Metastatic cutaneous squamous cell carcinoma accounts for nearly all squamous cell carcinomas of the parotid gland.

Primary squamous cell carcinoma of the parotid gland (pSCCP) has long been recognized as a separate entity and is included in the WHO classifications of salivary gland tumors. However, it is widely accepted among head and neck pathologists that pSCCP is exceptionally rare. Yet, there are many publications describing series of pSCCP and data from SEER and other cancer register databases indicate erroneously an increasing incidence of pSCCP. Importantly, pSCCP and metastatic (secondary) squamous cell carcinoma to the parotid gland (mSCCP) have nearly identical histological features, and the diagnosis of pSCCP should only be made after the exclusion of mSCCP. Moreover, all of the histological diagnostic criteria proposed to be in favor of pSCCP (such as, for example, dysplasia of ductal epithelium) can be encountered in unequivocal mSCCP, thereby representing secondary growth along preexistent ducts. Squamous cell differentiation has also been reported in rare genetically defined primary parotid carcinomas, either as unequivocal histological squamous features (e.g., NUT carcinoma, mucoepidermoid carcinoma), by immunohistochemistry (e.g., in NUT carcinoma, adamantinoma-like Ewing sarcoma, basal-type salivary duct carcinoma, mucoepidermoid carcinoma), or a combination of both. Another major issue in this context is that the International Classification of Diseases (ICD) coding system does not distinguish between primary or metastatic disease, resulting in a large number of patients with mSCCP being misclassified as pSCCP. Immunohistochemistry and new molecular biomarkers have significantly improved the accuracy of the diagnosis of many salivary gland neoplasms, but until recently there were no biomarkers that can accurately distinguish between mSCCP and pSCCP. However, recent genomic profiling studies have unequivocally demonstrated that almost all SCCP analyzed to date have an ultraviolet light (UV)-induced mutational signature typical of mSCCP of skin origin. Thus, mutational signature analysis can be a very useful tool in determining the cutaneous origin of these tumors. Additional molecular studies may shed new light on this old diagnostic and clinical problem. This review presents a critical view of head and neck experts on this topic.

DeepDOF-SE: affordable deep-learning microscopy platform for slide-free histology.

Histopathology plays a critical role in the diagnosis and surgical management of cancer. However, access to histopathology services, especially frozen section pathology during surgery, is limited in resource-constrained settings because preparing slides from resected tissue is time-consuming, labor-intensive, and requires expensive infrastructure. Here, we report a deep-learning-enabled microscope, named DeepDOF-SE, to rapidly scan intact tissue at cellular resolution without the need for physical sectioning. Three key features jointly make DeepDOF-SE practical. First, tissue specimens are stained directly with inexpensive vital fluorescent dyes and optically sectioned with ultra-violet excitation that localizes fluorescent emission to a thin surface layer. Second, a deep-learning algorithm extends the depth-of-field, allowing rapid acquisition of in-focus images from large areas of tissue even when the tissue surface is highly irregular. Finally, a semi-supervised generative adversarial network virtually stains DeepDOF-SE fluorescence images with hematoxylin-and-eosin appearance, facilitating image interpretation by pathologists without significant additional training. We developed the DeepDOF-SE platform using a data-driven approach and validated its performance by imaging surgical resections of suspected oral tumors. Our results show that DeepDOF-SE provides histological information of diagnostic importance, offering a rapid and affordable slide-free histology platform for intraoperative tumor margin assessment and in low-resource settings.

Poorly differentiated thyroid carcinomas: conceptual controversy and clinical impact.

Poorly differentiated thyroid carcinomas (PDTC) are rare diseases; nevertheless, they account for the majority of deaths from non-anaplastic follicular cell-derived thyroid carcinomas. Establishing the diagnosis and treatment of PDTC is challenging given the low incidence and the lack of standardization of diagnostic criteria. These limitations hamper the ability to compare therapeutic modalities and outcomes between recent and older studies. Recently, the 5th edition of the classification of endocrine tumors has been published, which includes changes in nomenclature and the addition of the disease entity of "differentiated high-grade follicular cell-derived carcinomas". On the other hand, the recently witnessed advances in molecular diagnostics have enriched therapeutic options and improved prognosis for patients. We herein review the various historical variations and evolution in the diagnostic criteria for PDTC. This systematic review attempts to clarify the evolution of the histological and molecular characteristics of this disease, its prognosis, as well as its treatment options.

