Comparison of Immunohistochemistry and DNA Sequencing for BRAF V600E Mutation Detection in Mandibular Ameloblastomas.

This study aimed to investigate the presence of BRAF V600E mutation in mandibular ameloblastoma by comparing the results of molecular detection and immunohistochemical analysis. A 128 cases of mandibular ameloblastoma and 30 cases of dentigerous cyst (control group) were selected for analysis. Detection of BRAF V600E mutation was performed with immunohistochemistry (IHC) and polymerase chain reaction techniques. Clinico-pathologic data were collected in order to investigate possible associations with the mutation. Of the 128 cases submitted to IHC, 81.2% (108 cases) showed positivity for anti-BRAF V600E antibody, whereas 24 were negative (18.8%). Molecular analysis of the BRAF V600E mutation by polymerase chain reaction was possible in 116 cases due to DNA quality. Of these cases, 96 were positive (82.8%) and 20 negative (17.2%). All cases of dentigerous cyst were negative for BRAF V600E mutation in both techniques. Considering the sequencing as a gold standard method, the receiver operating characteristics curve analysis showed sensitivity of 0.99 and specificity of 1 (area under the curve=0.995, standard error=0.006; P<0.001; 95% confidence interval=0.983 to 1). We also tested the agreement between the techniques by using the Cohen's κ coefficient, with κ being 0.97 (P<0.001). IHC is a reliable test for identifying the BRAF V600E mutation in ameloblastomas, presenting advantages such as being more frequently used in surgical pathology laboratories and requiring fewer critical steps for paraffin-embedded tissue compared with molecular biology techniques.

Central angioleiomyoma of the mandible: A rare entity.

The leiomyoma is a benign smooth-muscle neoplasm commonly found in the female genital tract, gastrointestinal tract, or skin. Leiomyomas of the oral cavity are unusual. Oral leiomyomas are uncommon due to the paucity of the smooth muscle in the mouth (except in blood vessels) and thus the involvement of jaw bones is extremely rare. Leiomyomas have been classified as solid angiomyoma, angioleiomyoma (vascular leiomyoma), and epithelioid variants. Angioleiomyomas are benign mesenchymal tumors derived from smooth muscle, which rarely occur in the oral cavity. Malignant transformation probably does not occur but careful histopathologic examination is still necessary to differentiate these benign lesions from their malignant counterparts due to different prognosis. Although uncommon in the maxilla and mandible, they should be included in the differential diagnosis of radiolucent lesions of jaw bones. An extensive search of literature was carried out on the Medline-PubMed and Google Scholar database using the keywords such as leiomyoma, angioleiomyoma, jaw bones, maxilla, mandible, intra-osseous to thoroughly search and collect all the reported cases of intraosseous leiomyoma (but our search was not limited to these terms only). To the best of our knowledge, only 23 cases of intraosseous leiomyomas have been reported so far in the jaw bones, among which only 8 belonged to angioleiomyomas. Herein, we report the 9th case of intraosseous angioleiomyoma, one of the variants of leiomyoma and overall 24th intraosseous leiomyoma in a 6-year-old female child, together with conventional histopathologic and immunohistochemical findings.

Immunohistochemical Investigation of Predictive Biomarkers for Mandibular Bone Invasion in Oral Squamous Cell Carcinoma.

The accurate preoperative determination of the extent of mandibular resection remains a challenge for the surgeons. The purpose of the present study was to immunohistochemically investigate predictive markers for histological bone invasion of oral squamous cell carcinoma (OSCC). The medical records of primary OSCC patients with mandibular bone contact in preoperative computed tomography scans between January 2003 and December 2017 were retrospectively reviewed and an immunohistochemical investigation was performed. Forty-five OSCC patients with mandibular bone contact radiographically were included in this study. Histopathologically, infiltrative bone invasion was observed in 19 patients (42.2%) and compressive bone invasion in 15 (33.3%). A correlation was noted between the histological pattern of bone invasion and mode of invasion (chi-squared test, p < 0.05). At the tumor surface, a correlation was observed between the expression of IL-6 and bone invasion (the Wilcoxon test, p < 0.05), although the expression was so weak. At the bone contact area, the expression of both ɑ-SMA and OPG correlated with infiltrative bone invasion (ɑ-SMA; the Wilcoxon test, p < 0.05, OPG; p < 0.05). These results suggest that predictive markers for aggressive (infiltrative) bone invasion in OSCC patients with a higher mode of invasion are the expression of ɑ-SMA and OPG.

