Serine protease inhibitors decrease metastasis in prostate, breast, and ovarian cancers

Targeted therapies for prostate, breast, and ovarian cancers are based on their activity against primary tumors rather than their anti-metastatic activity. Consequently, there is an urgent need for new agents targeting the metastatic process. Emerging evidence correlates in vitro and in vivo cancer invasion and metastasis with increased activity of the proteases mesotrypsin (prostate and breast cancer) and kallikrein 6 (KLK6; ovarian cancer). Thus, mesotrypsin and KLK6 are attractive putative targets for therapeutic intervention. As potential therapeutics for advanced metastatic prostate, breast, and ovarian cancers, we report novel mesotrypsin- and KLK6-based therapies, based on our previously developed mutants of the human amyloid β-protein precursor Kunitz protease inhibitor domain (APPI). These mutants, designated APPI-3M (prostate and breast cancer) and APPI-4M (ovarian cancer), demonstrated significant accumulation in tumors and therapeutic efficacy in orthotopic preclinical models, with the advantages of long retention times in vivo, high affinity and favorable pharmacokinetic properties. The applicability of the APPIs, as a novel therapy and for imaging purposes, is supported by their good safety profile and their controlled and scalable manufacturability in bioreactors.

Functional binding of PD1 ligands predicts response to anti-PD1 treatment in patients with cancer

Accurate predictive biomarkers of response to immune checkpoint inhibitors (ICIs) are required for better stratifying patients with cancer to ICI treatments. Here, we present a new concept for a bioassay to predict the response to anti-PD1 therapies, which is based on measuring the binding functionality of PDL1 and PDL2 to their receptor, PD1. In detail, we developed a cell-based reporting system, called the immuno-checkpoint artificial reporter with overexpression of PD1 (IcAR-PD1) and evaluated the functionality of PDL1 and PDL2 binding in tumor cell lines, patient-derived xenografts, and fixed-tissue tumor samples obtained from patients with cancer. In a retrospective clinical study, we found that the functionality of PDL1 and PDL2 predicts response to anti-PD1 and that the functionality of PDL1 binding is a more effective predictor than PDL1 protein expression alone. Our findings suggest that assessing the functionality of ligand binding is superior to staining of protein expression for predicting response to ICIs.

Mutated HRAS Activates YAP1-AXL Signaling to Drive Metastasis of Head and Neck Cancer

The survival rate for patients with head and neck cancer (HNC) diagnosed with cervical lymph node (cLN) or distant metastasis is low. Genomic alterations in the HRAS oncogene are associated with advanced tumor stage and metastasis in HNC. Elucidation of the molecular mechanisms by which mutated HRAS (HRASmut) facilitates HNC metastasis could lead to improved treatment options for patients. Here, we examined metastasis driven by mutant HRAS in vitro and in vivo using HRASmut human HNC cell lines, patient-derived xenografts, and a novel HRASmut syngeneic model. Genetic and pharmacological manipulations indicated that HRASmut was sufficient to drive invasion in vitro and metastasis in vivo. Targeted proteomic analysis showed that HRASmut promoted AXL expression via suppressing the Hippo pathway and stabilizing YAP1 activity. Pharmacological blockade of HRAS signaling with the farnesyltransferase inhibitor tipifarnib activated the Hippo pathway and reduced the nuclear export of YAP1, thus suppressing YAP1-mediated AXL expression and metastasis. AXL was required for HRASmut cells to migrate and invade in vitro and to form regional cLN and lung metastases in vivo. In addition, AXL-depleted HRASmut tumors displayed reduced lymphatic and vascular angiogenesis in the primary tumor. Tipifarnib treatment also regulated AXL expression and attenuated VEGFA and VEGFC expression, thus regulating tumor-induced vascular formation and metastasis. Our results indicate that YAP1 and AXL are crucial factors for HRASmut-induced metastasis and that tipifarnib treatment can limit the metastasis of HNC tumors with HRAS mutations by enhancing YAP1 cytoplasmic sequestration and downregulating AXL expression.

SIGNIFICANCE

Mutant HRAS drives metastasis of head and neck cancer by switching off the Hippo pathway to activate the YAP1-AXL axis and to stimulate lymphovascular angiogenesis.

Voltage-Dependent Anion Channel 1 Expression in Oral Malignant and Premalignant Lesions

BACKGROUND

The voltage-dependent anion channel 1 protein (VDAC1) plays a role in cellular metabolism and survival. It was found to be down or upregulated (overexpressed) in different malignancies but it was never studied in application to oral lesions. The purpose of this study was to retrospectively evaluate the expression of VDAC1 in biopsies of oral premalignant, malignant, and malignancy-neutral lesions and to examine the possible correlations to their clinicopathological parameters.

MATERIALS AND METHODS

103 biopsies including 49 oral squamous cell carcinoma, 33 epithelial dysplasia, and 21 fibrous hyperplasia samples were immunohistochemically stained with anti-VDAC1 antibodies for semi-quantitative evaluation. The antibody detection was performed with 3,3'-diaminobenzidine (DAB). The clinicopathological information was examined for possible correlations with VDAC1.

RESULTS

VDAC1 expression was lower in oral squamous cell carcinoma 0.63 ± 0.40 and in oral epithelial dysplasia 0.61 ± 0.36 biopsies compared to fibrous hyperplasia biopsies 1.45 ± 0.28 (p < 0.01 for both; Kruskal-Wallis test).

CONCLUSION

Oral squamous cell carcinoma and epithelial dysplasia tissues demonstrated decreased VDAC1 protein expression if compared to fibrous hyperplasia samples, but were not different from each other, suggesting that the involvement of VDAC1 in oral carcinogenesis is an early stage event, regulating cells to live or die.

Efficacy of ultrasound shear wave elastography in the diagnosis of salivary gland tumors

PURPOSE

Diagnostic accuracy of fine-needle aspiration cytology (FNAC) as the ability to discriminate between the target condition and health in the evaluation of salivary gland tumors is not perfected yet and false-negative results are possible. The purpose of the present study was to measure and compare the diagnostic accuracy of FNAC performed with conventional B-mode ultrasound and ultrasound with shear wave elastography (SWE) FNAC navigation.