The genomic and evolutionary landscapes of anaplastic thyroid carcinoma.

Anaplastic thyroid carcinoma is arguably the most lethal human malignancy. It often co-occurs with differentiated thyroid cancers, yet the molecular origins of its aggressivity are unknown. We sequenced tumor DNA from 329 regions of thyroid cancer, including 213 from patients with primary anaplastic thyroid carcinomas. We also whole genome sequenced 9 patients using multi-region sequencing of both differentiated and anaplastic thyroid cancer components. Using these data, we demonstrate thatanaplastic thyroid carcinomas have a higher burden of mutations than other thyroid cancers, with distinct mutational signatures and molecular subtypes. Further, different cancer driver genes are mutated in anaplastic and differentiated thyroid carcinomas, even those arising in a single patient. Finally, we unambiguously demonstrate that anaplastic thyroid carcinomas share a genomic origin with co-occurring differentiated carcinomas and emerge from a common malignant field through acquisition of characteristic clonal driver mutations.

Decreasing utilization for postoperative radiation therapy in locoregionally advanced medullary thyroid cancer.

BACKGROUND: Use of postoperative radiation therapy (PORT) in locoregionally advanced medullary thyroid cancer (MTC) remains controversial. The objective was to evaluate the effect of PORT on locoregional control (LRC) and overall survival (OS). METHODS: Retrospective cohort study of 346 MTC patients separated into PORT and no-PORT cohorts. Relative indications for PORT, as well as changes in patterns of treatment, were recorded. RESULTS: 49/346 (14%) received PORT. PORT was associated with worse OS; adjusted HR = 2.0 (95%CI 1.3-3.3). PORT was not associated with improved LRC, even when adjusting for advanced stage (Stage III p = 0.892; Stage IV p = 0.101). PORT and targeted therapy were not associated with improved OS compared to targeted therapy alone; adjusted HR = 1.2 (95%CI 0.3-4.1). CONCLUSIONS: Use of PORT in MTC has decreased and its indications have become more selective, coinciding with the advent of effective targeted therapies. Overall, PORT was not associated with improved LRC or OS.

Sinonasal NUT carcinoma: A consecutive case series and systematic review.

BACKGROUND: Sinonasal NUT carcinoma is an extremely rare, lethal malignancy with limited literature. METHODS: A case series was conduction of all patients with sinonasal NUT carcinoma at a single institution between 2010 and 2022. Survival and associated were evaluated. A systematic review of the literature was performed. RESULTS: In 12 patients, followed for a median of 1.5 years, the median overall survival (OS) and disease-specific survival (DSS) were both 14.6 months. Patients with maxillary sinus tumors were 91% more likely to survive (hazard ratio [HR]: 0.094, 95% confidence interval [CI]: 0.011-0.78, p = 0.011). Patients with higher-stage disease stage had worse OS (stage IVb-c vs. III-IVa, p = 0.05). All three patients who were alive with no evidence of disease received induction chemotherapy. CONCLUSION: For patients with sinonasal NUT carcinoma, the median survival was 15 months but better with lower-stage and maxillary tumors. Induction chemotherapy may be beneficial.

Diagnosis and Management of Tropomyosin Receptor Kinase Fusion-Positive Thyroid Carcinomas: A Review.