Sclerosing Epithelioid Fibrosarcoma of the Bone With Rare EWSR1-CREB3L3 Translocation Driving Upregulation of the PI3K/mTOR Signaling Pathway.

Sclerosing epithelioid fibrosarcoma (SEF) is an uncommon neoplasm that rarely presents in bone. It is characterized by epithelioid cells arranged in nests and single-file cords within a sclerotic stromal background which may mimic neoplastic bone. SEF harbors an EWSR1 translocation, which may complicate its distinction from Ewing sarcoma in cases with histomorphologic overlap. We present a diagnostically challenging case of SEF in the mandible of a 16-year-old girl. Our experience highlights the lack of specificity of traditional morphology and EWSR1 break-apart fluorescent in situ hybridization. Open-ended RNA-based fusion gene testing coupled with MUC4 immunohistochemistry aided the eventual diagnosis in this case. Herein, we report the third case of SEF with EWSR1-CREB3L3 translocation and show that this fusion leads to aberrant upregulation of the phosphoinositide 3-kinase/mammalian target of rapamycin signaling pathway in heterologous cell models.

Clinicopathologic study on a rare variant of ameloblastoma with basal cell features.

OBJECTIVES: To investigate the clinical features, pathologic manifestations, and biologic behaviors of a variant of ameloblastoma with basal cell features (AM-BC). MATERIALS AND METHODS: Following retrospective review of the clinical and pathological data of six cases of AM-BC, we described their histological and immunohistochemical (IHC) features and discussed the biologic behaviors, prognoses, pathogenesis, and clinical relevance of AM-BC. Direct sequencing of polymerase chain reaction products was also performed in all cases. RESULTS: The six cases of AM-BC involved four women and two men, aged 22-82 years. Four lesions occurred in the maxilla and two in the mandible. Histologically, the basal cells tended to be arranged as unequally sized follicles, strands, or cords of odontogenic epithelium in the connective tissue stroma. Little or no stellate reticulum was present in the central portion of the nest. Expression of CKs was consistent with other histological variants of ameloblastoma (AM), but AM-BC had significantly higher p53 and Ki-67 (p < 0.05) labeling indices than other histological variants of AM. Two patients had BRAF gene mutations. CONCLUSION: Ameloblastoma with basal cell features is a very rare variant of AM. Our study showed the differences and relationships that exist between AM-BC and other variants of AM, which could enhance understanding of AM-BC.

EGFR is not amplified in ameloblastoma.

OBJECTIVE: The aim of this study was to investigate alterations in the EGFR gene and its protein expression for a better understanding of the biologic behavior of ameloblastoma. STUDY DESIGN: Twenty-five samples of ameloblastoma were selected, and dual-color fluorescence in situ hybridization assay was performed. The results of the assay and immunohistochemistry reaction for EGFR and Ki67 were associated with clinicopathologic features and recurrence. RESULTS: All analyzed cases presented disomy without any gene polysomy or amplification. With regard to EGFR immunoexpression, 3 cases (12%) were considered negative, and 22 (88%) were positive, of which 13 (52%) were weak and 9 (36%) were strong. All samples presented low positivity for Ki67. There was no association between EGFR expression and clinicopathologic features or recurrence (P > .05). In some cases, EGFR immunoexpression was observed without gene amplification. CONCLUSIONS: Ameloblastoma development, progression, or recurrence does not appear to be related to EGFR amplification or polysomy.

Expression of TP53 and IL-1α in unicystic ameloblastoma predicts the efficacy of marsupialization treatment.