METHODS

The investigators implemented a single-blind randomized study (sealed envelope method). The study population was composed of all patients presenting for evaluation and management of suspected benign or malignant tumors of the major salivary glands between July 2013 and December 2020. The involvement of SWE navigation was the primary predictor variable affecting FNA targeting. The method involved analysis of redistribution of SWE values within the affected gland expressed in kilopascals (kPa) and the four-point ES1 (soft tissue) to ES4 (stiff) scoring. The primary outcome variable was the success in obtaining diagnostic tissue resulting in a histologically confirmed FNAC diagnosis and coded as yes/no. Age and sex of the patients and topographical locations of lesions were covariates. Descriptive and bivariate statistics were computed and the P value was set at .05.

RESULTS

The sample included 132 subjects (male/female 59/73; mean age 54 ± 11 years; 144 tumors). SWE + Group (n = 66) consisted of patients presurgically diagnosed with salivary tumors SWE-guided FNAC and SWE- Group (n = 66) was diagnosed with tumors by conventional ultrasound-(B-mode)-guided FNAC. The SWE-guided FNAC statistically significantly reduced the incidence of false-negative results (n = 0; P = .001) and nondiagnostic cases (n = 3 SWE FNAC vs n = 7 B-mode US FNAC; P = .04). For SWE + Group, the FNAC diagnosis was confirmed by postsurgical histology in 95.5% with 91.0% sensitivity (confidence interval [CI] 0.62 to 0.97) and 84.4% specificity (CI 0.58 to 0.96). For SWE- Group, 81.8% confirmation was obtained (P = .05) with 82.3% sensitivity (CI 0.54 to 0.90) and 74.0% specificity.

CONCLUSION

SWE can increase success in obtaining diagnostic tissue when used for FNAC navigation purposes. We suggest combining both SWE and standard B-mode US methods when the FNAC procedure is performed.

MEK1/2 inhibition transiently alters the tumor immune microenvironment to enhance immunotherapy efficacy against head and neck cancer

Background

Although the mitogen-activated protein kinases (MAPK) pathway is hyperactive in head and neck cancer (HNC), inhibition of MEK1/2 in HNC patients has not shown clinically meaningful activity. Therefore, we aimed to characterize the effect of MEK1/2 inhibition on the tumor microenvironment (TME) of MAPK-driven HNC, elucidate tumor-host interaction mechanisms facilitating immune escape on treatment, and apply rationale-based therapy combination immunotherapy and MEK1/2 inhibitor to induce tumor clearance.

Methods

Mouse syngeneic tumors and xenografts experiments were used to analyze tumor growth in vivo. Single-cell cytometry by time of flight, flow cytometry, and tissue stainings were used to profile the TME in response to trametinib (MEK1/2 inhibitor). Co-culture of myeloid-derived suppressor cells (MDSC) with CD8⁺ T cells was used to measure immune suppression. Overexpression of colony-stimulating factor-1 (CSF-1) in tumor cells was used to show the effect of tumor-derived CSF-1 on sensitivity to trametinib and anti-programmed death- 1 (αPD-1) in mice. In HNC patients, the ratio between CSF-1 and CD8A was measured to test the association with clinical benefit to αPD-1 and αPD-L1 treatment.

Results

Using preclinical HNC models, we demonstrated that treatment with trametinib delays HNC initiation and progression by reducing tumor cell proliferation and enhancing the antitumor immunity of CD8⁺ T cells. Activation of CD8⁺ T cells by supplementation with αPD-1 antibody eliminated tumors and induced an immune memory in the cured mice. Mechanistically, an early response to trametinib treatment sensitized tumors to αPD-1-supplementation by attenuating the expression of tumor-derived CSF-1, which reduced the abundance of two CSF-1R⁺CD11c⁺ MDSC populations in the TME. In contrast, prolonged treatment with trametinib abolished the antitumor activity of αPD-1, because tumor cells undergoing the epithelial to mesenchymal transition in response to trametinib restored CSF-1 expression and recreated an immune-suppressive TME.

Conclusion

Our findings provide the rationale for testing the trametinib/αPD-1 combination in HNC and highlight the importance of sensitizing tumors to αPD-1 by using MEK1/2 to interfere with the tumor–host interaction. Moreover, we describe the concept that treatment of cancer with a targeted therapy transiently induces an immune-active microenvironment, and supplementation of immunotherapy during this time further activates the antitumor machinery to cause tumor elimination.

Diffusion Reflection Method for Early Detection of Oral Squamous Cell Carcinoma Specifically Targeted by Circulating Gold-Nanorods Bio-Conjugated to Anti-Epidermal Growth Factor Receptor

BACKGROUND

Translation of nanomedical developments into clinical application is receiving an increasing interest. However, its use for oral squamous cell carcinoma (OSCC) diagnosis remains limited. We present an advanced nanophotonic method for oral cancer detection, based on diffusion reflection (DR) measurements of gold-nanorods bio-conjugated to anti-epidermal growth factor receptor (C-GNRs) specifically attached to OSCC cells.

OBJECTIVE

To investigate in a rat model of oral carcinogenesis the targeting potential of C-GNRs to OSCC by using the DR optical method.

MATERIALS AND METHODS

OSCC was induced by the carcinogen 4-nitroquinoline-N-oxide (4NQO). C-GNRs were introduced locally and systemically and DR measurements were recorded from the surface of the rat tongue following illumination with red laser beam. Rats were divided into experimental and control groups. The results were compared with the histologic diagnosis.

RESULTS

A total of 75 Wistar-derived rats were enrolled in the study. Local application did not reveal any statistical results. DR measurements following intravenous injection of C-GNRs revealed a significant increase in light absorption in rats with OSCC compare with rats without cancer (p<0.02, sensitivity 100%, specificity 89%). In addition, absorption of light increased significantly in cases of severe dysplasia and cancer (high risk) compared to rats without cancer and rats with mild dysplasia (low risk) (86% sensitivity and 89% specificity, AUC=0.79).

CONCLUSION

Combining nanotechnology and nanophotonics for in vivo diagnosis of OSCC serves as additional tier in the translation of advanced nanomedical developments into clinical applications. The presented method shows a promising potential of nanophotonics for oral cancer identification, and provides support for the use of C-GNRs as a selective drug delivery.

