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.

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.

暂无摘要。

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) typically manifests in the salivary glands, but occurrences in the pancreatic gland are exceedingly rare. Surgical resection proves effective; however, pancreatic MEC is prone to metastasis, and lacking a standardized postoperative treatment. We discussed the experience of a 51-year-old female patient with pancreatic MEC who received paclitaxel and gemcitabine as postoperative care. Within a predetermined amount of time, this regimen successfully stopped the spread of metastatic tumors and returned tumor markers to normal. A Stable Disease status was achieved within 6 months after chemotherapy. In summary, gemcitabine and paclitaxel display efficacy in treating pancreatic MEC.

The survival significance of the number of positive lymph nodes in salivary gland carcinoma remains unclear. Thus, the current study aimed to determine the effect of the number of positive lymph nodes on disease-specific survival (DSS) and overall survival (OS) in cN0 mucoepidermoid carcinoma (MEC) of the major salivary gland. Patients surgically treated for MEC of the major salivary gland between 1975 and 2019 were retrospectively enrolled from the surveillance, epidemiology, and end results database. The total population was randomly divided into training and test groups (1:1). Primary outcome variables were DSS and OS. Prognostic models were constructed based on the independent prognostic factors determined using univariate and multivariate Cox analyses in the training group and were validated in the test group using C-index. A total of 3317 patients (1624 men and 1693 women) with a mean age of 55 ± 20 years were included. The number of positive lymph nodes was an independent prognostic factor for both DSS and OS, but the effect began when at least two positive lymph nodes for DSS and three positive lymph nodes for OS were found. Predictive models for DSS and OS in the training group had C-indexes of 0.873 (95% confidence interval [CI] 0.853-0.893) and 0.835 (95% CI 0.817-0.853), respectively. The validation of the test group showed C-indexes of 0.877 (95% CI 0.851-0.902) for DSS and 0.820 (95% CI 0.798-0.842) for OS. The number of positive lymph nodes was statistically associated with survival in cN0 major salivary gland MEC. The current prognostic model could provide individualized follow-up strategies for patients with high reliability.

暂无摘要。

Warthin-like mucoepidermoid carcinoma (MEC) is a recently identified MEC variant of the salivary gland. MEC morphologically mimics Warthin tumor (WT) but harbors the same chromosomal translocation t (11; 19) (q21; p13) as MEC. Thus, differential diagnosis is crucial. MEC involving WT is extremely rare in salivary glands. In this study, we reported a case of Warthin-like MEC, a case of MEC co-existing with WT, and a case of mucinous metaplasia in WT. We also discussed the possible link between WT and MEC.
Warthin样黏液表皮样癌是一种新近发现的涎腺黏液表皮样癌亚型，形态类似于Warthin瘤，但具有与黏液表皮样癌相似的t（11；19）（q21；p13）染色体易位。因此鉴别诊断非常重要。Warthin瘤合并黏液表皮样癌极为罕见。本文报告了1例Warthin样黏液表皮样癌、1例Warthin瘤合并黏液表皮样癌、1例Warthin瘤伴黏液化生，并讨论了Warthin瘤与黏液表皮样癌之间的可能联系。.

OBJECTIVE: Primary mucoepidermoid carcinomas (MECs) of the sinonasal tract and nasopharynx are rare entities that represent a diagnostic challenge, especially in biopsy samples. Herein, we present a case series of MECs of the sinonasal and skull base and its mimics to evaluate the clinicopathological and molecular characteristics in order to avoid misdiagnosis.
METHODS: We reviewed the pathology records of patients diagnosed from 2014 to 2022. Thirty MECs were consecutively diagnosed during that period.
RESULTS: Based on morphological and fluorescence in situ hybridization (FISH) analyses, 30 tumors originally diagnosed as MECs were separated into MAML2 fusion-positive (7 cases) and MAML2 fusion-negative groups (23 cases), in which 14 tumors were positive for the EWSR1::ATF1 fusion; these tumors were reclassified to have hyalinizing clear cell carcinoma (HCCC). The remaining nine MAML2 FISH negative cases were reconfirmed as squamous cell carcinoma (SCC, 3 cases) which showed keratinization and high Ki-67 expression; DEK::AFF2 carcinomas (2 cases), in which DEK gene rearrangement was detected by FISH; and MECs as previously described (4 cases) with typical morphological features. Including 7 MAML2 rearrangements tumors, 11 MEC cases had a male-to-female ratio of 4.5:1, and 6 tumors arose from the nasopharyngeal region, while 5 tumors arose from the sinonasal region. The prognosis of this series of salivary gland-type MECs was favorable.
CONCLUSIONS: Our study confirmed that HCCC runs the risk of being misdiagnosed as MEC in the sinonasal tract and nasopharynx, particularly with biopsy specimens. Careful histological evaluation with supporting molecular testing can facilitate pathological diagnoses.

Mammary mucoepidermoid carcinoma (MEC) is a rare entity. The molecular characteristics of breast MEC have not been fully investigated due to its rarity. We performed a retrospective study among 1000 patients with breast carcinomas and identified four cases of breast MEC. Clinical and demographic data were collected. Immunohistochemistry panels which were used to diagnose salivary gland MEC and breast carcinomas were also performed. MAML2 rearrangements were detected by FISH and fusion partners were identified by RNA sequencing. Whole-exome sequencing (WES) was used to reveal the genomes of these four breast MEC. Then, the biological functions and features of breast MEC were further compared with those of invasive breast carcinomas and salivary gland MEC.According to Ellis and Auclair\'s methods, these four breast MEC could be classified as low-grade breast MEC. All the patients were alive, and disease-free survival (PFS) ranged from 20 months to 67 months. Among these four breast MEC, two cases were triple-negative, and the other two cases were found to be ER positive, with one also showing HER2 equivocal by immunohistochemical staining, but no amplification in FISH. FISH analysis confirmed the presence of the MAML2 translocation in three of four tumors, and CRTC1-MAML2 fusion was confirmed in two of them by RNA-sequencing. The average coverage size of WES for the tumor mutation burden estimation was 32 Mb. MUC4, RP1L1 and QRICH2 mutations were identified in at least three tumors, and these mutation also existed in breast invasive carcinoma databases (TCGA, Cell 2015; TCGA, Nature 2012). The results showed that there were many genes in breast MEC overlapping with the breast invasive carcinoma databases mentioned above, range from 5 to 63 genes (median:21 genes). Next, we assessed immune cell infiltration levels in these tumors. In all these tumors, M2 macrophages and plasma cell were in the high infiltration group. Our breast MEC showed different results from the salivary gland MEC, whose plasma cells were in the low infiltration group. Overall, we first analyzed the genomics and tumor microenvironment of breast mucoepidermoid carcinoma and proposed our hypothesis that although MECs arising in the breast resemble their salivary gland counterparts phenotypically, our findings indicate that breast MECs probably resemble invasive breast carcinomas at the genetic level and immune cell infiltration levels. More cases and in deep research need to be done to further understand this rare carcinoma.