BACKGROUND: Canonical transient receptor potential channels play a crucial role in cancer cell proliferation. While TRPC6 subtype detection in submandibular glands and the relevance of some TRPC channels in this gland have been shown in animal models, its histological detection in human lacrimal and submandibular glands, as well as related tumors, lacks systematic study. Studying TRPC6 in humans could lead to new therapeutic options. This research aimed to immunohistochemically detect TRPC6 in human samples of physiological lacrimal and submandibular glands and of adenoid cystic carcinoma and mucoepidermoid carcinoma.
METHODS: Seven fixed body donors and samples of six cancer patients were examined. The ten tissue samples collected from the submandibular and lacrimal glands were then processed into histological slides and stained with hematoxylin-eosin. Tumor samples were provided as sections. TRPC6 presence was determined by immunohistochemistry, which was performed by indirect detection with a primary TRPC6 antibody, a secondary HRP-conjugated antibody and the chromogen diaminobenzidine.
RESULTS: Results confirm TRPC6 expression in all ten physiological gland samples: all samples showed a immunohistochemical signal with varying intensity. No significant gender-specific differences could be observed. TRPC6 was detected in four of six submandibular adenoid cystic carcinoma and the mucoepidermoid carcinoma samples, especially in tumor cells\' cytoplasma and nuclei. Excretory ducts consistently showed TRPC6. Mucous tubules, their nuclei and the nuclei of adipocytes generally showed no signal while serous acini and their nuclei showed a weak TRPC6 signal.
CONCLUSIONS: The discovery of TRPC6 in glandular tissue indicates a role in salivary gland function and calcium homeostasis is a basis for further research into its significance for tumor development in adenoid cystic carcinoma and mucoepidermoid carcinoma of salivary glands. TRPC6 could be used as a target for treatment of these tumors. However, the correlation between TRPC6 and submandibular and lacrimal gland diseases requires further exploration.

OBJECTIVE: To investigate prognostic factors in patients with head and neck Mucoepidermoid Carcinoma (MEC), especially the impact of treatment modalities on survival.
METHODS: Patients with primary head and neck MEC between 2000 and 2015 were obtained from the Surveillance, Epidemiology, and End Results (SEER) database. Prognostic factors related to Overall Survival (OS) and Cancer-Specific Survival (CSS), as well as the impact of treatments, were evaluated by multivariable Cox regression analysis.
RESULTS: We identified 2692 patients diagnosed with head and neck MEC, of whom 1397 (51.89%) had a parotid gland primary, 569 (22.14%) died, and 341 (12.67%) died of MEC. Older age (≥53 years), males, unmarried, lower income, tumor site in other head and neck areas, higher tumor grade, larger tumor size, and higher stage were related to poorer OS and CSS. Patients who did not undergo surgery (HR=3.20, 95% CI 2.45‒4.18) had worse OS, while no significant difference was detected between partial and total organ excision on patients\' OS (p=0.729). For combination therapy, patients who received radiotherapy only (HR=3.21, 95% CI 2.27-4.53) or no surgery and no radiotherapy (HR=2.59, 95% CI 1.83-3.67) were correlated with worse OS (vs. surgery only), but no significant difference was detected between surgery only and surgery combined with radiotherapy on patients\' OS (p=0.218). For CSS, the corresponding results were consistent with OS.
CONCLUSIONS: Surgical resection only may be a better survival option for head and neck MEC.

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The biological nature of salivary gland neoplasms and the overlapping characteristics that result from the heterogeneity of the cells of origin make diagnosis difficult. Hence, we intend to present a case of low grade mucoepidermoid carcinoma (MEC) on the palate and to understand the importance of biomarker such as p63 in the early diagnosis of tumor as it also has a role in its histogenesis. A 53-year-old female reported with a unilateral swelling for 3 months on posterolateral palatal region of the right side. Clinical differentials for such palatal swellings include a varied spectrum of lesions such as reactive, benign, and malignant lesions. Based on the incisional and excisional biopsy, histopathological findings and immunohistochemical examination with p63 the case were diagnosed with low grade MEC. The tumor cell differentiation in MEC could be the result of multiplicity of differentiation pathways leading to the formation of various histological patterns. This case report highlights the complexity of salivary gland pathology diagnosis and role of specific tumor marker such as p63 as an early marker for differentiation of salivary gland tumor such as low grade MEC from other cystic lesions occurring on the palate.