In Vitro Establishment of a Genetically Engineered Murine Head and Neck Cancer Cell Line using an Adeno-Associated Virus-Cas9 System

The use of primary normal epithelial cells makes it possible to reproducibly induce genomic alterations required for cellular transformation by introducing specific mutations in oncogenes and tumor suppressor genes, using clustered regulatory interspaced short palindromic repeat (CRISPR)-based genome editing technology in mice. This technology allows us to accurately mimic the genetic changes that occur in human cancers using mice. By genetically transforming murine primary cells, we can better study cancer development, progression, treatment, and diagnosis. In this study, we used Cre-inducible Cas9 mouse tongue epithelial cells to enable genome editing using adeno-associated virus (AAV) in vitro. Specifically, by altering KRAS, p53, and APC in normal tongue epithelial cells, we generated a murine head and neck cancer (HNC) cell line in vitro,which is tumorigenic in syngeneic mice. The method presented here describes in detail how to generate HNC cell lines with specific genomic alterations and explains their suitability for predicting tumor progression in syngeneic mice. We envision that this promising method will be informative and useful to study tumor biology and therapy of HNC.

Non- Hodgkin lymphoma of the lips: A rare entity

AIM

To investigate clinico-pathological features of lymphoma of the lips, and review the literature.

MATERIALS AND METHODS

Retrospective analysis and review of English literature, 1996-2016.

RESULTS

Analysis included 23 cases, 7 new cases and 16 from literature, 12 M: 11 F, age 7-82 years. Four occurred in children, mean age 10.1; 19 in adults, mean 61.1 years. The lower lip was involved in the majority of cases (16, 69.56%). 14 (60.87%) were isolated to the lips, 8 (34.78%) were multifocal. Nine (39.13%) occurred in association with Sjogren's syndrome, of which one also had Hashimoto thyroiditis. IgG4-related disease and HIV were reported in one case each. The lip salivary glands were involved in most cases (19, 82.6%); 3 (13.6%) showed only cutaneous involvement. The typical presentation was single or multiple nodules (15, 65.21%), with surface ulceration in only two (8.69%). Constituent symptoms were absent in all cases, paresthesia was reported in one (4.34%). The majority (18, 78.26%) was extranodal marginal zone B-cell lymphoma - mucosa-associated lymphoid tissue lymphoma (EMZB-MALT), and one case each was mantle cell, NK-T cell, CD30 positive and plasmablastic lymphoma.

CONCLUSION

The lips seem to have a unique pattern of non-Hodgkin lymphoma dominated by EMZB-MALT lymphoma, rarely other types. In more than half, neither Sjogren's syndrome nor other chronic inflammation was identified. Lesions tend to present as asymptomatic slowly progressing, non-ulcerated submucosal masses. Lymphoma should be considered even in the absence of constituent symptoms, as most cases showed none. Although the number of reported cases is rather small, disease course is usually prolonged and prognosis seems to be good.

Oral variant of acantholytic squamous cell carcinoma-Histochemical and immunohistochemical features

Acantholytic squamous cell carcinoma (ASCC) is an uncommon variant of squamous cell carcinoma (SCC). It is characterized by a combination of typical SCC and pseudoglandular structures, dyskeratotic cells and prominent acantholysis. The purpose of this study was to analyze the histochemical and immunohistochemical characteristics of the intraoral variant of ASCC. Cases of intraoral ASCC were retrieved from the English language literature. Four new cases from our files were added. In total, 35 cases were included and analyzed in this study. The mean age of the patients was 61.5 + 13 years (age range 38-92 years), with a male-to-female ratio of 1.7:1. According to the available data, histochemical and immunohistochemical stains for mucins were found to be consistently negative. E- cadherin, a marker of adherens junctions, was usually reported to be expressed in areas of "typical" (non acantholytic) SCC, but reduced in the acantholytic areas. We examined for the first time the expression of claudin 1, a marker of tight junctions, and found it to be reduced in the acantholytic areas, similar to E-cadherin. Several cases of oral ASCC also expressed vimentin and cytokeratin (CK) 19, markers associated with epithelial-mesenchymal transition. A wide range of non-epithelial markers yielded negative immunoreactions. In conclusion, ASCC is an uncommon variant of squamous cell carcinoma. The acantholytic process appears to involve reduced expression of molecular components of both adherens junctions and tight junctions. These findings could suggest a relation to the epithelial mesenchymal transition process and therefore further studies are needed in order to establish such a link and the subsequent possible impact on the clinical outcome of the patients.

Building the European Nanomedicine Research and Innovation Area: 10 years funding innovative research projects

EuroNanoMed (ENM) is an ERA-NET for nanomedicine. ERA.NET is an EU funded network which had been established to support and increase the coordination of European research programmes and related funding. It is a platform for funding agencies and ministries to develop joint activities and programmes with the aim of coordinating high-quality research in diverse research fields, in this case nanomedicine, across national borders. It has been 10 years since the establishment of EuroNanoMed presently in its third phase. For those 10 years, Research and Innovation funding organizations in Europe and beyond have been joining forces to fund excellent innovative research projects in the main 3 topics defined by the European Technology Platform on Nanomedicine: targeted drug delivery, diagnostics and regenerative medicine. Ten joint transnational calls have been launched (the 10th call is ongoing). So far, 90 transnational projects have been funded, including 460 research groups from over 20 countries. In the Joint Transnational Call 2017—co-funded by national and regional funding organizations and the European Commission—16 projects were funded with a total investment of 14 million euros, including 3.3 million euros from the European Commission. In addition to EuroNanoMed's main activity of funding transnational innovative research projects, it collaborates with sister initiatives in nanomedicine and translational research. ENM has organised review seminars as well as safety, ethics and regulatory affairs training workshops. The purpose of this article is to summarise the activities of EuroNanoMed over the last 10 years.

Tongue Lumps and Bumps: Histopathological Dilemmas and Clues for Diagnosis

Exophytic lesions of the tongue encompass a diverse spectrum of entities. These are most commonly reactive, arising in response to local trauma but can also be neoplastic of epithelial, mesenchymal or miscellaneous origin. In most cases, the microscopic examination is likely to provide a straightforward diagnosis. However, some cases can still raise microscopic diagnostic dilemmas, such as conditions that mimic malignancies, benign tumors with overlapping features and anecdotal lesions. A series of "lumps and bumps" of the tongue are presented together with suggested clues that can assist in reaching a correct diagnosis, emphasizing the importance of the clinico-pathological correlations.

Ethical issues in nanomedicine: Tempest in a teapot?