Importance: Thyroid epithelial malignant neoplasms include differentiated thyroid carcinomas (papillary, follicular, and oncocytic), follicular-derived high-grade thyroid carcinomas, and anaplastic and medullary thyroid carcinomas, with additional rarer subtypes. The discovery of neurotrophic tyrosine receptor kinase (NTRK) gene fusions has fostered developments in precision oncology, with the approval of tropomyosin receptor kinase inhibitors (larotrectinib and entrectinib) for patients with solid tumors, including advanced thyroid carcinomas, harboring NTRK gene fusions. Observations: The relative rarity and diagnostic complexity of NTRK gene fusion events in thyroid carcinoma present several challenges for clinicians, including variable access to robust methodologies for comprehensive NTRK fusion testing and poorly defined algorithms of when to test for such molecular alterations. To address these issues in thyroid carcinoma, 3 consensus meetings of expert oncologists and pathologists were convened to discuss diagnostic challenges and propose a rational diagnostic algorithm. Per the proposed diagnostic algorithm, NTRK gene fusion testing should be considered as part of the initial workup for patients with unresectable, advanced, or high-risk disease as well as following the development of radioiodine-refractory or metastatic disease; testing by DNA or RNA next-generation sequencing is recommended. Detecting the presence of NTRK gene fusions is important to identify patients eligible to receive tropomyosin receptor kinase inhibitor therapy. Conclusions and Relevance: This review provides practical guidance for optimal integration of gene fusion testing, including NTRK gene fusion testing, to inform the clinical management in patients with thyroid carcinoma.

Anaplastic transformation in thyroid cancer revealed by single-cell transcriptomics.

The deadliest anaplastic thyroid cancer (ATC) often transforms from indolent differentiated thyroid cancer (DTC); however, the complex intratumor transformation process is poorly understood. We investigated an anaplastic transformation model by dissecting both cell lineage and cell fate transitions using single-cell transcriptomic and genetic alteration data from patients with different subtypes of thyroid cancer. The resulting spectrum of ATC transformation included stress-responsive DTC cells, inflammatory ATC cells (iATCs), and mitotic-defective ATC cells and extended all the way to mesenchymal ATC cells (mATCs). Furthermore, our analysis identified 2 important milestones: (a) a diploid stage, in which iATC cells were diploids with inflammatory phenotypes and (b) an aneuploid stage, in which mATCs gained aneuploid genomes and mesenchymal phenotypes, producing excessive amounts of collagen and collagen-interacting receptors. In parallel, cancer-associated fibroblasts showed strong interactions among mesenchymal cell types, macrophages shifted from M1 to M2 states, and T cells reprogrammed from cytotoxic to exhausted states, highlighting new therapeutic opportunities for the treatment of ATC.

Impact of Clinical Factors and Treatments on SMARCB1 (INI-1)-Deficient Sinonasal Carcinoma.

The objective of this study was to report outcomes for 19 consecutive patients with SMARCB1 (INI-1)-deficient sinonasal carcinoma. Patients were treated from 2014 to 2021 and followed for a median of 22.3 months. The median overall survival (OS) and disease-free survival (DFS) were 31.8 and 9.9 months, respectively. Patients with nasal cavity or maxillary sinus tumors had 84% better disease-specific survival (DSS) (hazard ratio [HR], 0.136; 95% confidence interval [CI], 0.028-0.66; p = .005) and 71% better DFS (HR, 0.29; 95% CI, 0.097-0.84; p = .041) than patients with other sinonasal sites. Patients who received induction chemotherapy were 76% less likely to die of disease (DSS HR, 0.241; 95% CI, 0.058-1.00; p = .047). In the largest single-institution study of SMARCB1-deficient sinonasal carcinoma to date, OS and DFS approached 3 years and 1 year, respectively, but were better for nasal cavity and maxillary sinus tumors. Patients may benefit from induction chemotherapy.

Surgery After BRAF-Directed Therapy Is Associated with Improved Survival in BRAFV600E Mutant Anaplastic Thyroid Cancer: A Single-Center Retrospective Cohort Study.

