Mucosal Soft Tissue Lesions.

Mucosal soft tissue lesions are fairly common in the pediatric population. However, the precise prevalence is unknown. This is the result of the limited number of studies, the use of various diagnostic criteria in those studies, and the transient nature of commonly encountered lesions in this population. In this section, we seek to familiarize the pediatric pathologist with a sampling of mucosal soft tissue lesions encountered in pediatric patients, highlight key diagnostic features and correlations with systemic diseases should they exist.

Histone methylation antagonism drives tumor immune evasion in squamous cell carcinomas.

How cancer-associated chromatin abnormalities shape tumor-immune interaction remains incompletely understood. Recent studies have linked DNA hypomethylation and de-repression of retrotransposons to anti-tumor immunity through the induction of interferon response. Here, we report that inactivation of the histone H3K36 methyltransferase NSD1, which is frequently found in squamous cell carcinomas (SCCs) and induces DNA hypomethylation, unexpectedly results in diminished tumor immune infiltration. In syngeneic and genetically engineered mouse models of head and neck SCCs, NSD1-deficient tumors exhibit immune exclusion and reduced interferon response despite high retrotransposon expression. Mechanistically, NSD1 loss results in silencing of innate immunity genes, including the type III interferon receptor IFNLR1, through depletion of H3K36 di-methylation (H3K36me2) and gain of H3K27 tri-methylation (H3K27me3). Inhibition of EZH2 restores immune infiltration and impairs the growth of Nsd1-mutant tumors. Thus, our work uncovers a druggable chromatin cross talk that regulates the viral mimicry response and enables immune evasion of DNA hypomethylated tumors.

Alcohol Metabolism Enriches Squamous Cell Carcinoma Cancer Stem Cells That Survive Oxidative Stress via Autophagy.

BACKGROUND: Alcohol (ethanol) consumption is a major risk factor for head and neck and esophageal squamous cell carcinomas (SCCs). However, how ethanol (EtOH) affects SCC homeostasis is incompletely understood. METHODS: We utilized three-dimensional (3D) organoids and xenograft tumor transplantation models to investigate how EtOH exposure influences intratumoral SCC cell populations including putative cancer stem cells defined by high CD44 expression (CD44H cells). RESULTS: Using 3D organoids generated from SCC cell lines, patient-derived xenograft tumors, and patient biopsies, we found that EtOH is metabolized via alcohol dehydrogenases to induce oxidative stress associated with mitochondrial superoxide generation and mitochondrial depolarization, resulting in apoptosis of the majority of SCC cells within organoids. However, CD44H cells underwent autophagy to negate EtOH-induced mitochondrial dysfunction and apoptosis and were subsequently enriched in organoids and xenograft tumors when exposed to EtOH. Importantly, inhibition of autophagy increased EtOH-mediated apoptosis and reduced CD44H cell enrichment, xenograft tumor growth, and organoid formation rate. CONCLUSIONS: This study provides mechanistic insights into how EtOH may influence SCC cells and establishes autophagy as a potential therapeutic target for the treatment of EtOH-associated SCC.

Treatment of recurrent mucosal melanoma of the oral cavity with topical imiquimod and pembrolizumab achieves complete histopathologic remission.

Mucosal melanomas constitute a subtype of melanoma with less effective treatments than cutaneous melanomas. We present a case of oral mucosal melanoma that recurred despite multiple resections and adjuvant temozolomide. Treatment with topical imiquimod combined with pembrolizumab achieved remission. A 56-year-old woman presented with a pigmented mass on her left anterior hard palate. Biopsy revealed malignant melanoma. The patient had resection with neck dissection with 3 months of adjuvant temozolomide due to positive margins. Malignant melanoma involving the hard palate recurred 1 year later requiring additional resection. Two years later, two additional pigmented lesions were found; further resections were deferred due to expected morbidity. Following 6 weeks of topical imiquimod treatment, the lesions shrunk significantly. Adjuvant pembrolizumab was added and complete histopathologic remission was observed in 6 months. The patient remained in remission for 4 years before new melanoma in situ was diagnosed, requiring five additional months of imiquimod. As of April 2021, there is no clinical evidence of melanoma. There are limited reports of oral melanoma treated with topical imiquimod. Here, imiquimod administered in combination with pembrolizumab achieved complete pathologic response.