Nanomedicine offers remarkable options for new therapeutic avenues. As methods in nanomedicine advance, ethical questions conjunctly arise. Nanomedicine is an exceptional niche in several aspects as it reflects risks and uncertainties not encountered in other areas of medical research or practice. Nanomedicine partially overlaps, partially interlocks and partially exceeds other medical disciplines. Some interpreters agree that advances in nanotechnology may pose varied ethical challenges, whilst others argue that these challenges are not new and that nanotechnology basically echoes recurrent bioethical dilemmas. The purpose of this article is to discuss some of the ethical issues related to nanomedicine and to reflect on the question whether nanomedicine generates ethical challenges of new and unique nature. Such a determination should have implications on regulatory processes and professional conducts and protocols in the future.

Gold nanorods reflectance discriminate benign from malignant oral lesions

Nanoparticle-based contrast agents have been used as an imaging tool for selectively detecting cancerous processes. We aimed to evaluate the detection sensitivity of reflection measurements of gold nanorods (GNRs) bio-conjugated to anti-epidermal growth factor receptor (GNRs-EGFR) monoclonal antibodies in discriminating benign from premalignant and malignant human oral lesions. Tissue sections incubated with GNRs-EGFR and the reflectance spectrum was measured using hyperspectral microscopy. Reflectance intensity increased with the progression of the disease, lowest in the control group and increasing as the dysplastic changes increase (P<0.001 for linear trend of grade). Intensity was significantly higher in the moderate and severe dysplasias and cancer patients than in the controls and mild dysplasia (t test P=0.0003, Mann-Whitney P<0.0001). The GNRs reflection measurements can discriminate benign and mild dysplastic lesions from the more severe dysplasia and invasive cancer, suggesting an objective, not dependent on the qualification of a technician and with less interpretation errors.

Scrolls: novel microparticulate systems for enhanced delivery to/across the skin

We describe the scroll system as a new microparticulate structured delivery system for enhanced delivery to/across the skin. The basic components of the scroll system are non-ionic surface active of the type of alkyl polyglycol ethers and a glycol. The unique structures are preserved with addition of various ingredients such as polymers, vegetable oils, pharmaceuticals, and permeation enhancers but are dismissed when amphiphile is withdrawn. The microparticles have a unique scroll structure with multiple "wrapping." Besides enabling superior permeation of drugs into/across the skin, the drugs delivered by scroll systems were more effective in vitro and in vivo compared to controls. Model drugs presented high entrapment capacity in scroll systems. The systems are stable over time and are safe for skin application. In order to form, they require a small number of ingredients, simple preparation method, and are environment friendly. The scroll systems may be new potential tools in the dermal/transdermal pharmaceutical and cosmetic industry.

Programmed cell removal biomarkers calreticulin and CD47 implicated in oral lichen planus

OBJECTIVES

To investigate the expression of the programmed cell removal markers, calreticulin (CRT) and CD47, known to be involved in various autoimmune diseases, in patients with oral lichen planus (OLP), and to investigate the association with clinical behavior.

MATERIALS AND METHODS

Biopsies of 78 patients with OLP were included. The clinical data were collected from patients' charts. The expression of CRT and CD47 was immunomorphometrically analyzed in the epithelial (CRTep, CD47ep) and inflammatory cells (CRTinf, CD47inf), and the results were correlated with the clinical presentation.

RESULTS

The epithelial and inflammatory cells expressed CRT (2.83 ± 6.62 and 5.13 ± 3.72) and CD47 (7.92 ± 4.6 and 10.7 ± 7.16). The expressions of CD47ep and CD47inf were associated (R = 0.64, P < 0.0005) with one another. The expressions of CRTinf and CD47ep were higher in atrophic erosive forms (A/ELP) than in the keratotic form of patients with OLP (6.46 ± 0.76 and 9.38 ± 0.87 vs 4.2 ± 0.61 and 6.84 ± 0.91, respectively, P = 0.002 and P = 0.021). The expression of CRTep was associated with more localized lesions (P < 0.009) and more abundant in males (P = 0.049), and the expression of CRTinf was associated with the presence of skin lesions and symptoms (P < 0.034 and P = 0.047, respectively). Only in A/ELP patients, the expression of CRTep was associated with high expression of CD47ep (R = 0.6, P = 0.004), where both CD47ep and CD47inf were associated with lower age of the patients (R = -0.48, P = 0.03 and R = -0.54, P = 0.01).

CONCLUSIONS

The pattern of expression of CRT and CD47 in OLP suggests a general programmed cell removal response in OLP. Symptomatic patients may benefit from CRT/CD47 targeted therapy in the future.

Metastatic tumors to the jaws and mouth

Metastatic dissemination to the oral cavity is rare and is usually the evidence of a wide spread disease with an average survival rate of 7 months. In almost a quarter of the cases, oral metastasis was found to be the first indication of an occult malignancy at a distant site. Metastatic lesions can be found anywhere in the oral cavity, however, the jaw bones with the molar area is the most frequently involved site. In the oral soft tissues, the gingiva is the most common site, suggesting the possible role of inflammation in the attraction of metastatic deposits. The most common primary malignancies presenting oral metastases were the lung, kidney, liver, and prostate for men, and breast, female genital organs, kidney, and colo-rectum for women. Most patients with jawbone metastasis complain of swelling, pain, and paresthesia. An exophytic lesion is the most common clinical presentation of metastatic lesions in the oral soft tissues. Early lesions, mainly those located in the gingiva, may resemble a hyperplastic or reactive lesion. Once a lesion is recognized as metastasis, the primary tumor site should be identified following clinical, radiological and histopathological investigations. If standardized diagnostic workup fails to detect the site of origin, then the term carcinoma of unknown primary is applied. Personalized medicine tools such as tissue-of-origin assays should be applied, either by immunohistochemical testing or by molecular-profiling methods as these may lead to a more favorable outcome.

The clinical characteristics of benign oral mucosal tumors

Objectives: To investigate the clinical characteristics and pre-biopsy provisional diagnoses of benign oral mucosal tumors. Material and Methods: A 10- year retrospective analysis of all benign tumors of the oral mucosa, from a university- affiliated oral and maxillofacial surgery department. Results: 146 benign tumors were included. The mean age was 49.6 years, with an approximately equal gender distribution. The most prevalent tumor types were lipomatous tumors (27.4%), vascular (23.3%), and salivary gland tumors (16.5%). Tongue, labial and buccal mucosa were the most frequently involved sites. The vast majority (98.6%) presented as non-ulcerated masses. Only 2 (1.4%) presented as ulcerated masses. The clinical provisional diagnosis correctly classified lesions as non-malignant in 93.3%. In only 9 (6.7%) suspicion of malignancy was included in the provisional diagnosis. However, benign neoplasia was unsuspected in 42.1% of tumors. These cases were clinically classified as reactive. Conclusions: Benign tumors were most likely to be clinically correctly classified as non-malignant, but even in the setting of experienced oral surgeons, neoplasia was unsuspected in more than 40% of cases. This data strongly supports the need to biopsy every oral mucosal mass, since inaccurate clinical evaluation of the lesion’s biological nature was a frequent event.

