Wnt/ß-catenin signal alteration and its diagnostic utility in basal cell adenoma and histologically similar tumors of the salivary gland.

Differential diagnosis among basal cell adenoma (BCA), basal cell adenocarcinoma (BCAC), adenoid cystic carcinoma (ACC) and pleomorphic adenoma (PA) of the salivary gland can be challenging due to their similar histological appearance. Although frequent nuclear ß-catenin expression and CTNNB1 mutations have been reported in BCA, further details of the Wnt/ß-catenin signal alterations are unclear. The aim of this study was to assess the diagnostic utility of Wnt/ß-catenin signal alteration in BCA and morphological mimics. We performed immunohistochemical staining for ß-catenin and mutation analysis for Wnt/ß-catenin-related genes (CTNNB1, APC, AXIN1 and AXIN2) in BCA (n = 34), BCAC (n = 3), ACC (n = 67) and PA (n = 31). We also analyzed ACC-specific MYB and MYBL1 gene rearrangements by fluorescence in situ hybridization (FISH). Nuclear ß-catenin expression (≥3%) was present in 32/34 cases (94.1%) of BCA, and the nuclear ß-catenin labeling index was significantly higher than in other tumor types (p = < 0.0001). In BCA, we found mutations in CTNNB1, APC and AXIN1 genes (41.1%, 2.9% and 8.8%, respectively). In BCAC, nuclear ß-catenin expression with CTNNB1 mutation was present in 1/3 cases (33.3%). As for ACC, nuclear ß-catenin expression was observed in 3/67 cases (4.4%), but all 3 cases harbored either MYB or MYBL1 gene rearrangement. The results suggest that nuclear ß-catenin immunoreactivity with appropriate criteria may be helpful to distinguish BCA from histologically similar tumors. However, a minor subset of ACCs with nuclear ß-catenin expression require careful diagnosis. In addition, Wnt/ß-catenin signal alteration may play a role in the pathogenesis of BCA and BCAC.

Low-grade intraductal carcinoma (low-grade cribriform cystadenocarcinoma) with tumor-associated lymphoid proliferation of parotid gland.

We report a rare case of low-grade intraductal carcinoma with tumor-associated lymphoid proliferation (TALP) in the parotid gland of a 75-year-old woman. Grossly, the tumor was solid and cystic. Histologically, the tumor consisted of a papillary-cystic, micropapillary, or focally cribriform proliferations of epithelial cells with low-grade cytological atypia. The interspaces between the epithelial components were filled with prominent lymphoid stroma and lymphoid follicles, superficially mimicking Warthin tumor. The neoplastic epithelial cells were positive for S100 protein by immunohistochemical staining. There was an attenuated layer of myoepithelial cells all around the epithelial components, indicating a non-invasive (in situ) nature. Although TALP is a rare finding in intraductal carcinoma, it should be considered as a histological variation of this kind of tumor. The relationship between intraductal carcinoma, low-grade cribriform cystadenocarcinoma, low-grade salivary duct carcinoma, and salivary duct carcinoma in situ is also discussed in this report.

Long-term outcomes of type I thyroplasty with silicone implantation: Assessment of excised laryngeal tissue from a patient with secondary hypopharyngeal carcinoma.

Here we describe the long-term outcomes of type I thyroplasty (TP-I) with silicone block implantation through histopathological assessments in a male patient who underwent pharyngolaryngectomy for secondary hypopharyngeal carcinoma 7 years after silicone implantation. A 66-year-old man presented with esophageal carcinoma and underwent subtotal esophagotomy. Subsequently, his left vocal fold exhibited fixation in a paramedian position, and he underwent TP-I with silicone block implantation 2 years after the primary esophageal surgery. His voice quality improved; however, he developed glottic carcinoma in the right vocal fold 6 months after TP-I and underwent laser cordectomy. Glottic carcinoma recurred 21 months later, and he underwent laser cordectomy again. Five years after the second laser surgery, he underwent pharyngolaryngectomy and neck dissection for hypopharyngeal carcinoma detected in the right pyriform sinus. We histopathologically examined a horizontal section of the resected larynx to assess silicone implant-related changes. Although migration of the silicone implant was not observed, a very mild foreign body reaction occurred around the implant. The patient is currently in remission. Our findings suggest that silicone implants are suitable for TP-I due to their remarkable affinity for human tissue and the low risk of a tissue reaction.

Molecular subclassification determined by human papillomavirus and epidermal growth factor receptor status is associated with the prognosis of oropharyngeal squamous cell carcinoma.