Background: The aim of this study was to describe the oncologic outcomes of patients with BRAFV600E-mutated anaplastic thyroid cancer (ATC) who had neoadjuvant BRAF-directed therapy with subsequent surgery. For context, we also reviewed patients who received BRAF-directed therapy after surgery, and those who did not have surgery after BRAF-directed therapy. Methods: This was a single-center retrospective cohort study conducted at a tertiary care cancer center in Texas from 2017 to 2021. Fifty-seven consecutive patients with BRAFV600E-mutated ATC and at least 1 month of BRAF-directed therapy were included. Primary outcomes were overall survival (OS) and progression-free survival (PFS). Results: All patients had stage IVB (35%) or IVC (65%) ATC. Approximately 70% of patients treated with BRAF-directed therapy ultimately had surgical resection of residual disease. Patients who had neoadjuvant BRAF-directed therapy followed by surgery (n = 32) had 12-month OS of 93.6% [confidence interval (CI) 84.9-100] and PFS of 84.4% [CI 71.8-96.7]. Patients who had surgery before BRAF-directed therapy (n = 12) had 12-month OS of 74.1% [CI 48.7-99.5] and PFS of 50% [CI 21.7-78.3]. Finally, patients who did not receive surgery after BRAF-directed therapy (n = 13) had 12-month OS of 38.5% [CI 12.1-64.9] and PFS of 15.4% [CI 0-35.0]. Neoadjuvant BRAF-directed therapy reduced tumor size, extent of surgery, and surgical morbidity score. Subgroup analysis suggested that any residual ATC in the surgical specimen was associated with significantly worse 12-month OS and PFS (OS = 83.3% [CI 62.6-100], PFS = 61.5% [CI 35.1-88]) compared with patients with pathologic ATC complete response (OS = 100%, PFS = 100%). Conclusions: We observed that neoadjuvant BRAF-directed therapy reduced extent of surgery and surgical morbidity. While acknowledging potential selection bias, the 12-month OS rate appeared higher in patients who had BRAF-directed therapy followed by surgery as compared with BRAF-directed therapy without surgery; yet, it was not significantly different from surgery followed by BRAF-directed therapy. PFS appeared higher in patients treated with neoadjuvant BRAF-directed therapy relative to patients in the other groups. These promising results of neoadjuvant BRAF-directed therapy followed by surgery for BRAF-mutated ATC should be confirmed in prospective clinical trials.

Prior Thyroid and Nonthyroid Cancer History Do Not Significantly Alter Overall Survival in Patients Diagnosed with Anaplastic Thyroid Cancer.

Background: A history of thyroid and nonthyroid malignancies has traditionally been an exclusion criterion in patients with anaplastic thyroid cancer (ATC) seeking to enroll in clinical trials. In this study, we examined the impact of prior malignancies on overall survival (OS) in patients diagnosed with ATC. Methods: In our retrospective cohort study, we identified 451 patients with ATC treated at MD Anderson between 2000 and 2019. Clinical and pathological information was obtained through chart review. Survival analyses were conducted using the Kaplan-Meier method and multivariable Cox proportional hazard models. Results: A history of clinically documented differentiated thyroid cancer (DTC) was reported in 14% of patients with ATC (n = 62), most commonly papillary thyroid cancer (81%, n = 50). The median time from diagnosis of prior DTC to ATC diagnosis was 3.5 years (range: 6 months to 35 years). Concomitant DTC was found on pathology in a higher proportion of patients (52%, n = 234). A history of nonthyroid cancer was reported in 23% of patients (n = 102), where 19% (n = 87) had one, 2% (n = 10) had two, and 1% (n = 5) had three prior cancers. The median time from diagnosis of prior nonthyroid cancer to ATC diagnosis was 8 years (range: 3 months to 53 years). The most common prior nonthyroid cancers were nonmelanoma skin (28.4%), prostate (19.6%), and breast cancers (16.7%). In a subgroup analysis performed in patients with available tumor mutation information (n = 183), the frequency of detected tumor driver mutations (BRAF, RAS, TP53) was not significantly different between patients with ATC with and without a history of nonthyroid cancer. On multivariate analysis after adjusting for age and overall stage, prior DTC, concomitant DTC, and prior nonthyroid cancers, all had no significant impact on OS. Conclusions: The presence of prior malignancy does not significantly impact OS in patients with ATC. Revision of eligibility criteria for enrollment of patients with ATC into clinical trials is warranted.