Key words:Malignant, benign, reactive, ulcerated mass, non-ulcerated mass, clinical diagnosis.

Topical simvastatin improves the pro-angiogenic and pro-osteogenic properties of bioglass putty in the rat calvaria critical-size model

Objective was to describe the effect of bioactive glass putty with and without topical simvastatin on new bone formation in critical-sized defects of rat calvaria. A calvarial bone defect was created in 20 male Wistar rats and filled with bioactive glass alone (n = 10) or combined with simvastatin (n = 10). After 4 weeks, the defects were histomorphometrically evaluated for volume fraction (Vv) of woven bone, vessel density, bioglass quantity, and inflammation. Compared to the bioglass-only group, rats treated with simvastatin had greater Vv of blood vessels (3.3% ± 0.7 vs 1.6% ± 0.1, P = .0002) and new bone (2.3% ± 0.2 vs 1.8% ± 2.5, P = .003). The Vv of the bioglass remnants in the bioglass-only group was higher than in the group treated with simvastatin (2.4% ± 0.08 vs 1.7% ± 0.3, P < .0004). Chronic inflammation was noted in 1 rat from each group. Topical simvastatin seems to improve the pro-angiogenic and pro-osteogenic properties of bioglass putty in rat calvaria critical-size defects without significant inflammation.

Metallothionein, a marker of antiapoptosis, is associated with clinical forms of oral lichen planus

OBJECTIVES

To investigate the expression of anti- and proapoptosis markers, metallothionein (MT), and caspase-2, in the epithelial and inflammatory cells of oral lichen planus (OLP) patients, and to investigate the association with clinical parameters.

MATERIALS AND METHODS

Included were biopsies of 70 OLP patients. The clinical data were collected from patients' charts. The expression of MT and caspase-2 was immunomorphometrically analyzed in the epithelial and inflammatory cells, and the results were correlated with the clinical presentation.

RESULTS

The epithelial and inflammatory cells expressed MT (10.2 ± 5.75 and 0.68 ± 0.86) and caspase-2 (1.54 ± 2.6 and 0.98 ± 1.15) which show a trend toward an inverse expression. The expression of MT in the epithelium was significantly higher in patients presenting with keratotic lichen planus than in patients with the atrophic and erosive forms (P = 0.0008). In the inflammatory cells, the expression of MT was inversely correlated with increasing age (R = 0.34, P = 0.0069).

CONCLUSIONS

The pattern of expression of MT and caspase-2 in OLP suggests an extensive antiapoptotic response in the keratotic form of the disease. Symptomatic patients may benefit from therapy targeted to apoptosis in the future.

HIF-1α, VEGF, and EGFR: contributing factors in the pathogenesis of necrotizing sialometaplasia

OBJECTIVES

Necrotizing sialometaplasia (NS) is an uncommon reactive lesion involving the minor salivary glands. This study aimed to investigate the expression of hypoxia-inducible factor alpha (HIF-1α), vascular endothelial growth factor (VEGF), and epithelial growth factor receptor (EGFR) in the pathogenesis of NS.

METHODS

Paraffin-embedded tissue sections from 10 cases of NS were immunohistochemically stained for HIF-1α, VEGF, and EGFR. A semiquantitative morphometric analysis was performed and compared with normal palatal salivary glands and traumatic ulcerations.

RESULTS

Hypoxia-inducible factor alpha staining was observed in most elements of the affected area, the acini and ducts of the involved salivary glands as well as in the inflammatory infiltrate, the endothelial cells, and stromal cells. HIF-1α was almost absent in the control glands (P < 0.0001). VEGF staining was positive in the stromal capillaries and in the inflammatory infiltrate. The expression was higher in cases of NS compared with the normal salivary glands (P < 0.001). EGFR was expressed in the surface epithelium, the pseudo-epitheliomatous hyperplasia, and the islands of squamous metaplasia. VEGF expression in traumatic ulcerations was lower than that in cases of NS.

CONCLUSION

This study provides molecular evidence to the role of hypoxia in NS; HIF-1α, the main regulator of hypoxia, was expressed in the infarcted salivary glands, EGFR in the metaplastic epithelium and VEGF in the stromal capillaries, all three components are the key factors induced by hypoxia.

Re-evaluation of common paradigms regarding the clinical appearance of oral mucosal malignancies

PURPOSE

To evaluate the clinical appearance and rate of ulceration of oral mucosal malignancies, and to investigate the accuracy of clinical provisional diagnoses.

METHODS

A 10-year retrospective analysis, which included diagnostic biopsies of malignant tumors of the oral mucosa. The clinical provisional diagnoses were compared with final diagnoses.

RESULTS

Two hundred and twenty-seven oral mucosal malignant tumors were included. Squamous cell carcinoma and its variants accounted for the majority (78%) of all malignant tumors. The most common clinical presentations were non-ulcerated (59.7%) and ulcerated masses (20.4%). Only 11.9% presented as indurate ulcers. The highest ulceration rate of all malignancies was recorded for SCC, with only about half of SCC and its variants ulcerated at the time of biopsy. 31.1% of all malignancies were not clinically suspected to be malignant and did not even include a request to rule out malignancy. There was a better agreement between the clinical provisional diagnoses and microscopic diagnoses in the SCC group than in other types of malignancy (P < 0.001).

CONCLUSION

Within this study sample, non-ulcerated masses rather than indurate ulcers are the most common clinical appearance of oral mucosal malignancies, and even for SCC, that showed the highest ulceration rate at presentation, half were non-ulcerated. Approximately, one-third of oral mucosal malignancies were not suspected to be malignant prior to biopsy. Thus, the level of suspicion currently reserved for mucosal ulcers and ulcerated masses should also be applied to non-ulcerated oral mucosal masses.

Metastatic tumors to the gingiva and the presence of teeth as a contributing factor: a literature analysis

BACKGROUND

Gingiva that is prone to inflammation may serve as a pre-metastatic niche for the attraction of circulating malignant cells. The aim of this study is to analyze cases of metastatic lesions to the gingiva compared with cases metastasizing to other oral mucosal sites. The pathogenesis of gingival metastases is discussed, with emphasis on the role of inflammation.