Warthin-like mucoepidermoid carcinoma (WL-MEC) is a newly reported variant of mucoepidermoid carcinoma. Its histological feature is easy to confused with metaplastic Warthin Tumor, and its relationship with Warthin tumor in histogenesis is controversial. In this study, we presented two cases of WL-MEC, discussing their clinicopathological and molecular features. Notably, one case was initially misdiagnosed during the first onset of the tumor. Case 1 was a 60-year-old female with a mass in the right parotid gland. Case 2 featured a 29-year-old male who developed a lump at the original surgical site 6 months after a \"Warthin tumor\" resection from the submandibular gland. Histologically, both tumor exhibited a prominent lymphoid stroma and cystic pattern, accompanied by various amounts of epithelial nests composed of squamoid cells, intermediate cells and mucinous cells. The characteristic eosinophilic bilayer epithelium of Warthin tumor was not typically presented in either case. Both cases tested positive for MAML2 gene rearrangement. To contextualize our findings, we conducted a comprehensive review of forty-eight WL-MEC cases documented in the English literature, aiming to synthesizing a reliable differential diagnostic approach. WL-MEC is a rare yet clinically relevant variant, posing a diagnostic pitfall for pathologists. Our study underscores the importance of a meticulous evaluation of both clinical and histological features, coupled with the detection of MAML2 rearrangement, as a credible method for distinguishing WL-MEC from other benign and malignant lesions, particularly metaplastic Warthin tumor.

Our goal was to assess the impact of childhood/adolescent cancer history on overall survival (OS) and disease-specific survival (DSS) in patients with parotid mucoepidermoid carcinoma (MEC). Patients who underwent surgical treatment for primary parotid MEC and those with a second malignancy of parotid MEC were retrospectively identified from the Surveillance, Epidemiology, and End Results (SEER) database. The primary outcome variables were OS and DSS. The hazard ratios (HRs) of these survival rates associated with cancer history were analysed using Cox regression models. In total, 2681 patients were included, 263 of whom had a second malignancy. The 10-year OS rates in the primary (72%) and second malignancy groups (59%) were significantly different. Cox regression confirmed that a history of cancer tended to decrease OS (p = 0.062, HR: 1.28, 95% confidence interval: 0.99 to 1.64). Subgroup analyses showed that a history of solid tumour as opposed to haematological cancer predicted worse OS, with central nervous system tumours exhibiting a more significant influence than others (p = 0.030 vs p = 0.088). Cancer history was not related to DSS. A history of childhood/adolescent cancer negatively influenced the prognosis of patients with parotid MEC, and this effect was primarily driven by a history of solid malignancy.

Mucoepidermoid carcinoma (MEC) is a salivary gland tumor commonly arising from the parotid gland. MEC has various presenting symptoms, including a painless, slow-growing mass below or anterior to the ear lobule. However, an unusual presentation can also be in the form of post-auricular swelling. Other more common benign differentials for post-auricular swelling include lymphadenopathy, epidermoid cysts, and lipomas. Thus, diagnosing a postauricular swelling as MEC solely based on clinical presentation is challenging, and a high suspicion, as well as a multidisciplinary approach with various radiological investigations such as computed tomography (CT) and magnetic resonance imaging (MRI), are required in collaboration with histopathological assessment for an accurate diagnosis of this malignancy. Prognosis depends on various factors, including the grade of the tumor, the patient\'s age, and comorbidities, as well as the stage at the time of diagnosis. Early diagnosis and surgical intervention are the mainstays of treatment, which can be followed by adjuvant radiotherapy based on the stage of the malignancy. This is a report of a patient who presented with post-auricular swelling, which was initially misdiagnosed as a benign necrotic lymph node. After further evaluation, it was found to be a mucoepidermoid carcinoma of the parotid gland, which was managed by surgical excision and radiotherapy.

