RET Alterations Differentiate Molecular Profile of Medullary Thyroid Cancer.

PURPOSE: Medullary thyroid cancer (MTC) is a rare cancer originating from parafollicular C cells of the thyroid gland. Therapeutically relevant alterations in MTC are predominantly reported in RET oncogene, and lower-frequency alterations are reported in KRAS and BRAF. Nevertheless, there is an unmet need existing to analyze the MTC in the Indian cohort by using in-depth sequencing techniques that go beyond the identification of known therapeutic biomarkers. MATERIALS AND METHODS: Here, we characterize MTC using integrative whole-exome and whole-transcriptome sequencing of 32 MTC tissue samples. We performed clinically relevant variant analysis, molecular pathway analysis, tumor immune-microenvironment analysis, and structural characterization of RET novel mutation. RESULTS: Mutational landscape analysis shows expected RET mutations in 50% of the cases. Furthermore, we observed mutations in known cancer genes like KRAS, HRAS, SF3B1, and BRAF to be altered only in the RET-negative cohort. Pathway analysis showed differential enrichment of mutations in transcriptional deregulation genes in the RET-negative cohort. Furthermore, we observed novel RET kinase domain mutation Y900S showing affinity to RET inhibitors accessed via molecular docking and molecular dynamics simulation. CONCLUSION: Altogether, this study provides a detailed genomic characterization of patients with MTC of Indian origin, highlighting the possible utility of targeted therapies in this disease.

Primary Pancreatic GIST - A-Single Centre Case Series and Systematic Review of Literature.

PURPOSE: GISTs arising from organs outside GI tract are defined as extragastrointestinal GISTs (EGIST). The majority of EGISTs arise from small intestinal mesentry, mesocolon, omentum, retroperitoneum, abdominal wall, liver and pancreas with pancreas comprising less than 5% of it. Due to limited data, it is unknown if the results of GIST can be generalised for EGISTs. We thereby present the largest single-centre case series of primary pancreatic GIST so far with review of existing literature. METHODS: A total of 9 patients of primary pancreatic GIST were treated at our institute from September 2016 to February 2023. After literature search for all studies published before February 2023, 51 articles including 57 patients were identified. Their clinicopathological data and survival analysis were assessed. RESULTS: The median age of patients treated at our centre was 53 years with a female predominance. The most common epicentre was pancreatic head with abdominal pain as the most common presenting symptom. All 57 patients documented in literature belonged to a similar age group with similar gender predilection. The factors impacting DFS were histologic type, mitotic index, NIH risk category and adjuvant therapy. The median DFS was 74 months with a 5-year DFS being 71.9%, while the 5-year OS was 90.4%. CONCLUSION: Pancreatic GIST is a rare entity. Due to limited evidence and evolving literature, results cannot be generalised to a larger population. Larger case series with longer follow-up data are required to further understand the disease biology and long-term outcomes of pancreatic GIST.

Advancements in diagnosing IgG4-related disease of the head and neck: Navigating diagnostic pitfalls.

IgG4-related disease (IgG4-RD) is an immune-mediated condition affecting nearly any organ. This review focuses on the nuances of diagnosing IgG4-RD affecting the head and neck. Salivary gland involvement, especially of the submandibular glands, often permits a definitive diagnosis on biopsy. However, elevated IgG4+ plasma cells are nonspecific and can be seen in chronic sialadenitis, lymphoma, and other mimics. Careful correlation of clinical and pathological findings is essential. Given the significant overlap with chronic sinusitis, IgG4-RD of the sinonasal region is difficult to diagnose histologically. Laryngeal and pharyngeal involvement appears rare as an isolated finding of IgG4-RD. Mastoid disease is uncommon and remains a diagnosis of exclusion. Thyroid manifestations pose challenges given unclear diagnostic criteria - Riedel's thyroiditis likely represents IgG4-RD, but the fibrosing variant of Hashimoto's thyroiditis as a form of the so-called 'IgG4-related thyroiditis' requires better characterisation. Eosinophilic angiocentric fibrosis, despite histologic similarities, only partially overlaps with IgG4-RD. This review aims to guide diagnosing IgG4-RD in the head and neck through a systematic, organ-focused discussion of the clinical context, the utility of immunostaining, histological mimics, and controversial issues that pose diagnostic pitfalls. Increased awareness of the nuances and difficulties diagnosing IgG4-RD affecting the head and neck will improve recognition of this protean disease.