Human papillomavirus (HPV) infection is an indicator of good response to chemoradiotherapy in oropharyngeal squamous cell carcinoma (OPSCC), and epidermal growth factor receptor (EGFR) is a molecular-therapeutic target in head and neck squamous cell carcinoma. Here we investigated the prevalence and prognostic significance of HPV infection and EGFR alteration in OPSCC. We analyzed the presence of high-risk HPV using in situ hybridization, protein expressions of p16 and EGFR using immunohistochemistry, and the EGFR gene copy number gain using chromogenic in situ hybridization (CISH) in 105 cases of OPSCC. The biopsy specimens before chemoradiotherapy were used for these analyses. HPV infection and p16 protein overexpression were detected in 53.3% and 52.4% of the OPSCCs, and each factor was associated with better overall survival (P = .0026 and P = .0026) and nonkeratinizing histology (P = .0002 and P = .0004), respectively. EGFR gene copy number gain (high polysomy or amplification) was detected in 12.4% of the OPSCCs and was correlated with EGFR protein overexpression (P = .0667) and worse overall survival (P < .0001). HPV infection and EGFR gene copy number gain (EGFR CISH positive) were mutually exclusive. The HPV-negative/EGFR CISH-positive OPSCCs had significantly worse overall survival than did the HPV-positive/EGFR CISH-negative OPSCCs and HPV-negative/EGFR CISH-negative OPSCCs (P < .0001 and P < .0001, respectively). The EGFR CISH-negative OPSCCs had favorable prognosis irrespective of HPV infection. Our results suggest that EGFR gene copy number gain-positive tumors represent an HPV-negative, aggressive subgroup of OPSCCs. The molecular subclassification of OPSCCs based on HPV infection and EGFR status may serve as important information for appropriate therapeutic strategy.

Dual gain of HER2 and EGFR gene copy numbers impacts the prognosis of carcinoma ex pleomorphic adenoma.

We investigated the potential roles of HER2 and EGFR and evaluated their prognostic significance in carcinoma ex pleomorphic adenoma (CXPA). We analyzed HER2 and EGFR overexpression status using immunohistochemistry (IHC) and gene copy number gain by chromogenic in situ hybridization (CISH) in 50 cases of CXPA (40 ductal-type and 10 myoepithelial-type CXPAs). Salivary duct carcinoma was the most common histologic subtype of malignant component (n = 21). Immunohistochemistry positivity and chromogenic in situ hybridization positivity were closely correlated in both HER2 and EGFR. HER2 CISH positivity (mostly gene amplification) and EGFR CISH positivity (mostly gene high polysomy) were present in 19 (40%) and 21 (44%) cases, respectively, and were each significantly correlated with poor outcome (P = .0009 and P = .0032, respectively). Dual gain of HER2 and EGFR gene copy numbers was present in 11 cases (23%) and was the most aggressive genotype. HER2 CISH positivity was more frequently present in ductal-type CXPAs (47%) than in myoepithelial-type CXPAs (10%), whereas the prevalence of EGFR CISH positivity was similar in both histologic subtypes (42% and 50%, respectively). Our results suggest that HER2 and EGFR gene copy number gains may play an important role in the progression of CXPA, in particular ductal-type CXPAs. HER2 CISH-positive/EGFR CISH-positive tumors may be the most aggressive subgroup in CXPA. The molecular subclassification of CXPA based on the HER2 and EGFR status may be helpful for prognostic prediction and decisions regarding the choice of therapeutic strategy.

Hyalinizing clear cell carcinoma with EWSR1-ATF1 fusion gene: report of three cases with molecular analyses.

Hyalinizing clear cell carcinoma (HCCC) is a low-grade salivary gland carcinoma characterized by clear cells and hyalinized stroma. Recently, the EWSR1-ATF1 fusion gene was found in HCCCs. We herein describe three cases of HCCC identified in one male and two females, ranging in age from 27 to 67 years. The tumors were located in the root of tongue, nasopharynx, and soft palate. They were composed of nested or cord-like proliferations of epithelial cells with clear to pale eosinophilic cytoplasm, embedded in hyalinized and focally fibroedematous stroma. Tumor-associated lymphoid proliferation and pseudoepitheliomatous hyperplasia were also observed in each one case. MAML2 fusions specific to mucoepidermoid carcinoma were not detected in any of the three cases. We found EWSR1-ATF1 in two of three HCCCs using reverse transcription polymerase chain reaction (RT-PCR) with our original primer sets designed to detect the fusion gene transcripts in formalin-fixed paraffin-embedded (FFPE) tissues. EWSR1 rearrangement was also confirmed by fluorescence in situ hybridization (FISH) on FFPE sections in two cases. There was a good concordance between the two methods (two positive cases and one negative case by both RT-PCR and FISH). Therefore, RT-PCR and FISH using FFPE tissue may be ancillary tools to confirm the diagnosis of HCCC.