Salivary duct carcinoma with squamous differentiation: histomorphological and immunophenotypical analysis of six cases.

Background And Aims: Salivary duct carcinoma (SDC) is an aggressive salivary malignancy with multiple morphological subtypes. Primary salivary squamous cell carcinoma (SCC) requires exclusion of high-grade salivary malignancies and metastatic disease and is considered exceptionally rare. We report six cases of SDC with resemblance to SCC on account of variable, but often extensive, squamous differentiation.

Extramammary Paget Disease of Oral Mucosa: Case Report with Literature Review.

Extramammary Paget disease (EPMD) of the oral mucosa is an unusual and extremely rare condition, with fewer than ten cases documented. Here, we report a case of EMPD extensively involving oral mucosa and underlying salivary ducts in a 72-year-old male and review published clinical, histologic, immunophenotypic, and prognostic features of this rare entity.

An Unusual Gingival (Peripheral) Tumor with Features of Keratoameloblastoma with Cytologic Atypia or Possible Malignant Transformation Exhibiting ARID1A Mutation.

Background: Keratoameloblastoma is a poorly characterized and rarely reported odontogenic neoplasm that can exhibit overlapping histopathologic features with conventional ameloblastoma and keratocystic odontogenic tumor (KCOT), with an ambiguous relationship to the so-called solid KCOT.

Methods: A peripheral maxillary tumor causing bone saucerization in a 54-year-old male is described and investigated with immunohistochemistry and Next-Generation Sequencing (NGS).

Results: Microscopically, the tumor comprised of a predominantly plexiform proliferation of odontogenic epithelium with central keratinization and evidence of surface origin.

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

Ameloblastoma is a benign, locally aggressive odontogenic neoplasm with variable solid and cystic morphology. On account of its histologic variety, diagnostically challenging cases can bear resemblance to odontogenic keratocyst/keratocystic odontogenic tumor (KCOT) or dentigerous cyst (DC). BRAF mutation has been reported to be specific for and frequent in ameloblastoma, and this study evaluated the usefulness of immunohistochemistry (IHC) using the BRAF VE1 mutant-specific antibody as a diagnostic adjunct in this setting.

Giant Cell Lesions of the Jaws Involving RASopathy Syndromes.

Objective: Giant cell lesions of the jaws (GCLJ) may rarely occur in the setting of RASopathy syndromes such as Noonan syndrome or neurofibromatosis I. Recently, central giant cell granulomas (CGCG), the most common of the GCLJ, have been recognized as benign neoplasms characterized by Ras/MAPK signaling pathway mutations. This provides a rational basis for understanding GCLJ in RASopathy syndromes as syndromically occurring CGCG.

Malignant Transformation Rate of Non-reactive Oral Hyperkeratoses Suggests an Early Dysplastic Phenotype.

The presence of epithelial dysplasia (ED) in oral leukoplakia is the single most important predictor of malignant transformation (MT). The majority of leukoplakias, however, do not show evidence of ED and yet MT of these lesions is well-recognized. These lesions have been referred to as "hyperkeratosis/hyperplasia, no dysplasia," "keratosis of unknown significance" and "hyperkeratosis, not reactive (HkNR).

Diatoms: A novel cause of granulomatous inflammation of the head and neck.

Objective: We report the first 4 cases of intraoral nonnecrotizing granulomatous foreign body reactions to diatoms, plausibly as a result of exogenous material introduced following iatrogenic or traumatic injury.

Study Design: Clinical and histopathologic findings of 4 intraoral cases of nonnecrotizing granulomatous foreign body reaction to diatoms, single-celled algae belonging to the taxonomic phylum Bacillariophyta, are reported.

Results: The lesions presented either in the jaws or in the soft tissue overlying the alveolar bone, in some instances mimicking an inflammatory lesion of odontogenic etiology.

Biallelic PTCH1 Inactivation Is a Dominant Genomic Change in Sporadic Keratocystic Odontogenic Tumors.

Keratocystic odontogenic tumors (KCOTs) are locally aggressive odontogenic neoplasms with recurrence rates of up to 60%. Approximately 5% of KCOTs are associated with nevoid basal cell carcinoma (Gorlin) syndrome and 90% of these show genomic inactivation of the PTCH1 gene encoding Patched 1. Sporadic KCOTs reportedly have PTCH1 mutations in 30% of cases, but previous genomic analyses have been limited by low tumor DNA yield.

Lipomas of the Oral Cavity: Utility of MDM2 and CDK4 in Avoiding Overdiagnosis as Atypical Lipomatous Tumor.

Traumatized lipomas with degenerative change may demonstrate histopathologic features that mimic atypical lipomatous tumor (ALT). Previously reported series of ALT involving the oral cavity preceded routine use of MDM2 and CDK4 immunohistochemistry. Our aim is to evaluate MDM2 and CDK4 immunohistochemical expression in adipocytic tumors arising in this site, in conjunction with the histiocytic marker PU.

Intraoral Salivary Duct Cyst: Clinical and Histopathologic Features of 177 Cases.

The salivary duct cyst (SDC) is a reactive ductal ectasia most frequently seen in major salivary glands, and likely caused by obstruction. The aim of this study is to define the clinical and histopathologic spectrum of intraoral SDCs. Cases were retrieved from the archives of Harvard School of Dental Medicine/StrataDx, Inc.

Human papillomavirus and Epstein-Barr virus associated conditions of the oral mucosa.

Human papillomavirus (HPV) and Epstein-Barr virus (EBV) infections of the oral mucosa may present as both benign and malignant conditions. Squamous papilloma, verruca vulgaris, and condyloma acuminatum are benign, HPV-associated growths treated with simple excision while multifocal epithelial hyperplasia (Heck disease) usually occurs in children and adolescents and resolves over time. HPV-associated oral dysplasia is uncommon and HPV-carcinoma comprises 6% of oral squamous cell carcinomas.