NIPBL::NACC1 Fusion Hepatic Carcinoma.

Several reports describing a rare primary liver tumor with histologic features reminiscent of follicular thyroid neoplasms have been published under a variety of descriptive terms including thyroid-like, solid tubulocystic, and cholangioblastic cholangiocarcinoma. Although these tumors are considered to represent histologic variants, they lack classic features of cholangiocarcinoma and have unique characteristics, namely immunoreactivity for inhibin and NIPBL::NACC1 fusions. The purpose of this study is to present clinicopathologic and molecular data for a large series of these tumors to better understand their pathogenesis. We identified 11 hepatic tumors with these features. Immunohistochemical and NACC1 and NIPBL fluorescence in situ hybridization assays were performed on all cases. Four cases had available material for whole-genome sequencing (WGS) analysis. Most patients were adult women (mean age: 42 y) who presented with abdominal pain and large hepatic masses (mean size: 14 cm). Ten patients had no known liver disease. Of the patients with follow-up information, 3/9 (33%) pursued aggressive behavior. All tumors were composed of bland cuboidal cells with follicular and solid/trabecular growth patterns in various combinations, were immunoreactive for inhibin, showed albumin mRNA by in situ hybridization, and harbored the NIPBL::NACC1 fusion by fluorescence in situ hybridization. WGS corroborated the presence of the fusion in all 4 tested cases, high tumor mutational burden in 2 cases, and over 30 structural variants per case in 3 sequenced tumors. The cases lacked mutations typical of conventional intrahepatic cholangiocarcinoma. In this report, we describe the largest series of primary inhibin-positive hepatic neoplasms harboring a NIPBL::NACC1 fusion and the first WGS analysis of these tumors. We propose to name this neoplasm NIPBL:NACC1 fusion hepatic carcinoma.

Evaluation of an Objective MRI-Based Tumor Regression Grade (mrTRG) Score and a Subjective Likert Score for Assessing Treatment Response in Locally Advanced Rectal Cancers-A Retrospective Study.

Purpose: Magnetic resonance imaging (MRI) with the help of MRI-based tumor regression grade (mrTRG) score has been used as a tool to predict pathological tumor regression grade (pTRG) in patients of rectal cancer post-neoadjuvant chemoradiation. Our study aims to evaluate the ability of MRI in assessing treatment response comparing an objective mrTRG score and a subjective Likert score, with a focus on the ability to predict pathologic complete response (pCR). Methods: Post-treatment MRI studies were retrospectively reviewed for 170 consecutive cases of histopathologically proven rectal cancer after receiving neoadjuvant chemoradiation and prior to surgery by two oncoradiologists blinded to the eventual postoperative histopathology findings. An objective (mrTRG) and a subjective Likert score were assigned to all the cases. Receiver operating characteristic curves were constructed to determine the ability of Likert scale and mrTRG to predict pCR, with postoperative histopathology being the gold standard. The optimal cutoff points on the scale of 1 to 5 were obtained for mrTRG and Likert scale with the greatest sum of sensitivity and specificity using the Youden Index. Results: The most accurate cutoff point for the mrTRG to predict complete response was 2.5 (using Youden index), with a sensitivity of 69.2%, specificity of 69.6%, positive predictive value (PPV) of 85.6%, negative predictive value (NPV) of 46.4%, and accuracy of 69.3%. The most accurate cutoff for the Likert scale to predict complete response was 3.5, with a sensitivity of 47.5%, specificity of 89.1%, PPV of 91.9%, NPV of 39.4%, and accuracy of 59%. mrTRG had a lower cutoff and was more accurate in predicting pCR compared to Likert score. Conclusion: An objective mrTRG was more accurate than a subjective Likert scale to predict complete response in our study.