In this study, we evaluated the effects of marsupialization in treating unicystic ameloblastoma (UA) and investigated the relationship between TP53 and interleukin 1 α (IL-1α) expression and the clinical outcome of UA treated with marsupialization.Consecutive patients treated with marsupialization and curettage at Shanghai Ninth People's Hospital were included. According to the unified standard, 48 patients were included in this study. Of these, 20 showed a good response, 10 a partial response, and 18 no response, based on the outcome of the marsupialization procedure. The expression of proteins TP53 and IL-1α was detected with immunohistochemistry (IHC). The clinical and pathological characteristics of the patients were analyzed.Analysis of the clinical and pathological characteristics showed that the effects of marsupialization treatment were significantly associated with lesion location (P < .001) and tumor diameter (P = .01). IHC showed that TP53 expression was significantly higher in the good-response group than in the partial- or no-response group (P = .02), and IL-1α expression was significantly higher in the good-response group than in the partial- and no-response groups (P = .03).Marsupialization is an effective preliminary procedure for treating UA before curettage and peripheral ostectomy. The expression of the TP53 and IL-1α proteins correlates directly with the outcome of UA treated with marsupialization.

Differential expression of the epithelial mesenchymal transition factors Snail, Slug, Twist, TGF-ß, and E-cadherin in ameloblastoma.

Epithelial mesenchymal transition (EMT), the transition of epithelial cells into motile mesenchymal cells, plays an important role in embryogenesis, cancer invasion, and metastasis. Ameloblastomas are common epithelial odontogenic tumors, occurring exclusively in the mandible with locally invasive growth. Thirty-seven ameloblastoma cases were evaluated for the involvement of EMT by immunohistochemical staining and western blotting using antibodies against Slug, Snail, Twist, TGF-ß, and E-cadherin. Double immunostaining was also performed. Slug and TGF-ß were expressed in the nuclei of peripheral and stellate reticulum cells of ameloblastoma nests. Twenty cases of Snail, 36 of Slug, 8 of Twist, and 19 of TGF-ß showed strong expression in tumor cells in follicular and plexiform patterns. Expression of Slug and TGF-ß increased in regions where the expression of E-cadherin was reduced. EMT was found to be associated with the local invasive growth of ameloblastoma. These data suggest that reduced expression of E-cadherin and over-expression of Slug, Snail, and TGF-ß induce EMT. Given that ameloblastomas are characterized by local invasiveness, EMT might be related to their development. Thus, strong expression of Slug and TGF-ß and reduced expression of E-cadherin might be related to the local invasiveness of ameloblastoma.

Tumor-induced Osteomalacia in a 3-Year-Old With Unresectable Central Giant Cell Lesions.

Tumor-induced osteomalacia (TIO) is a rare cause of hypophosphatemia involving overproduction of fibroblast growth factor 23. TIO has been described largely in adults with small mesenchymal tumors. We report a case of TIO in a child who presented with knee pain and radiographic findings concerning for rickets, and was found to have maxillomandibular giant cell lesions. The patient was treated with oral phosphorus and calcitriol, surgical debulking, and intralesional corticosteroids, which resulted in tumor regression and normalization of serum fibroblast growth factor 23 and phosphorus. This case illustrates the occurrence of this rare paraneoplastic syndrome in children and adds to our knowledge about clinical manifestations and pathologic findings associated with pediatric TIO.

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

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.

Expression of CD90 and P75NTR stem cell markers in ameloblastomas: a possible role in their biological behavior.

Multicystic and unicystic ameloblastomas are benign odontogenic tumors that present distinct biological behavior. The investigation of stem cells has become an important branch of tumor biology, with several studies addressing the possible role of these cells in tumor growth, angiogenesis, progression, infiltration and invasiveness. This study evaluated the immunohistochemical expression of CD90(Thy-1) and P75NTR stem cell markers in multicystic and unicystic ameloblastomas. Seventeen (17) samples of ameloblastomas (multicystic, n = 10; unicystic, n = 7) were submitted to immunohistochemical reactions and graded semi-quantitatively. The Kolmogorov-Smirnov test was used to verify possible differences in CD90 and P75NTR expressions between multicystic and unicystic ameloblastomas (p < 0.05). CD90 immunostaining was observed in all multicystic ameloblastoma specimens (n = 10), in the cytoplasm of the fibroblasts and vascular endothelial cells of the tumor stroma, near the neoplastic odontogenic epithelia. The staining of stromal CD90 was significantly higher in multicystic than in unicystic ameloblastomas (p = 0.003). Nuclear P75NTR immunostaining was observed in all ameloblastoma specimens. A significant difference was seen in the epithelial staining of P75NTR between multicystic and unicystic types (p = 0.007). The increased expression of CD90 and P75NTR found in multicystic ameloblastomas suggests a behavioral biological difference between multicystic and unicystic ameloblastomas, as well as a difference in ameloblastoma development.