Neoadjuvant checkpoint inhibitor immunotherapy for resectable mucosal melanoma.

Background: Neoadjuvant checkpoint inhibition (CPI) has recently demonstrated impressive outcomes in patients with stage 3 cutaneous melanoma. However, the safety, efficacy, and outcome of neoadjuvant CPI in patients with mucosal melanoma (MM) are not well studied as MM is a rare melanoma subtype. CPI such as combination nivolumab and ipilimumab achieves response rates of 37-43% in unresectable or metastatic MM but there is limited data regarding the efficacy of these agents in the preoperative setting. We hypothesize that neoadjuvant CPI is a safe and feasible approach for patients with resectable MM. Method: Under an institutionally approved protocol, we identified adult MM patients with resectable disease who received neoadjuvant anti-PD1 +/- anti-CTLA4 between 2015 to 2019 at our institution. Clinical information include age, gender, presence of nodal involvement or satellitosis, functional status, pre-treatment LDH, tumor mutation status, and treatment data was collected. Outcomes include event free survival (EFS), overall survival (OS), objective response rate (ORR), pathologic response rate (PRR), and grade ≥3 toxicities. Results: We identified 36 patients. Median age was 62; 58% were female. Seventy-eight percent of patients received anti-PD1 + anti-CTLA4. Node positive disease or satellite lesions was present at the time of treatment initiation in 47% of patients. Primary sites of disease were anorectal (53%), urogenital (25%), head and neck (17%), and esophageal (6%). A minority of patients did not undergo surgery due to complete response (n=3, 8%) and disease progression (n=6, 17%), respectively. With a median follow up of 37.9 months, the median EFS was 9.2 months with 3-year EFS rate of 29%. Median OS had not been reached and 3-year OS rate was 55%. ORR was 47% and PRR was 35%. EFS was significantly higher for patients with objective response and for patients with pathologic response. OS was significantly higher for patients with pathologic response. Grade 3 toxicities were reported in 39% of patients. Conclusion: Neoadjuvant CPI for resectable MM is a feasible approach with signs of efficacy and an acceptable safety profile. As there is currently no standard approach for resectable MM, this study supports further investigations using neoadjuvant therapy for these patients.

Mildly dysplastic oral lesions with optically-detectable abnormalities share genetic similarities with severely dysplastic lesions.

OBJECTIVE: Optical imaging studies of oral premalignant lesions have shown that optical markers, including loss of autofluorescence and altered morphology of epithelial cell nuclei, are predictive of high-grade pathology. While these optical markers are consistently positive in lesions with moderate/severe dysplasia or cancer, they are positive only in a subset of lesions with mild dysplasia. This study compared the gene expression profiles of lesions with mild dysplasia (stratified by optical marker status) to lesions with severe dysplasia and without dysplasia. MATERIALS AND METHODS: Forty oral lesions imaged in patients undergoing oral surgery were analyzed: nine without dysplasia, nine with severe dysplasia, and 22 with mild dysplasia. Samples were submitted for high throughput gene expression analysis. RESULTS: The analysis revealed 116 genes differentially expressed among sites without dysplasia and sites with severe dysplasia; 50 were correlated with an optical marker quantifying altered nuclear morphology. Ten of 11 sites with mild dysplasia and positive optical markers (91%) had gene expression similar to sites with severe dysplasia. Nine of 11 sites with mild dysplasia and negative optical markers (82%) had similar gene expression as sites without dysplasia. CONCLUSION: This study suggests that optical imaging may help identify patients with mild dysplasia who require more intensive clinical follow-up. If validated, this would represent a significant advance in patient care for patients with oral premalignant lesions.

Effectiveness of core needle biopsy in the diagnosis of thyroid lymphoma and anaplastic thyroid carcinoma: A systematic review and meta-analysis.