Role of imaging in the management of thyroglossal duct cyst carcinomas (TGC-TIRADS): a single centre retrospective study over 16 years.

Introduction: Thyroglossal duct cyst (TGDC) is the most frequently encountered developmental anomaly in thyroid genesis with a reported incidence of 7% in the adult population. The cyst is known to develop anywhere along the pathway of thyroid descent but is more frequently seen in the infrahyoid neck in the midline. The incidence of malignancy in a TGDC is approximately 1%; a majority of these are papillary carcinomas. This study was conducted at a single tertiary care centre which spanned over a decade which adds practice changing evidence-based knowledge to existing literature on this rare entity. A comprehensive study which conclusively establishes the imaging features predictive of malignancy in TGDC carcinomas (TGDCa), the protocol for optimal management, clinical outcome and long-term survival of these patients is not available. Although TGDC carcinoma is thought to have an excellent prognosis, there is not enough data available on the long-term survival of these patients. The aim of this study was to identify whether neck ultrasound (US) can serve as an accurate imaging tool for the preoperative diagnosis of TGDC carcinomas. Methods: We accessed the electronic medical records of 86 patients with TGDC between January 2005 to December 2021. Of these, 22 patients were detected with TGDC papillary carcinoma on histopathologic examination. Relevant imaging, treatment and follow up information for all cases of TGDC carcinoma were retrospectively reviewed. We compared US characteristics predictive of malignancy across outcomes groups; malignant vs benign using the Chi-square test. Based on the results, a TGC-TIRADS classification was proposed with calculation of the percentage likelihood of malignancy for each category. Results: Compared to benign TGDCs, malignant TGDCs were more likely to present with following US characteristics: irregular or lobulated margins (90.40 vs. 38.10%), solid-cystic composition (61.90 vs. 17.07%), internal vascularity (47.62 vs. 4.88 %), internal calcification (76.19 vs. 7.32 %) (each p value < 0.005). Calcifications and internal vascularity were the most specific while irregular/lobulated margins were the most sensitive feature for malignancy. AUC under the ROC curve was 0.88. Allpatients were operated and were disease free at the end of 5 years or till the recent follow up. Discussion: US is the imaging modality of choice for pre-operative diagnosis of TGDC carcinoma. Thepre-operative diagnosis and risk stratification of thyroglossal lesions will be aided by the application of the proposed TGC-TIRADS classification, for which the percentage likelihood of malignancy correlated well with the results in our study. Sistrunk procedure is adequate for isolated TGDC carcinoma; suspicious neck nodes on imaging also necessitates selective nodal dissection. Papillary carcinomas have an excellent prognosis with low incidence of disease recurrence.

Role of computed tomography in the evaluation of regional metastasis in well-differentiated thyroid cancer.

Background: Accurate neck staging is essential for performing appropriate surgery and avoiding undue morbidity in thyroid cancer. The modality of choice for evaluation is ultrasonography (US), which has limitations, particularly in the central compartment, that can be overcome by adding a computed tomography (CT). Methods: A total of 314 nodal levels were analyzed in 43 patients with CT, and US; evaluations were done between January 2013 and November 2015. The images were reviewed by two radiologists independently who were blinded to histopathological outcomes. The sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV), and accuracy of US, CT, and US + CT were calculated using histology as the gold standard. Results: The overall sensitivity, specificity, PPV, and NPV for US, CT, and US + CT were 53.9%, 88.8%, 74.1%, and 76.4%; 81.2%, 68.0%, 60.1%, and 85.9%; and 84.6%, 66.0%, 59.6%, and 87.8%, respectively. The overall accuracy of the US was 75.80%, the CT scan was 72.93%, and the US + CT scan was 72.93%. For the lateral compartment, the sensitivity, specificity, PPV, and NPV for the US, CT, and US + CT were 56.6%, 91.4%, 77.1%, and 80.5%; 80.7%, 70.6%, 58.3%, and 87.8%; and 84.3%, 68.7%, 57.9%, and 89.6%, respectively. The accuracy of the US was 79.67%, the CT scan was 73.98%, and the US + CT scan was 73.98% for the lateral compartment. For the central compartment, the sensitivity, specificity, PPV, and NPV for the US, CT, and US + CT were 47.1%, 76.5%, 66.7%, and 59.1%; 82.4%, 55.9%, 65.1%, and 76.0%; and 85.3%, 52.9%, 64.4%, and 78.3%, respectively. The accuracy of the US was 61.76%, the CT scan was 69.12%, and the US + CT scan was 69.12% for the central compartment. Conclusions: This study demonstrated that CT has higher sensitivity in detecting nodal metastasis; however, its role is complementary to US due to low specificity.

