, 15 sporadic BCCs and 3 steatocystomas (SC). Calretinin was negative in 10 of 12 syndromic OKCs, focally positive (<5% of cells) in 2; six sporadic OKCs were negative, 6 focally and 4 diffusely positive (p = .02, cases focally and diffusely positive vs. cases negative). All BCCs of 3 GGS patients were negative, the fourth patient presented two BCCs negative and 5 focally or diffusely positive; 7 sporadic BCCs were negative and 8 focally positive (p = NS). Two CKCs resulted negative in one GGS patient; 2 sporadic SCs were positive, and a third was negative. PTCH1 mutations produce an altered PTCH protein and an aberrant activation of Sonic hedgehog (SHH) pathway, leading to tumoral proliferation. It has been demonstrated that treatment of human foetal radial glia cells with SHH reduces, whereas the blockage of SHH increases calretinin expression. We found a lower expression of calretinin in syndromic OKCs compared to sporadic cases. Although calretinin's value in differential diagnosis between sporadic and syndromic tumours appears not crucial, our results shed light on the possible link between SHH dysfunction and calretinin expression in GGS-related tumours.

Conservative management is effective in unicystic ameloblastoma occurring from the neonatal period: A case report and a literature review

Unicystic ameloblastoma (UA), a benign odontogenic tumor of the jaw, represents less than a third of all ameloblastomas and seems less aggressive than other types of ameloblastoma. We present here the first case of UA that developed prenatally and was successfully managed in the early neonatal period with marsupialization and curettage performed carefully to avoid injury to the tooth germ. BRAF and SMO mutations were not detected. After 2 years of follow-up, complete reossification and normal eruption of deciduous teeth were noted, and there was no recurrence of UA. We recommend conservative treatment of UA in the pediatric population to avoid loss of and/or injury to the tooth germ, provided close follow-up is carried out all through the individual's growth for early detection of potential recurrences, growth impairments, or tooth eruption disorders. The intratumoral somatic mutational status of BRAF, SMO, RAS family, and FGFR2 may help determine personalized targeted treatment, particularly in case of recurrence.

Calretinin expression in odontogenic cysts and odontogenic tumors and the possible role of calretinin in pathogenesis of ameloblastoma

Introduction:

Histopathological diagnosis of odontogenic cysts and tumors is a task mostly accomplished with hematoxylin and eosin staining. However, the use of additional diagnostic modalities such as immunohistochemistry may be necessary in histologically similar lesions. The reports of studies which have used calretinin as an immunohistochemical marker for ameloblastoma have been conflicting.

Aim:

The aim of the study was to evaluate the use of calretinin as a specific diagnostic marker for ameloblastoma and observe its expression in odontogenic cysts and other odontogenic tumors.

Materials and Methods:

Formalin-fixed, paraffin-embedded sections were taken from the archives which included 15 cases each of dentigerous cyst, radicular cyst, odontogenic keratocyst and ameloblastoma five cases of adenomatoid odontogenic tumor and three cases of ameloblastic carcinoma. Immunohistochemistry was done with calretinin antibody.

Results:

All ameloblastomas were positive for calretinin, whereas no other tumor or cyst showed positivity. Differences in proportion of calretinin expression were statistically significant with P = 0.000.

Conclusion:

Calretinin can be considered as a specific marker for ameloblastomas.

Glypican-3 distinguishes aggressive from non-aggressive odontogenic tumors: a preliminary study

BACKGROUND

Glypican-3 is a cell surface proteoglycan that is found in embrionary tissues, and there are no studies investigating this protein in odontogenic tumor. Thus, the aim of this study was to investigate glypican-3 in a series of aggressive and non-aggressive odontogenic tumors.

METHODS

Fifty-nine cases of tumors were divided into aggressive odontogenic tumors (20 solid ameloblastomas, four unicystic ameloblastoma, 28 KOTs including five associated with Gorlin-Goltz syndrome) and non-aggressive odontogenic tumors (five adenomatoid odontogenic tumors and two calcifying cystic odontogenic tumors) and analyzed for glypican-3 using immunohistochemistry.

RESULTS

Glypican-3 was observed in seven solid ameloblastoma and eighteen keratocystic odontogenic tumors including three of the five syndromic cases, but there was no significant difference between syndromic and sporadic cases (P > 0.05; Fisher's exact Test). All cases of unicystic ameloblastoma (n = 4), adenomatoid odontogenic tumor (n = 5), and calcifying cystic odontogenic tumor (n = 2) were negative.

CONCLUSIONS

This provided insights into the presence of glypican-3 in odontogenic tumors. This protein distinguished aggressive from non-aggressive odontogenic tumors.

Primordial Odontogenic Cyst with Induction Phenomenon (Zonal Fibroblastic Hypercellularity) and Dentinoid Material Versus Archegonous Cystic Odontoma: You Choose!

The most recent A.F.I.P. fascicle defines primordial odontogenic cyst (POC) as a distinct, nonkeratinized, odontogenic cyst of "undetermined origin" forming in the place of a developing normal or supernumerary tooth. However, the majority of examples reported in the literature under this term represent odontogenic keratocysts (keratocystic odontogenic tumors). In addition, there are rare reported cases of cystic odontomas. An 18-year-old Caucasian male presented with a unilocular mandibular radiolucent lesion in the place of a congenitally missing molar. Histologically, it featured nonkeratinizing, thin stratified squamous epithelial lining with areas of spongiosis and foci of vacuolization of individual basal cells without significant nuclear palisading. Focally, budding of the basal cell layer was identified. A zone of increased cellularity featuring induction-type fibroblasts was present subepithelially as well as dentinoid deposits with odontogenic epithelial nests. Immunohistochemically, the epithelial lining was negative for calretinin and the induction-like zone negative for S100 protein, smooth muscle actin, and CD34. The case was externally reviewed by five oral pathologists who provided various diagnostic interpretations including primordial cyst, odontogenic cyst not otherwise specified (NOS), cyst with ameloblastic changes, and unicystic ameloblastoma. At that time, a final diagnosis of odontogenic cyst NOS was rendered with a comment that it may represent a true example of POC or a cystic odontoma. The lesion has not recurred within a 13 year follow-up period after initial excision. An unusual cystic lesion is presented that may represent a true example of POC with dentinoid formation or an archegonous cystic odontoma.