Background: Both anaplastic thyroid carcinoma (ATC) and thyroid lymphoma (TL) clinically present as rapidly enlarging neck masses. Unfortunately, in this situation, like in any other thyroid swelling, a routine fine-needle aspiration (FNA) cytology is the first and only diagnostic test performed at the initial contact in the average thyroid practice. FNA, however, has a low sensitivity in diagnosing ATC and TL, and by the time the often "inconclusive" result is known, precious time has evolved, before going for core-needle biopsy (CNB) or incisional biopsy (IB) as the natural next diagnostic steps. Objectives: To determine the diagnostic value of CNB in the clinical setting of a rapidly enlarging thyroid mass, via a systematic review and meta-analysis of the available data on CNB reliability in the differential diagnosis of ATC and TL. Methods: A PubMed, Embase and Web of Science database search was performed on June 23th 2021. Population of interest comprised patients who underwent CNB for clinical or ultrasonographical suspicion of ATC or TL, patients with a final diagnosis of ATC or TL after CNB, or after IB following CNB. Results: From a total of 17 studies, 166 patients were included. One hundred and thirty-six were diagnosed as TL and 14 as ATC following CNB. CNB, with a sensitivity and positive predictive value of 94,3% and 100% for TL and 80,1% and 100% for ATC respectively, proved to be superior to FNA (reported sensitivity for TL of 48% and for ATC of 61%). Furthermore, the need for additional diagnostic surgery after CNB was only 6.2% for TL and 17.6% for ATC. Conclusions: Immediately performing CNB for a suspected diagnosis of ATC and TL in a rapidly enlarging thyroid mass is more appropriate and straightforward than a stepped diagnostic pathway using FNA first and awaiting the result before doing CNB.

Evaluating new treatments for anaplastic thyroid cancer.

INTRODUCTION: Anaplastic thyroid cancer (ATC) is one of the most lethal diseases known to humans with a median survival of 5 months. The American Thyroid Association (ATA) recently published guidelines for the treatment of this dreadful thyroid malignancy. AREAS COVERED: This review presents the current therapeutic landscape of this challenging disease. We also present the results from trials published over the last five years and summarize currently active clinical trials. EXPERT OPINION: Recent attempts to improve the prognosis of these tumors are moving toward personalized medicine, basing the treatment decision on the specific genetic profile of the individual tumor. The positive results of dabrafenib and trametinib for ATC harboring the BRAF V600E mutation have provided a useful treatment option. For the other genetic profiles, different drugs are available and can be used to individualize the treatment, likely using drug combinations. Combinations of drugs act on different molecular pathways and achieve inhibition at separate areas. With new targeted therapies, average survival has improved considerably and death from local disease progression or airway compromise is less likely with improvement in quality of life. Unfortunately, the results remain poor in terms of survival.

Impact of Somatic Mutations on Survival Outcomes in Patients With Anaplastic Thyroid Carcinoma.

PURPOSE: Anaplastic thyroid carcinoma (ATC) uniformly present with aggressive disease, but the mutational landscape of tumors varies. We aimed to determine whether tumor mutations affect survival outcomes in ATC. MATERIALS AND METHODS: Patients who underwent mutation sequencing using targeted gene panels between 2005 and 2019 at a tertiary referral center were included. Associations between mutation status and survival outcomes were assessed using Cox proportional hazards models. RESULTS: A total of 202 patients were included, where 122 died of ATC (60%). The median follow-up was 31 months (interquartile range, 18-45 months). The most common mutations were in TP53 (59%), BRAF (41%), TERT promoter (37%), and the RAS gene family (22%). Clinicopathologic characteristics and overall survival (OS) significantly correlated with mutations in BRAFV600E and RAS, which were mutually exclusive. The BRAFV600E mutation was associated with the presence of a papillary thyroid carcinoma precursor and significantly better OS (median OS: 24 months). RAS-mutated patients more commonly presented without cervical lymph node involvement but had the worst OS (median OS: 6 months). Tumors that were wild-type for both BRAF and RAS were enriched for NF1 mutations and harbored intermediate prognosis (median OS: 15 months). In multivariate analyses, RAS mutations were associated with a more than 2.5-fold higher risk of death (adjusted hazard ratio, 2.64; 95% CI, 1.66 to 4.20) compared with BRAFV600E. In patients treated with BRAF-directed therapy (n = 60), disease progression occurred in 48% of patients (n = 29). The median progression-free survival was 14 months. The presence of a TP53 mutation was independently associated with reduced progression-free survival in BRAFV600E-mutated patients treated with BRAF-directed therapy (adjusted hazard ratio, 2.89; 95% CI, 1.35 to 6.21). CONCLUSION: Mutation analysis provides prognostic information in ATC and should be incorporated into routine clinical care.