Association of Cutibacterium acnes with human thyroid cancer.

Introduction: The diverse subtypes of thyroid carcinoma have distinct clinical outcomes despite a comparable spectrum of underlying genetic alterations. Beyond genetic alterations, sparse efforts have been made to characterize the microbes associated with thyroid cancer. In this study, we examine the microbial profile of thyroid cancer. Methods: We sequenced the whole transcriptome of 70 thyroid cancers (40 papillary and 30 anaplastic). Using Infectious Pathogen Detector IPD 2.0, we analysed the relative abundance of 1060 microbes across 70 tumours from patients with thyroid cancer against 118 tumour samples from patients with breast, cervical, colorectal, and tongue cancer. Results: Our analysis reveals a significant prevalence of Cutibacterium acnes in 58.6% thyroid cancer samples compared to other cancer types (p=0.00038). Immune cell fraction analysis between thyroid cancer samples with high and low Cutibacterium loads identify enrichment of immunosuppressive cells, including Tregs (p=0.015), and other anti-inflammatory cytokines in the tumour microenvironment, suggesting an immune evasion/immunosuppression milieu is associated with the infection. A higher burden of Cutibacterium acnes was also found to be associated with poor survival defining a distinct sub-group of thyroid cancer. Conclusion: Cutibacterium acnes is associated with immune suppression and poor prognosis in a subpopulation of thyroid cancer. This study may help design novel therapeutic measures involving appropriate antibiotics to manage the disease better.

Response assessment of post-treatment head and neck cancers to determine further management using NI-RADS (Neck Imaging Reporting and Data System): a subgroup analysis of a randomized controlled trial.

Objective: Interpreting complex post-treatment changes in head and neck cancer (HNC) is challenging with further added perplexity due to variable interobserver interpretation and hence evolved the NI-RADS lexicon. We evaluated the accuracy of NI-RADS in predicting disease status on 1st post-treatment follow-up CECT in a homogenous cohort of those who received only chemoradiation. Methods: Retrospective analysis of imaging was done for LASHNC patients who received radical chemoradiation in an open-label, investigator-initiated, phase 3 randomized trial (2012-2018) randomly assigned to either radical radiotherapy with concurrent weekly cisplatin (CRT) or CRT with the same schedule plus weekly nimotuzumab (NCRT). 536 patients were accrued, and 74 patients who did not undergo PET/CECT after 8 weeks post-CRT were excluded. After assessing 462 patients for eligibility to allocate NI-RADS at primary and node sites, 435 cases fell in the Primary disease cohort and 412 cases in the Node disease cohort. We evaluated sensitivity, disease prevalence, the positive and negative predictive value of the NI-RADS lexicon, and accuracy, which were expressed as percentages. We also prepared flow charts to determine concordance with allocated NI-RADS category and established accuracy with which it can identify disease status. Results: Out of 435 primary disease cohort, 92%, 55%, 48%,70% were concordant and had 100%, 72%, 70%, 82% accuracy in NI-RADS1 (n=12), NI-RADS2 (n=261), NIRADS3 (n=105), and NI-RADS 4 (n=60) respectively. Out of 412 nodes disease cohort, 95%, 90%, 48%, 70%were concordant and had 92%, 97%, 90%, 67% accuracy in NI-RADS1 (n=57), NI-RADS2 (n=255), NI-RADS3 (n=105) and NI-RADS4 (n=60) respectively. % concordance of PET/CT and CECT across all primary and node disease cohorts revealed that PET/CT was 91% concordant in primary NI-RADS2 as compared to 55% concordance of CECT whereas concordance of CECT was better with 57% in primary NI-RADS3 cohort as compared to PET/CT concordance of 41%. Conclusion: The accuracy with which the NI-RADS lexicon performed in our study at node sites was better than that at the primary site. There is a great scope of research to understand if CECT performs better over clinical disease status in NI-RADS 3 and 4 categories. Further research should be carried out to understand if PET/CECT can be used for close interval follow-up in stage III/IV NI-RADS 2 cases.