The REASON score: an epigenetic and clinicopathologic score to predict risk of poor survival in patients with early stage oral squamous cell carcinoma.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is a capricious cancer with poor survival rates, even for early-stage patients. There is a pressing need to develop more precise risk assessment methods to appropriately tailor clinical treatment. Genome-wide association studies have not produced a viable biomarker. However, these studies are limited by using heterogeneous cohorts, not focusing on methylation although OSCC is a heavily epigenetically-regulated cancer, and not combining molecular data with clinicopathologic data for risk prediction. In this study we focused on early-stage (I/II) OSCC and created a risk score called the REASON score, which combines clinicopathologic characteristics with a 12-gene methylation signature, to predict the risk of 5-year mortality. METHODS: We combined data from an internal cohort (n = 515) and The Cancer Genome Atlas (TCGA) cohort (n = 58). We collected clinicopathologic data from both cohorts to derive the non-molecular portion of the REASON score. We then analyzed the TCGA cohort DNA methylation data to derive the molecular portion of the risk score. RESULTS: 5-year disease specific survival was 63% for the internal cohort and 86% for the TCGA cohort. The clinicopathologic features with the highest predictive ability among the two the cohorts were age, race, sex, tobacco use, alcohol use, histologic grade, stage, perineural invasion (PNI), lymphovascular invasion (LVI), and margin status. This panel of 10 non-molecular features predicted 5-year mortality risk with a concordance (c)-index = 0.67. Our molecular panel consisted of a 12-gene methylation signature (i.e., HORMAD2, MYLK, GPR133, SOX8, TRPA1, ABCA2, HGFAC, MCPH1, WDR86, CACNA1H, RNF216, CCNJL), which had the most significant differential methylation between patients who survived vs. died by 5 years. All 12 genes have already been linked to survival in other cancers. Of the genes, only SOX8 was previously associated with OSCC; our study was the first to link the remaining 11 genes to OSCC survival. The combined molecular and non-molecular panel formed the REASON score, which predicted risk of death with a c-index = 0.915. CONCLUSIONS: The REASON score is a promising biomarker to predict risk of mortality in early-stage OSCC patients. Validation of the REASON score in a larger independent cohort is warranted.

MicroRNA-Based Cancer Mortality Risk Scoring System and hTERT Expression in Early-Stage Oral Squamous Cell Carcinoma.

We have previously constructed a novel microRNA (miRNA)-based prognostic model and cancer-specific mortality risk score formula to predict survival outcome in oral squamous cell carcinoma (OSCC) patients who are already categorized into "early-stage" by the TNM staging system. A total of 836 early-stage OSCC patients were assigned the mortality risk scores. We evaluated the efficacy of various treatment regimens in terms of survival benefit compared to surgery only in patients stratified into high (risk score ≥0) versus low (risk score <0) mortality risk categories. For the high-risk group, surgery with neck dissection significantly improved the 5-year survival to 75% from 46% with surgery only (p < 0.001); a Cox proportional hazard model on time-to-death demonstrated a hazard ratio of 0.37 for surgery with neck dissection (95% CI: 0.2-0.6; p=0.0005). For the low-risk group, surgery only was the treatment of choice associated with 5-year survival benefit. Regardless of treatment selected, those with risk score ≥2 may benefit from additional therapy to prevent cancer relapse. We also identified hTERT (human telomerase reverse transcriptase) as a gene target common to the prognostic miRNAs. There was 22-fold increase in the hTERT expression level in patients with risk score ≥2 compared to healthy controls (p < 0.0005). Overexpression of hTERT was also observed in the patient-derived OSCC organoid compared to that of normal organoid. The DNA cancer vaccine that targets hTERT-expressing cells currently undergoing rigorous clinical evaluation for other tumors can be repurposed to prevent cancer recurrence in these high-risk early-stage oral cancer patients.