METHODS

The English-language literature between 1916 and 2011 was searched for cases of metastatic lesions to the oral mucosa; only cases metastasizing in the oral mucosa, gingiva, and periodontium were included.

RESULTS

Two hundred seven cases were included. The gingiva was the most common site (60.4%), followed by tongue and tonsil. The most common primary sites were lung (24.2%), kidney (13.5%), skin (10.6%), and breast (8.7%). In 27%, the oral lesion was the first sign of a malignant disease. In most cases, the lesion appeared as an exophytic mass (96%) diagnosed clinically as a reactive gingival lesion. The presence of teeth was significantly associated with the development of gingival metastases: in 108 of 125 gingival metastases, the lesion was found adjacent to teeth (P <0.001; odds ratio = 8.2). The average life expectancy after diagnosis of the metastasis was 3.7 months.

CONCLUSIONS

The gingiva is the most common site for metastases to oral soft tissues, with strong association with the presence of teeth. This finding may be related to the role of inflammation in the attraction of metastatic cells to chronically inflamed gingiva.

Expression of the homeostasis-related markers, maspin, heat shock proteins 70 & 90, glutathione S-transferase, aquaporin 5 and NF-kB in young and old labial and palatal salivary glands

Intraoral salivary glands undergo remarkable age-related morphologic changes. This study investigated the expression of a panel of molecular markers known for cellular homeostatic activity, dependent on age and location of the salivary glands. Samples taken from healthy subjects were classified according to age ("young" <45 years, n=51, and "old" ≥60 years, n=45) and location (lip, n=47 and palate, n=49). They were immunohistochemically stained for mammary serine protease inhibitor (maspin), heat shock protein (HSP)70, HSP90, glutathione S-transferase (GST), aquaporine5 (AQP5), and nuclear factor kappa-B (NF-κB) for assessment of their expression in acini and ducts, and in cytoplasmic and nuclear compartments. Results were expressed as the mean percentage of positively stained component per age group, gland location and type of cell and cellular compartment. Statistical analysis was performed by two-way ANOVA and crosstabs. The expression of maspin was lower in the old group in both the palatal and labial glands (acini and ducts, cytoplasm and nuclei) compared to the young group (p<0.05). In both age groups, when compared to labial glands, palatal glands exhibited higher expression of HSP70 (p<0.05) and lower expression of AQP5 (p<0.001) and NF-κB (p=0.018). Collectively, the low expression of factors capable of preserving cellular homeostasis (i.e., maspin and AQP5) vis-à-vis a high expression of factors that are also related to cell survival (i.e., HSPs) that was demonstrated in the old palatal glands may point to their high vulnerability to undergo selective phenotypic changes.

The significance of surface ulceration as a sign of malignancy in exophytic oral mucosal lesions: myth or fact?

To compare the spectrum of pathologies in ulcerated versus non-ulcerated exophytic oral mucosal lesions and explore the significance of surface ulceration as an indication of malignancy. Retrospective analysis of exophytic lesions of the oral mucosa, 2009-2011. 713 biopsies of exophytic lesions of oral mucosa were included, of which 9.4% were ulcerated. Significant differences were found between ulcerated and non-ulcerated lesions. Of the ulcerated lesions 67.2% were reactive, 31.3% malignant and 1.5% benign, compared to 86, 8.4 and 5.6% respectively in non-ulcerated lesions (p < 0.0001). Malignancies were most prevalent in ulcerated lesions, in patients over 50. Malignancies presented the highest ulceration rate (36.8%, p < 0.001), compared to reactive (7.5%) and benign neoplasia (1.8%), however, the majority of oral mucosal malignancies (63.2%) presented as non-ulcerated masses. Squamous cell carcinoma presented the highest ulceration rate among malignancies, but even these were only ulcerated in 50% of cases. Non-epithelial malignancies were non-ulcerated in all cases. One-third of all malignancies were not suspected as such clinically, however, there was a better agreement between the clinical and microscopic diagnosis of malignancy in ulcerated lesions. Although the statistical likelihood of ulcerated masses to represent malignancy was higher than non-ulcerated lesions, especially in patients over 50, the majority of malignancies presented as non-ulcerated masses. Thus, all exophytic lesions should be submitted for microscopic analysis, and the status of ulceration should not be regarded neither as a factor in the decision to biopsy, nor a reliable indicator for malignancy.

E-cadherin in oral SCC: an analysis of the confusing literature and new insights related to its immunohistochemical expression

E-cadherin plays a crucial structural role in cell-cell contacts in epithelial tissues, and a functional role in signaling pathways that regulate cell proliferation, differentiation, and survival. Reduced immunoexpression of E-cadherin adhesions is largely considered as being equivalent to defective functionality and malignancy, and has been used as a prognostic parameter. A critical analysis of studies on E-cadherin immunoexpression in oral carcinomas revealed a wide range of both technical and interpretational aspects. This paper highlights biological characteristics of E-cadherin with respect to its expression in normal and neoplastic epithelial cells and to its interrelations with the tumor microenvironment that can have an impact on immunohistochemical results and their application in the clinical setting.

Lipomatous tumors of the oral mucosa: histomorphological, histochemical and immunohistochemical features

We conducted a comprehensive study of all lipomatous tumors of the oral mucosa (1996-2008) accessioned at the Department of Oral Pathology, Tel Aviv University, collected demographic data and analyzed multiple histomorphological features. Furthermore, we examined the immunostaining of aP2 (adipocyte lipid binding protein) and the polarization colors of picrosirius red (PSR)-stained collagen fibers in order to test their potential in differentiating between benign and malignant tumors. All cases were immunohistochemically stained with aP2 antibody; only tumors with considerable collagenous stroma were selected for the PSR staining. A total of 77 tumors were included in the study, 91% benign and 9% malignant. Fibrolipoma (37.7%) and lipoma (36.4%) were the most frequent tumors. Atypical lipomatous tumor (ALT) was the only type of malignancy. The most common location for the benign tumors was the buccal mucosa and for ALT, the tongue. Histomorphological features characteristic of malignant tumors were occasionally present also in the benign entities. Expression of aP2 was similar in all tumors, while the polarization colors of the PSR-stained collagen fibers differed significantly between ALT and benign tumors (p<0.05). Benign and malignant tumors occasionally show overlapping histomorphological features that require a meticulous examination. PSR staining with polarization microscopy could aid in differentiating malignant from benign tumors in equivocal cases.