Prognostic Impact of Poor Differentiation of Squamous Cell Carcinoma in Treatment Naïve Node-Negative Early Oral Cancers.

We have conducted this study to understand the impact of poor differentiation (PD), as a sole poor prognostic factor, in early oral cancers. This was a retrospective analysis of a prospectively maintained database of clinically node-negative early T stage OSCC patients operated between 2012 and 2014. Impact of PD on the survival and role of adjuvant therapy in these patients was noted. Out of 1172 patients screened, 280 patients were found to be eligible for the study. 11.4% patients had PDSCC. It was found to be associated with tongue cancers and peri-neural invasion. It had a significant impact on OS and DFS (48.7 months vs 81.4 months, p < 0.00 and 44.6 months vs 73.5 months, p < 0.00 respectively. Hazard ratio for DFS: 4.08. Although patients with PDSCC had better survival with radiotherapy, but this was not statistically significant. Poor differentiation as a stand-alone factor impacts survival in patients with early oral cancer. It may be seen more often in patients with tongue cancer and may have associated PNI. The role of adjuvant therapy in such patients is not clear.

Rapid on-site evaluation (ROSE) versus macroscopic on-site evaluation (MOSE) for endoscopic ultrasound-guided sampling of solid pancreatic lesions: a paired comparative analysis using newer-generation fine needle biopsy needles.

Background: Rapid on-site examination (ROSE) during endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) has been a subject of debate. We compared the yield of EUS-FNB with adequacy assessed using macroscopic on-site evaluation (MOSE), and smear cytology with adequacy confirmed by ROSE, acquired using the same needle. Methods: Consecutive patients with solid pancreatic lesions (SPLs) who underwent EUS-FNB of pancreatic solid lesions between January 2021 and July 2022 were included. Demographic details, site and size of lesion, number of passes, and the diagnosis by cytology and histopathology of core tissue were noted. The first pass was used for ROSE adequacy assessment and was subsequently sent for cytological assessment. Additional passes were taken subsequently to acquire core tissue. Adequacy was confirmed by MOSE (whitish core of more than 4 mm). Final cytology and histopathology (HPE) were compared for diagnostic accuracy. Results: One hundred fifty-five patients were included in the analysis during the study period (mean age 55.1+12.9 years; 60% male; 77% in pancreatic head; median size 3.7 cm). The final diagnosis was malignancy in 129, while 26 were negative for malignancy. Sensitivity and specificity for ROSE with cytology in detecting malignant SPLs were 96.9% and 100%, respectively. HPE with MOSE had sensitivity and specificity of 96.1% and 100%, respectively. A comparison of diagnostic accuracy showed no significant difference (P>0.99) between HPE with MOSE and ROSE with cytology, using an FNB needle. Conclusion: MOSE is as good as ROSE in terms of diagnostic yield for solid pancreatic lesions sampled using newer-generation EUS biopsy needles.

Top 10 Histological Mimics of Neuroendocrine Carcinoma You Should Not Miss in the Head and Neck.