Generation and Characterization of Patient-Derived Head and Neck, Oral, and Esophageal Cancer Organoids.

Esophageal cancers comprise adenocarcinoma and squamous cell carcinoma, two distinct histologic subtypes. Both are difficult to treat and among the deadliest human malignancies. We describe protocols to initiate, grow, passage, and characterize patient-derived organoids (PDO) of esophageal cancers, as well as squamous cell carcinomas of oral/head-and-neck and anal origin. Formed rapidly (<14 days) from a single-cell suspension embedded in basement membrane matrix, esophageal cancer PDO recapitulate the histology of the original tumors. Additionally, we provide guidelines for morphological analyses and drug testing coupled with functional assessment of cell response to conventional chemotherapeutics and other pharmacological agents in concert with emerging automated imaging platforms. Predicting drug sensitivity and potential therapy resistance mechanisms in a moderate-to-high throughput manner, esophageal cancer PDO are highly translatable in personalized medicine for customized esophageal cancer treatments. © 2020 by John Wiley & Sons, Inc. Basic Protocol 1: Generation of esophageal cancer PDO Basic Protocol 2: Propagation and cryopreservation of esophageal cancer PDO Basic Protocol 3: Imaged-based monitoring of organoid size and growth kinetics Basic Protocol 4: Harvesting esophageal cancer PDO for histological analyses Basic Protocol 5: PDO content analysis by flow cytometry Basic Protocol 6: Evaluation of drug response with determination of the half-inhibitory concentration (IC50 ) Support Protocol: Production of RN in HEK293T cell conditioned medium.

PIK3CA and p53 Mutations Promote 4NQO-Initated Head and Neck Tumor Progression and Metastasis in Mice.

The PI3K signaling pathway is frequently mutated in head and neck squamous cell carcinoma (HNSCC), often via gain-of-function (GOF) mutations in the PIK3CA gene. Here, we present novel genetically engineered mouse models (GEMM) carrying a GOF allele Loxp-STOP-Loxp(LSL)-PIK3CAH1047R (E20) alone or in combination with heterozygous LSL-p53+/R172H (p53) mutation with tissue-specific expression to interrogate the role of oncogenic PIK3CA in transformation of upper aerodigestive track epithelium. We demonstrated that the GOF PIK3CA mutation promoted progression of 4-nitroquinoline 1-oxide-induced oral squamous cell carcinoma (OSCC) in both E20 single mutant and E20/p53 double mutant mice, with frequent distal metastasis detected only in E20/p53 GEMM. Similar to in human OSCC, loss of p16 was associated with progression of OSCC in these mice. RNA-seq analyses revealed that among the common genes differentially expressed in primary OSCC cell lines derived from E20, p53, and E20/p53 GEMMs compared with those from the wild-type mice, genes associated with proliferation and cell cycle were predominantly represented, which is consistent with the progressive loss of p16 detected in these GEMMs. Importantly, all of these OSCC primary cell lines exhibited enhanced sensitivity to BYL719 and cisplatin combination treatment in comparison with cisplatin alone in vitro and in vivo, regardless of p53 and/or p16 status. Given the prevalence of mutations in p53 and the PI3K pathways in HNSCC in conjunction with loss of p16 genetically or epigenetically, this universal increased sensitivity to cisplatin and BYL719 combination therapy in cancer cells with PIK3CA mutation represents an opportunity to a subset of patients with HNSCC. IMPLICATIONS: Our results suggest that combination therapy of cisplatin and PI3K inhibitor may be worthy of consideration in patients with HNSCC with PIK3CA mutation.