Survivin, cyclin D1, and p21hras in keratocystic odontogenic tumors before and after decompression.

OBJECTIVES: The aim of this study was to investigate survivin, cyclin D1, and p21hras expression in keratocystic odontogenic tumors before and after decompression, as well as in pericoronal follicles. A potential correlation between the expression levels of these proteins was also investigated. MATERIALS AND METHODS: We analyzed eighteen keratocystic tumors treated by decompression and subsequent enucleation along with seven pericoronal follicles using immunohistochemistry. RESULTS: Keratocystic tumor samples, both before and after decompression, were positive for each of the investigated proteins. In pericoronal follicles, survivin exhibited cytoplasmic staining in contrast to nuclear staining in keratocystic tumors. Cyclin D1 expression was negative in pericoronal follicles, and p21hras expression was similar in both groups. Survivin showed significantly higher expression after decompression, while cyclin D1 and p21hras remained unchanged (P = 0.039, P = 0.255, P = 0.913, respectively). There was no correlation between these proteins neither before nor after decompression. CONCLUSIONS: Within the limits of the study, we can conclude that following decompression, keratocystic odontogenic tumors preserve distinct immunohistochemical profiles of cyclin D1 and p21hras expression, despite substantial reduction in size of the lesions. Significant increase of survivin expression after decompression might be attributed to higher level of epithelial proliferation caused by this procedure.

Expression of CD90 and P75NTR stem cell markers in ameloblastomas: a possible role in their biological behavior

Abstract Multicystic and unicystic ameloblastomas are benign odontogenic tumors that present distinct biological behavior. The investigation of stem cells has become an important branch of tumor biology, with several studies addressing the possible role of these cells in tumor growth, angiogenesis, progression, infiltration and invasiveness. This study evaluated the immunohistochemical expression of CD90(Thy-1) and P75NTR stem cell markers in multicystic and unicystic ameloblastomas. Seventeen (17) samples of ameloblastomas (multicystic, n = 10; unicystic, n = 7) were submitted to immunohistochemical reactions and graded semi-quantitatively. The Kolmogorov-Smirnov test was used to verify possible differences in CD90 and P75NTR expressions between multicystic and unicystic ameloblastomas (p < 0.05). CD90 immunostaining was observed in all multicystic ameloblastoma specimens (n = 10), in the cytoplasm of the fibroblasts and vascular endothelial cells of the tumor stroma, near the neoplastic odontogenic epithelia. The staining of stromal CD90 was significantly higher in multicystic than in unicystic ameloblastomas (p = 0.003). Nuclear P75NTR immunostaining was observed in all ameloblastoma specimens. A significant difference was seen in the epithelial staining of P75NTR between multicystic and unicystic types (p = 0.007). The increased expression of CD90 and P75NTR found in multicystic ameloblastomas suggests a behavioral biological difference between multicystic and unicystic ameloblastomas, as well as a difference in ameloblastoma development.

Desmoplastic fibroma of the mandible: a series of three cases and review of literature.

The desmoplastic fibroma (DF) is a rare, fibroblastic lesion of bone that histologically resembles the desmoid tumor of soft tissue. Although classified as benign, it frequently demonstrates aggressive behavior, often causing tooth mobility, extensive bone destruction, and has a moderate to high recurrence rate. We present three cases of DF in the mandible: the first in a 13 year old female involving the mandibular body in the region of teeth #s 27-#28, the second in a 57 year old female with a lesion apical to tooth #30, and the third in a 20-year-old female involving the left posterior mandible. Clinical, histologic, immunohistochemical (IHC) and radiographic features of this rare neoplasm are discussed. The challenges encountered in establishing an accurate diagnosis due to significant microscopic overlap with other spindle cell lesions are also detailed. Additionally, the findings of IHC stains including vimentin, smooth muscle actin, S-100 protein, ß-catenin, HHF-35 and proliferation marker, Ki-67 on 3 cases are reported. The potential for misdiagnosis is high, especially in early lesions, since immunohistochemistry has been reported in literature to be inconsistent when differentiating DFs from other spindle cell lesions. A comparative review of DF and similar entities in the jaws with current considerations in treatment and prognosis is presented.