BACKGROUND: The spectrum of neuroendocrine neoplasia (NEN) of the head and neck region is wide-ranging and diverse, including a variety of diagnoses stretching from benign and low-malignant tumor forms to highly proliferative, poor prognosis neuroendocrine carcinoma (NEC). Moreover, there are several non-neuroendocrine differential diagnoses to keep in mind as well, displaying various degree of morphological and/or immunohistochemical overlap with bona fide neuroendocrine lesions. METHODS: Review. RESULTS: While the growth patterns may vary, well-differentiated NEN usually display a stippled "salt and pepper" chromatin, a granular cytoplasm, and unequivocal expression of neuroendocrine markers such as chromogranin A and synaptophysin. However, these features are often less pronounced in NEC, which may cause diagnostic confusion-not the least since several non-NEC head and neck tumors may exhibit morphological similarities and focal neuroendocrine differentiation. CONCLUSION: As patients with NEC may require specific adjuvant treatment and follow-up, knowledge regarding differential diagnoses and potential pitfalls is therefore clinically relevant. In this review, the top ten morphological and/or immunohistochemical mimics of NEC are detailed in terms of histology, immunohistochemistry, and molecular genetics.

Assessing the Agreement Between Preoperative Fine-Needle Aspiration Cytology (FNAC) Done for Major Salivary Gland Neoplasm When Reported by Head and Neck Pathologists and Non-head and Neck Pathologists with Its Final Histopathology.

The preoperative FNA is an important investigation in the workup of a salivary gland pathology. A preoperative diagnosis is important to plan management and counsel patients accordingly. In this study, we aimed to assess the agreement between the preoperative FNA and the final histopathology report when reported by a head and neck and a non-head and neck pathologist. All patients with major salivary gland neoplasm having undergone a preoperative FNA before surgery from January 2012 to December 2019 at our hospital were included in the study. Analysis was done to check for concordance between head and neck and non-head and neck pathologists of the preoperative FNA and final histopathology. Three hundred and twenty-five patients were included in the study. The preoperative FNA could identify the tumour as benign or malignant in the majority (n = 228, 70.1%). The agreement between the preoperative FNA, frozen section diagnosis and the reporting of grade in the frozen section and the final HPR was slightly better with the head and neck pathologist (kappa = 0.429, kappa = 0.698 and kappa = 0.257), respectively, than with the non-head and neck pathologist (kappa = 0.387, kappa = 0.519 and kappa = 0.158), all of which was statistically significant (p < 0.001). The diagnosis made with the preoperative FNA and reporting in the frozen section had a fair agreement with the final histopathology when reported by a head and neck pathologist in comparison to a non-head and neck pathologist.

Nonsalivary Primary Adenocarcinomas of the Base of the Tongue: A Single Tertiary-Care Oncology Center Series of 6 Cases.

CONTEXT.­: Nonsalivary primary adenocarcinomas of the base of the tongue (PABOTs) are extremely rare and worth reporting. OBJECTIVE.­: To study the detailed clinicopathologic features of PABOT. DESIGN.­: Cases of PABOT diagnosed on pathology material were retrieved from the archived electronic surgical pathology records. RESULTS.­: Six cases in 4 men and 2 women (M:F ratio, 2:1), with an age range of 31 to 76 years, satisfied the criteria. The tumor epicenter was the base of the tongue in all (6 of 6; 100%), with extension to the epiglottis in 50% (3 of 6), nodal metastasis in 66.7% (4 of 6), and distant metastasis in 33.3% (2 of 6). On histology, all but one were pure adenocarcinoma. Five of 6 cases (83.3%) had a gastrointestinal (GI) phenotype, of which 2 (40%) had a colonic/lower-GI-type (small groups of cells floating in mucin, CK20+, SATB2+, and CDX2+) and 3 (60%) had an upper-GI-like adenocarcinoma (UGI-LA; malignant glands with intracellular mucin, CK7+) histology. Cystic structure suggestive of teratomatous origin was identified in 2 of 5 cases (40%), both with UGI-LA phenotype. The non-GI-type case had a unique histology with squamous differentiation in addition to adenocarcinoma areas, diffuse nuclear ß-catenin on immunohistochemistry, and a corresponding exon 3 CTNNB1 mutation. One patient succumbed to disease, and 4 are alive with disease (follow-up of 1-9 months after completion of therapy). CONCLUSIONS.­: We suggest using the broad term primary adenocarcinomas of the base of tongue (PABOTs), which can be further subdivided into colonic-type adenocarcinoma of the tongue and oral cavity, UGI-LA, and not otherwise specified categories, and reiterate a need for recognition and distinction of PABOT from salivary gland tumors. A subset originates from teratoid/duplication cysts, necessitating extensive sampling. Multicentric studies are essential to clinically and biologically prognosticate each of these categories.