MicroRNA-based risk scoring system to identify early-stage oral squamous cell carcinoma patients at high-risk for cancer-specific mortality.

BACKGROUND: For early-stage oral squamous cell carcinoma (OSCC), there is no existing risk-stratification modality beyond conventional TNM staging system to identify patients at high risk for cancer-specific mortality. METHODS: A total of 568 early-stage OSCC patients who had surgery only and also with available 5-year clinical outcomes data were identified. Signature microRNAs (miRNAs) were discovered using deep sequencing analysis and validated by qRT-PCR. The final 5-plex prognostic marker panel was utilized to generate a cancer-specific mortality risk score using the multivariate Cox regression analyses. The prognostic markers were validated in the internal and external validation cohorts. RESULTS: The risk score from the 5-plex marker panel consisting of miRNAs-127-3p, 4736, 655-3p, TNM stage and histologic grading stratified patients into four risk categories. Compared to the low-risk group, the high-risk group had 23-fold increased mortality risk (hazard ratio 23, 95% confidence interval 13-42), with a median time-to-recurrence of 6 months and time-to-death of 11 months (vs >60 months for each among low-risk patient; p < .001). CONCLUSION: The miRNA-based 5-plex marker panel driven mortality risk score formula provides clinically practical and reliable measures to assess the prognosis of patients assigned to an early-stage OSCC.

Stafne Bone Defect Involving the Ascending Ramus.

The Stafne bone defect (SBD) classically presents as a well-defined, radiolucent lesion in the molar-mandibular angle region beneath the level of the mandibular canal. Due in large part to this prototypical appearance, most cases of SBDs are radiographically diagnostic without the need for tissue biopsy. A diagnostic challenge may arise, however, when the SBD occurs in other locations in the mandible. The authors report a case of a 57-year-old male who presented with a SBD of the left ascending ramus. The lesion was found incidentally on a panoramic radiograph. Additional imaging studies confirmed a lingual concavity of the mandibular bone consistent with a SBD, and a retrospective study of the patient's records revealed the presence of the lesion 5 years prior without any radiographic alterations. To date, only 10 documented cases of an SBD involving the ascending ramus have been reported. The rarity of such a presentation may obscure the diagnosis and lead to unwarranted surgical procedures. It is important to recognize atypically located SBDs, because unlike other radiolucent lesions, imaging studies are diagnostic. With proper diagnosis, additional surgical procedures and any associated morbidities can be avoided.

Ameloblastic Fibro-Odontoma in an Adolescent: A Case Report and Review of Literature.

Ameloblastic fibro-odontoma (AFO) is a rare benign odontogenic tumor with the histologic features of ameloblastic fibroma (AF) but also contains enamel and dentin. It is most commonly observed in the pediatric population. Distinction between AFO and AF becomes important as ameloblastic fibromas are associated with higher recurrence rates of up to 18%, and 35% of these recurrent lesions can undergo malignant transformation to ameloblastic fibrosarcoma. Hence, for amelobastic fibroma, conservative curettage is recommended for the initial lesion and marginal resection is considered for recurrent cases. In contrast, AFO can be treated with simple curettage and the recurrence rate is approximately seven percent. Malignant transformation of AFO is exceedingly rare. Therefore, the treatment and prognosis differs for these two histologically similar neoplasms. We present a case of a 17-year-old boy who was initially diagnosed with ameloblastic fibroma upon biopsy, with subsequent curettage specimen showing AFO, which carries a better prognosis.

Pyogenic Granuloma in the Tongue in a Five Year Old: A Case Report.

Pyogenic granuloma, also called lobular capillary hemangioma, is a benign vascular lesion of the skin and mucous membranes. While the majority of pyogenic granulomas in the oral cavity involve the gingiva, they also infrequently present at other sites including lips, oral mucosa, palate, and tongue. We report a case of a pyogenic granuloma of the tongue in a five-year old female patient.