Mandibular swelling in a 5-year-old child--mandibular myofibroma.

A 5-year-old girl of African descent presented with a history of progressive painless swelling on the right side of the jaw since the past 2-3 months. Orthopantomogram showed a radiolucent lesion near the angle of the mandible. Subsequent CT scan revealed a 2 cm×2 cm radiolucent lesion with intense periosteal reaction surrounding the lesion and destruction of the overlying cortex. Radiological perplexity aroused regarding the possibility of eosinophilic granuloma or some other malignant lesion. Incisional biopsy performed and microscopy showed spindle cell tumor. Immunohistochemistry confirmed it as myofibroma. Myofibroma is a rare benign tumour involving mesenchyme. Involvement of the mandible is rare. Radiological presentation with strong periosteal reaction is a rarity and has rarely been reported in the medical literature. We conclude that intraosseous myofibroma can sometimes have strong periosteal reaction and careful radiological evaluation is a prerequisite for accurate diagnosis and to avoid unnecessary aggressive therapy.

Granular cell ameloblastoma: enigmatic cells in an unusual neoplasm.

An unusual granular variant of ameloblastoma presenting as a mandibular mass in a 43-year-old woman is described. These visually striking tumors display unusual and inconsistent immunohistochemical staining patterns although differential diagnosis from other granular cell lesions of the head and neck is usually not problematic.

Delayed metastasis to the mandible of esophageal adenocarcinoma.

Around 1 % of oral cancers are metastases from distant sites. Tumor metastases to the jaw bones are uncommon and are most likely to arise from primary lung, breast, prostate or kidney tumors. Jaw bone metastases from a primary esophageal adenocarcinoma are especially rare, with only 7 reports published in the literature. Here, we describe a case of a 69 year-old male patient where 7 years elapsed between the diagnosis and successful treatment of a poorly differentiated, stage pT2N0 primary esophageal adenocarcinoma and re-presentation with jaw pain due to a metastatic mandibular deposit. The morphological appearance of the metastasis and immunohistochemical positivity with CK20, CK7 and CDX2 strongly supported an adenocarcinoma of upper gastrointestinal tract origin. This case is of particular interest as there is an unusually long time between the detection of the primary esophageal adenocarcinoma and diagnosis of metastatic disease. The longest period of time we have found for this in the literature is 9 months, although it is also reported that some oral metastases may appear more than 10 years following the primary tumor diagnosis.

Expression of proliferative markers in ameloblastomas and malignant odontogenic tumors.

OBJECTIVE: To compare the proliferative activity in ameloblastoma and malignant odontogenic tumors, as assessed by Ki-67 immunostaining and determine whether expression of substance P (SP) and NK-1 receptor (NK-1R) is related to cell proliferation in these tumors. MATERIALS AND METHODS: Immunohistochemistry was used to evaluate protein expression in 44 benign and malignant odontogenic tumors from 39 patients. Immunohistochemistry was performed with anti-SP, anti-NK-1R, and anti-Ki-67 monoclonal antibodies, and the clinical and pathological data of the patients with odontogenic tumor were evaluated. RESULTS: Expression of Ki-67 in malignant odontogenic tumors was significantly higher than in ameloblastomas (P < 0.001), and the expression level was associated with higher expression of NK-1R. Among the ameloblastomas, there was significantly higher expression of Ki-67 in peripheral ameloblastic-like cells (3.3 ± 4.1) than in stellate reticulum-like cells (2.6 ± 3.7) (P = 0.04). In the majority of tissue locations of the malignant tumors, expression of SP and NK-1R was positively correlated with higher expression of Ki-67. CONCLUSION: These findings show that the expression level of Ki-67 in ameloblastomas was positively correlated with the rate of growth of odontogenic tumors. Overexpression of NK-1R complex in malignant odontogenic tumors could be part of the trigger stimulus that results in higher proliferative activity of the tumor.