The effect of desalivation on the malignant transformation of the tongue epithelium and associated stromal myofibroblasts in a rat 4-nitroquinoline 1-oxide-induced carcinogenesis model

The aim of our study was to analyse desalivated rat tongue epithelium for histopathological changes, proliferating cell nuclear antigen (PCNA), and epithelium-associated stromal myofibroblasts [SMF; alpha-smooth muscle actin (alphaSMA)] following 0.001% 4-nitroquinoline 1-oxide (4NQO) administration in drinking water. Results were compared with those of identically treated but salivated specimens. 4NQO was administered for 7, 14, 22 and 28 weeks. Tongue length was divided into anterior, middle and posterior 'thirds'. The histopathological changes per 'third' were scored as normal epithelium, hyperplasia, dysplasia, carcinoma-in-situ, and superficial and invasive carcinoma. The PCNA and alphaSMA stains were assessed by a point-counting method. At all time points, the histopathological changes in the anterior and middle thirds were higher in the desalivated than in the salivated group (P < 0.05) but almost identical in the posterior third (P > 0.05). PCNA scores were significantly lower in the desalivated vs. the salivated group at almost all time points and tongue thirds (P < 0.05). SMF were usually scarce in both groups, but there was a significant surge in the posterior third at 28 weeks: the score in the desalivated group was only about one-half that of the salivated group (P < 0.05). The absence of saliva seems to promote malignant transformation of the tongue epithelium in the early stages. PCNA cannot be regarded as a marker of proliferation and probably contributes to this process by other mechanisms. Emergence of SMF seems to be highly dependent on growth factors from saliva in addition to factors from cancerous cells.

Is maspin immunolocalization a tool to differentiate central low-grade mucoepidermoid carcinoma from glandular odontogenic cyst?

Mucoepidermoid carcinoma (MEC) of the salivary glands has a low-grade variant (LGMEC), which may be found within the jawbones. LGMEC shares a number of histopathological similarities with glandular odontogenic cysts (GOC) of the jawbones. Maspin has been identified in several benign and malignant salivary gland neoplasms. We investigated the immunolocalization of maspin in LGMEC and GOC and evaluated its potential to distinguish between these two entities. Cases of LGMEC (n=6), GOC (n=8) and various odontogenic cysts with marked mucous metaplasia (OCMM, n=7), which served as controls, were immunohistochemically labeled for the binding of an antibody directed against maspin. Immunomorphometry was performed separately for maspin-immunopositive epithelial cells and epithelial-mucous cells in either their nuclear or cytoplasmic compartments. Results were presented as the volume fraction (Vv) of each element. The Vv of the maspin-immunopositive epithelial-mucous cytoplasm and nuclei was significantly higher in LGMEC than in GOC and OCMM (p<0.001 and p=0.026, respectively). In the epithelial cells, no significant differences were observed among the lesions (p>0.05). It is suggested that the high levels of maspin in the epithelial-mucous cells (in both cytoplasm and nuclei) in LGMEC may serve as a tool to distinguish it from GOC. This may be useful especially in equivocal cases and in small incisional biopsy samples.

Stromal myofibroblasts accompany modifications in the epithelial phenotype of tongue dysplastic and malignant lesions

Stromal myofibroblasts (SMF) associated with various types of carcinomas are believed to emerge under the influence of the tumor cells. Recent studies have shown that SMF may originate from fibroblasts within the tumor stroma or even from carcinoma cells by the process of epithelial-mesenchymal transition. The aim of this study was to investigate the concomitant expression of epithelial membrane antigen and α-smooth muscle actin in cells at the tumor-connective tissue interface in human tongue carcinoma, as a possible reflection of epithelial-mesenchymal transition. Given its key role in this process, expression of transforming growth factor-β in the malignant cells was assessed as well. Immunostaining with α-smooth muscle actin was performed on cases of hyperplasia (n = 16), mild dysplasia (n = 12), moderate-to-severe dysplasia (n = 11) and carcinoma (n = 22). Transforming growth factor-β assessment and double immunostaining with epithelial membrane antigen and α-smooth muscle actin were performed only in cases of carcinoma. SMF were significantly associated with carcinomas, while their number in pre-malignant lesions (hyperplasia and dysplasia) was significantly lower (P < 0.001). Although SMF were found in all carcinomas, they were heterogeneous in their frequency and patterns of distribution. In addition, 95% of the carcinomas expressed transforming growth factor-β and 41% exhibited cells positive for both epithelial membrane antigen and α-smooth muscle actin. SMF were almost exclusively associated with established carcinomas and not with pre-malignant lesions. Cells that co-expressed epithelial membrane antigen and α-smooth muscle actin can be a manifestation of epithelial-mesenchymal transition and, as such, may serve as a source for SMF in these tumors. These findings appear to be linked to the frequent expression of transforming growth factor-β by the malignant cells.

Stromal myofibroblasts and malignant transformation in a 4NQO rat tongue carcinogenesis model

This study assesses the correlation of changes in the density of stromal myofibroblasts to propagation of histopathologic alterations and proliferative activity of the epithelium in a rat 4NQO-induced tongue rat carcinogenesis model.Forty-three male Wistar rats were administered 0.001% 4NQO in drinking water for: 0 (n=7, control), 7 (n=4), 8 (n=8), 14 (n=6), 22 (n=9), and 28 (n=9) weeks, after which they were euthanized. Tongue sections were divided equally into anterior, middle and posterior thirds. Each third was given a histopathologic score (hematoxylin and eosin), ranging from normal, hyperplasia/hyperkeratosis, and escalating degrees of dysplasia to carcinoma, and analyzed by the point-counting method for density of epithelium-associated stromal myofibroblasts (alphaSMA) and of proliferating epithelial cells (PCNA). Histopathologic changes significantly increased in severity (carcinoma) with duration of 4NQO administration (p<0.001) in the posterior third of the tongue. The density of stromal myofibroblasts and proliferating epithelial cells was significantly higher in the posterior third of the tongue at 28 weeks compared to the other time points and locations (p<0.001, p=0.01, respectively). Significant correlations were found between occurrence of carcinoma and the increase in density of stromal myofibroblasts (p<0.001) and of proliferating epithelial cells (p=0.001) in the posterior third of the tongue. Increased density of stromal myofibroblasts was distinctively associated with the development of carcinoma but not with pre-malignant changes. Defining the mechanism of evolvement of carcinoma-associated stromal myofibroblasts is expected to further broaden our knowledge on the micro-environmental events occurring during the malignant transformation.