Renal cell carcinoma metastatic to the maxillary gingiva: A case report and review of the literature.

Tumor metastasis to the oral cavity is rare and is usually an indication of late-stage disease and poor prognosis. While, there are reports of renal cell carcinoma (RCC) metastatic to oral cavity, vast majority of them are to the jaw. Herein, we present a case of a 78-year-old woman with RCC metastasis limited to the oral soft tissue without any bone involvement. As the lesion solely involved maxillary gingiva, it clinically mimicked that of a pyogenic granuloma, which is a reactive, nonneoplastic condition. This case was further complicated as the patient was unaware of primary cancer and appeared to be in good physical health. Her oral metastasis marked the initial manifestation of an otherwise silent primary renal cancer.

Oral manifestations of lipoid proteinosis in a 10-year-old female: A case report and literature update.

Lipoid proteinosis (LP) is a rare autosomal recessive disorder characterized by the deposition of amorphous hyaline material in the dermis and submucosal connective tissue. Here, we present a case of LP with significant oral, dermatologic, and neurologic manifestations occurring in a 10 year-old female of Asian descent. In addition to the more typical oral findings of restricted tongue movement and labial and buccal mucosal involvement, this case highlights an unusual pattern of gingival enlargement infrequently reported in the literature. As LP almost always involves the oral cavity, often before the onset of cutaneous lesions, it is important for dental providers to be familiar with the oral manifestations of this disease. Early detection and diagnosis of LP by the dental practitioner can help expedite proper multidisciplinary care and lead to significant reductions in patient morbidity and mortality.

Lingual Osseous Choristoma of the Tongue Base: Unusual Presentation of a Rare Entity.

Osseous lesions of the tongue, also referred to as osseous choristomas, are benign growths of bony tissue. These lesions are not true neoplasms but rather represent growth of normal tissue at an abnormal location. Clinically, they appear as exophytic masses of the tongue, and they are treated by surgical excision. Lingual osseous choristomas are rare entities, with only 71 reported cases in the literature. We present the case of a lingual osseous choristoma of the tongue base in a 21-year-old female. Of the cases of lingual osseous choristoma reported in the literature, ours is only the fifth case to involve this location.

Mandibular embryonal rhabdomyosarcoma with cartilaginous metaplasia: report of a case and review of literature.

Rhabdomyosarcoma (RMS) is a malignant tumor of skeletal muscle origin and frequently involves the head and neck region. It represents the second most common pediatric soft tissue sarcoma and accounts for 3% of all childhood cancers. Here, we report a case of embryonal RMS presenting as a right-sided facial swelling in a 7-year-old boy. Histologically, the tumor consisted of classic embryonal rhabdosarcomatous areas with metaplastic cartilage, in both initial biopsy and final resection specimens. Cartilaginous metaplasia arising in the background of RMS is a rare finding, thus raising a diagnostic challenge. To the best of our knowledge, this represents the first case of RMS with cartilaginous metaplasia in the oral cavity.

Langerhans Cell Histiocytosis Mimicking Periapical Pathology in a 39-year-old Man.

Langerhans cell histiocytosis (LCH) is a clonal neoplastic proliferation of Langerhans-type dendritic cells, with more than 50% of cases of LCH seen in children younger than 15 years of age. The most common clinical presentation of LCH is solitary or multiple bony lesions. The jaws are affected in approximately 10%-20% of cases, with a strong predilection for the mandible. The maxilla is involved in only 1% of head and neck cases. When the jaws are involved, lesions of LCH may mimic periapical pathology as seen in patients requiring endodontic therapy or bone loss as seen in periodontal disease. We report the case of a 39-year-old man with LCH involving the posterior maxilla. This is a rare presentation of LCH with respect to both location and patient age. Clinicians should consider LCH when developing a differential diagnosis of an apical radiolucency of vital teeth or teeth that fail to respond to endodontic therapy and be aware of its clinical and radiographic mimics.