Multifocal recurrence of pleomorphic adenoma of the lacrimal gland.

Purpose: To report two cases of multifocal recurrent pleomorphic adenoma of the lacrimal gland, and to highlight the clinical and magnetic resonance imaging findings. Observations: The authors present two patients with recurrent pleomorphic adenoma of the lacrimal gland. During their previous primary surgical resection at outside institutions, one patient reportedly had a macroscopically complete excision, while the second patient had violation of the pseudocapsule. Both patients had multiple recurrent nodular lesions detected on magnetic resonance imaging with extension beyond the surgical field of the primary resection. Both underwent subsequent lateral orbitotomy with resection of all identifiable nodules and histopathology was consistent with pleomorphic adenoma. In one patient, two nodules were found two months after the surgery, which grew slowly over the last four years. The second patient had no clinical or radiologic sign of recurrence at last follow up, three years after resection of multinodular recurrence. Conclusions and importance: The two cases demonstrate the challenges in the management of multifocal recurrence of lacrimal gland pleomorphic adenoma. The multicentric nature of recurrent lesions in these two cases increase the risk of future recurrence, malignant transformation, and morbidity caused by surgery and radiation. Magnetic resonance imaging is the imaging study of choice, but it may still be inadequate in identifying all the nodules.

Primary Signet Ring Cell/Histiocytoid Carcinoma of the Eyelid: Clinicopathologic Analysis with Evaluation of the E-Cadherin/ß-Catenin Complex and Associated Genetic Alterations.

Signet Ring Cell (SRC)/Histiocytoid carcinoma of the eyelid is a rare neoplasm that shares histological and immunohistochemical similarities with diffuse gastric cancer and breast lobular carcinoma. The CDH1 gene, which encodes the E-cadherin protein, is the best known gene associated with these tumors. The structural and functional integrity of E-cadherin is regulated by interconnecting molecular pathways which might participate in the development of this disease. Hence, we analyzed the protein expression in key genes in E-cadherin-related pathways associated with primary SRC/Histiocytoid carcinoma of the eyelid. SRC/Histiocytoid carcinoma diagnosed in the eyelid/orbit at MD Anderson Cancer Center from 1990 to 2016 were evaluated. Clinicopathologic findings were studied to confirm the primary site of origin. Immunohistochemical studies for the expression of E-cadherin, ß-catenin, c-Myc, Cyclin D1, Src, and p53 were analyzed. Next generation sequencing for the detection of somatic mutations was performed on each tumor with matched normal tissue, examining 50 cancer-related genes. Four primary SRC/Histiocytoid carcinomas of the eyelid were diagnosed in four male patients aged 40-82 years. Immunohistochemically, two tumors with loss of E-cadherin expression had weak ß-catenin and low cytoplasmic staining for Src while the other two cases with intact E-cadherin showed strong ß-catenin expression and high cytoplasmic expression for Src. Cyclin D1 was focally positive in three cases. Somatic mutations in CDH1, PIK3CA, and TP53 genes were detected in two cases. Our results suggest an abnormality in the convergence of E-cadherin/ß-catenin pathways which may promote tumorigenesis by inducing expression of oncogenes such as Cyclin D1 and C-Myc. Mutations in CDH1, PIK3CA, and TP53 genes could induce E-cadherin dysfunction which takes part in the development and progression of this malignancy.