Clinico-pathologic correlations of myofibroblastic tumors of the oral cavity. II. Myofibroma and myofibromatosis of the oral soft tissues

BACKGROUND

Myofibroma is a solitary benign tumor of myofibroblasts. Myofibromatosis describes multiple, simultaneous myofibromas at different sites in various organs. The clinico-pathologic correlations of myofibroma/myofibromatosis confined only to oral soft tissues were analyzed.

METHODS

In the English language literature, 41 myofibroma and 12 myofibromatosis cases involving the oral soft tissues were found. From our files, three new myofibroma cases were added.

RESULTS

Age at time of diagnosis of oral mucosa myofibroma ranged from birth to 70 years (mean 21.7 years), considerably higher than myofibroma in other parts of the body. Lesions occurred during the first decade (44%) and in the first year of life (17%). Male:female ratio was 1:1.6, contrary to the male predominance in other parts of the body. Common sites were the tongue (32%) and buccal mucosa (18%). Treatment was local excision, either complete (n = 13) or partial (n = 3), wide excision (n = 4), surgery, and chemotherapy (n = 1). Myofibromatosis involving oral soft tissues was diagnosed at birth in nine (75%) patients, within the first year in two, and as a young adult in one. Male:female ratio was 2:1. The tongue was the most common site (50%). Half the patients died of disseminated disease within a few days from birth, three were cured by partial or complete excision, and three experienced spontaneous regression. Histologically, oral mucosa myofibroma/myofibromatosis appearance agreed with findings in the literature.

CONCLUSIONS

Myofibroma should be included in the clinical differential diagnosis of masses of the oral soft tissues, especially in the tongue and buccal mucosa of children and adolescents. Histological differential diagnosis includes benign and malignant spindle-shaped lesions. Treatment of choice is local excision.

Central (intraosseous) myofibroma of the mandible: clinical, radiologic, and histopathologic features of a rare lesion

OBJECTIVE

Myofibroma frequently manifests as a solitary soft tissue tumor and less as simultaneous multiple tumors in both soft tissues and bones. The present study evaluated clinical, radiological, and histopathologic features of myofibroma of the jaws.

STUDY DESIGN

Nineteen cases from the literature and 4 new cases were analyzed.

RESULTS

At initial diagnosis, age ranged from birth to 34 years (mean 7.2 years, median 6 years). Male/female ratio was 2.3:1. Myofibromas were radiolucent solitary lesions located solely in the mandible: 70% unilocular, 30% multilocular; 67% with well-defined borders. Conservative treatment was performed on 75% of the patients; 25% underwent partial jaw resection. Where information was provided, no lesion recurred during 6-month to 17-year follow-up.

CONCLUSION

Although rare, myofibroma of the mandible should be considered in the differential diagnosis of radiolucent lesions (particularly unilocular), especially in children. Treatment of choice is conservative surgery to minimize potential functional and/or esthetic damage.

Stromal differences in salivary gland tumors of a common histopathogenesis but with different biological behavior: a study with picrosirius red and polarizing microscopy

Salivary gland neoplasms - pleomorphic adenoma, polymorphous low-grade adenocarcinoma, and adenoid cystic carcinoma - share a common histogenetic trait, but differ markedly in their biological properties. The objective of the study was to assess the polarization colors of picrosirius red-stained stromal collagen fibers in these salivary gland neoplasms to evaluate their possible role in the histopathogenesis of the tumors and to evaluate the potential usefulness of this approach as a diagnostic tool. Ten cases of each tumor type and 10 cases of mucous extravasation phenomenon (control) were examined using picrosirius red staining and polarizing microscopy. In each case, at least 50 thin ( approximately 0.8 microm) and 50 thick (1.6-2.4 microm) collagen fibers were counted and classified as green-yellow or yellow-orange, the mean percentage was calculated and statistical differences analyzed by one-way ANOVA. Results showed a similar thin fiber distribution in all tumor types and controls (82-88% green-yellow, 12-18% yellow-orange, p>0.05). Thick fibers showed a different distribution in polymorphous low-grade adenocarcinoma and adenoid cystic carcinoma (approximately 50% green-yellow) compared to pleomorphic adenoma and mucous extravasation phenomenon (approximately 13% green-yellow) (p=0.001). Thick fiber distribution was similar in polymorphous low-grade adenocarcinoma and adenoid cystic carcinoma (p>0.05). We conclude that with picrosirius red staining and polarizing microscopy, stromal collagen fibers differ significantly in pleomorphic adenoma from those in polymorphous low-grade adenocarcinoma and adenoid cystic carcinoma, but not from mucous extravasation phenomenon. Similarity between polymorphous low-grade adenocarcinoma and adenoid cystic carcinoma may indicate that these tumor types represent a single entity with a broad spectrum of biological behavior.

Liposarcoma of the tongue: Clinico-pathologic correlations of a possible underdiagnosed entity

Liposarcoma (LS), one of the most common malignant tumors, is considered as a rarity in the oral cavity, the tongue being the most frequent site for its occurrence. The purpose of the present study was to review and analyze the clinico-pathologic correlations of 32 cases of LS of the tongue, including four new cases from the files of our department. A total of 32 cases of LS of the tongue were collected, 29 from a MEDLINE search of the English language literature (1966-2004). Since the histopathologic features of one of the four new cases have been presented previously, this case was counted only once. LS of the tongue is a tumor of adult and old age, with a mean age of approximately 62 years and a peak incidence in the seventh and eighth decades. Clinically, it is a long-standing tumor that commonly presents as a solitary nodular mass, but can also present as a multi-nodular lesion. The most common histopathologic type is that of atypical lipomatous tumor (ALT)/well-differentiated LS (75%). LS can be easily misdiagnosed with both benign and malignant lipomatous and non-lipomatous tumors. LS of the tongue was commonly treated by local excision, however, there were cases of (multiple) recurrences and dedifferentiation. When a lipomatous lesion is encountered in the oral cavity, and especially in the tongue, LS should certainly be among the lesions that top the list of differential diagnosis. The follow-up must be on a long-term basis since this tumor can recur years after initial surgical treatment and can also undergo dedifferentiation.