Role of miR-944/MMP10/AXL- axis in lymph node metastasis in tongue cancer.

Occult lymph-node metastasis is a crucial predictor of tongue cancer mortality, with an unmet need to understand the underlying mechanism. Our immunohistochemical and real-time PCR analysis of 208 tongue tumors show overexpression of Matrix Metalloproteinase, MMP10, in 86% of node-positive tongue tumors (n = 79; p < 0.00001). Additionally, global profiling for non-coding RNAs associated with node-positive tumors reveals that of the 11 significantly de-regulated miRNAs, miR-944 negatively regulates MMP10 by targeting its 3'-UTR. We demonstrate that proliferation, migration, and invasion of tongue cancer cells are suppressed by MMP10 knockdown or miR-944 overexpression. Further, we show that depletion of MMP10 prevents nodal metastases using an orthotopic tongue cancer mice model. In contrast, overexpression of MMP10 leads to opposite effects upregulating epithelial-mesenchymal-transition, mediated by a tyrosine kinase gene, AXL, to promote nodal and distant metastasis in vivo. Strikingly, AXL expression is essential and sufficient to mediate the functional consequence of MMP10 overexpression. Consistent with our findings, TCGA-HNSC data suggests overexpression of MMP10 or AXL positively correlates with poor survival of the patients. In conclusion, our results establish that the miR-944/MMP10/AXL- axis underlies lymph node metastases with potential therapeutic intervention and prediction of nodal metastases in tongue cancer patients.

A Rare Case of A Low-Grade Inflammatory Leiomyosarcoma/Histiocyte-Rich Rhabdomyoblastic Tumor in the Neck of An Adolescent Male.

Inflammatory leiomyosarcoma (LMS) is a newly included rare tumor entity in the group of smooth muscle tumors in the recent WHO classification. Recent studies have shown skeletal muscle expression within this tumor and its proximity with histiocyte-rich rhabdomyoblastic tumor (HRRT). A 17-year-old male presented with a soft tissue lump over the back of his neck of one-year duration. Radiologically, a lesion measuring 5.9 cm in the largest dimension was seen, extending from the skull base up to the C2 vertebral level, abutting the occipital bone. The initial biopsy was reported as a fibrohistiocytic tumor at the referring laboratory. A microscopic review of the sections from the initial biopsy and subsequent resection revealed a well-circumscribed, cellular tumor composed of plump spindle and polygonal-shaped tumor cells with relatively bland nuclei, moderate to abundant eosinophilic cytoplasm and numerous interspersed histiocytes, including foam cells and lymphocytes. Immunohistochemically, the tumor cells were positive for desmin, MYOD1 and SMA, focally positive for myogenin, while negative for h-caldesmon, SOX10 and S100P. A diagnosis of inflammatory leiomyosarcoma/HRRT was offered. Subsequently, the tumor was tested for MYOD1 (L122R) mutation and was found to be negative. The patient underwent adjuvant radiation therapy and is free-of-disease at 12 months post-treatment. This case constitutes an extremely rare case of an inflammatory LMS/HRRT, identified in the neck region. This tumor should be differentiated from its close mimics, such as a spindle cell/sclerosing rhabdomyosarcoma, as the latter is treated more aggressively, including with chemotherapy, given its relatively poor prognosis.