Background and Objectives: Mucin has been implicated via various mechanisms in the development and growth of tumour cells. However, mucin expression studies in salivary gland tumours are limited, especially with samples from minor salivary glands. This study aims to investigate and compare mucin expression in benign and malignant salivary gland tumours of minor and major salivary gland origins. Materials and Methods: Special stains were used to stain neutral mucin (Periodic acid Schiff), sialomucin (Alcian Blue) and sulfomucin (Aldehyde Fuschin) within tissues from six normal salivary glands and 73 salivary gland tumours including 31 pleomorphic adenomas, 27 mucoepidermoid carcinomas, and 15 adenoid cystic carcinomas. A semi-quantitative approach was used to evaluate mucin expression within ductal lumens. Sialomucin was the most expressed mucin in all salivary gland tumours, regardless of origin. Results: A significant difference was observed in the mucin expression between benign and malignant salivary gland tumours, as pleomorphic adenoma showed three times significantly higher expression of sialomucin compared to mucoepidermoid carcinoma and adenoid cystic carcinoma (p = 0.028). Pleomorphic adenomas of major glands showed 42 times significantly higher expression of sialomucin compared to those of minor glands (p = 0.000). Conclusions: Sialomucin content in pleomorphic adenomas of major glands was vastly increased compared to that in minor glands. Differential sialomucin expression in benign and malignant salivary gland tumours suggests a role in diagnosing of borderline salivary gland tumours.

BACKGROUND: Salivary gland-type lung carcinomas are uncommon neoplasms of the lung, representing less than 1% of all lung tumors. The two most common among them are adenoid cystic carcinoma and mucoepidermoid carcinoma. Although they usually have an indolent behavior, adenoid cystic carcinomas can be more aggressive, with 5-year survival as low as 55%. Very few cases are reported in literature. We report a similar rare case of salivary gland type lung carcinoma that presented for the first time with unilateral opacification of left hemithorax.
METHODS: A 38-year-old man of North Indian origin, who was a a nonsmoker, presented with complaints of shortness of breath and cough for 1 year, which has increased in the last 2 months and was associated with significant weight loss. A frontal radiograph of the chest and computed tomography of the chest were performed, which showed a mass in the left upper lobe of the lung with its epicenter in the left main bronchus. A bronchoscopic guided biopsy was performed, and histopathology confirmed the diagnosis of lung carcinoma of salivary gland type (adenoid cystic carcinoma). There was invasion of major vessels, hence the patient was offered and started on palliative management instead of surgical treatment. In spite of palliative management of two cycles of chemotherapy and radiotherapy, the patient succumbed to the disease within 2 months from the time of diagnosis.
CONCLUSIONS: Lung carcinoma of the salivary gland type (especially adenoid cystic carcinoma) usually presents at a later stage. The resectability of the tumor depends on the involvement of the surrounding major vessels. Interestingly, these cancers have no association with smoking. The prognosis depends on the extent of the disease at the time of diagnosis. Hence, imaging plays a major role in deciding the further plan of management.

Hepatobiliary mucoepidermoid carcinoma is a rare malignant tumor comprising mucous, intermediate, and epidermoid cells. Herein, we presented a case of primary liver mucoepidermoid carcinoma preoperatively misdiagnosed as conventional intrahepatic cholangiocarcinoma. A 67-year-old male was admitted to our hospital. Preoperative laboratory tests showed increased aspartate transaminase, alanine transaminase, and carbohydrate antigen 19-9. Abdominal Computer Tomography revealed a 4.8 × 4.9 cm liver mass in segment VI. A preliminary diagnosis of intrahepatic cholangiocarcinoma was made, with undergoing partial hepatectomy. However, on histopathology, the tumor comprised a mixture of epidermoid, mucous, and intermediate cells with diffuse infiltrating at the tumor margin. On special stains, mucous and intermedia cells were positive for mucicarmine and Alcian blue, whereas epidermoid cells were positive for Keratin 5/6 and p63. Intermediate cells are also positive for p63. All tumor cells were positive for Keratin 7. The Ki-67 index was 35%. The final diagnosis was primary hepatic mucoepidermoid carcinoma. Although rare, hepatic mucoepidermoid carcinoma should be considered in the intrahepatic cholangiocarcinoma differential diagnosis. We reviewed previous studies and found that hepatobiliary mucoepidermoid carcinoma is more likely to originate from the biliary tract adjacent to the tumor.