Intracellular Mucin Research Articles

Lung adenocarcinoma metastatic to the ovary: a retrospective clinicopathological analysis of 17 cases and literature review

Lung adenocarcinoma metastatic to the ovary is rarely detected in clinical practice, and only a few cases have been reported. Its clinicopathological features, molecular genetics, and prognosis have not been well characterised. The data of 17 patients diagnosed with this disease between 2013 and 2022 were analysed retrospectively. All patients were non-smokers, with a median age of 46 years (range 30-71 years). Unilateral ovarian involvement was more frequent than bilateral involvement (58.8% vs 41.2%). Lesions presented as solid ovarian or mixed cystic and solid masses, and nearly two-thirds of the tumours (11/17, 64.7%) had a diameter greater than 10 cm. Solid adenocarcinoma was the most common histological subtype (9/17, 52.9%), and three of the cases showed abundant intracellular mucin and signet ring cells. Acinar adenocarcinoma was the second most common type (6/17, 35.3%), usually of moderate to poor differentiation. The remaining two cases were identified as micropapillary adenocarcinoma and mucinous adenocarcinoma. Multinodular growth, necrosis, and lymphovascular invasion were observed in half of the cases, and most of them had a marked stromal response. The most prevalent molecular alteration was ALK-rearranged (8/17, 47.1%), followed by EGFR gene mutations (5/17, 29.4%). A total of 34 cases, comprising 17 from the cohort and 17 from the literature, were included in the survival analysis. Patients with ALK-rearranged genes demonstrated an 80.0% 2-year overall survival rate, whereas those without ALK rearrangement exhibited a lower rate of 33.7%. Although there appears to be a potentially better prognosis for patients with ALK-rearranged genes, further cases and an extended follow-up period are necessary to substantiate this observation.

Neoplastic Progression in Macroscopic Precursor Lesions of the Pancreas.

Macroscopic precursor lesions of the pancreas represent a complex clinical management problem. Molecular characterization of pancreatic cysts has helped to confirm and refine clinical and pathologic classifications of these lesions, inform our understanding of tumorigenesis in the pancreas, and provide opportunities for preoperative diagnosis. To review the pathologic classification of macroscopic cystic lesions of the pancreas: intraductal papillary mucinous neoplasms (IPMNs), mucinous cystic neoplasms (MCNs), intraductal oncocytic papillary neoplasms (IOPNs), and intraductal tubulopapillary neoplasms (ITPNs), and to describe our current state of understanding of their molecular underpinnings, relationship to invasive carcinomas, and implications for diagnosis and prognostication. We assessed the current primary literature and current World Health Organization Classification of Digestive System Tumours. Macroscopic cystic lesions of the pancreas are morphologically and molecularly diverse. IPMNs and MCNs share mucinous cytoplasm with papillae. MCNs are defined by ovarian-type stroma. IOPNs have granular eosinophilic cytoplasm, prominent nucleoli, and complex, arborizing papillae. ITPNs demonstrate complex, back-to-back tubules and anastomosing papillae and lack prominent intracellular mucin. IPMNs and MCNs are characterized by driver mutations in KRAS/GNAS (IPMNs) and KRAS (MCNs), with later driver events in RNF43, CDKN2A, SMAD4, and TP53. In contrast, IOPNs and ITPNs have recurrent rearrangements in PRKACA/PRKACB and MAPK-associated genes, respectively. The recurrent alterations described in cysts provide an opportunity for diagnosis using aspirated cyst fluid. Molecular characterization of IPMNs shows a striking spatial and mutational heterogeneity, challenging traditional models of neoplastic development and creating challenges to interpretation of cyst fluid sequencing results.

Location Has Prognostic Impact on the Outcome of Colorectal Mucinous Adenocarcinomas.

Mucinous (colloid) adenocarcinomas (MAs) are a rare histological subtype of tumors defined by extracellular mucin comprising more than 50% of the tumor. These tumors are on a continuum of mucin-producing malignancies with signet ring cell adenocarcinomas (SRCCs), which instead produce intracellular mucin. Mucin-containing cancers occur primarily in the stomach and colon, where for SRCCs, outcomes are relatively worse in the proximal stomach and the rectum. It is not known if MAs have similar outcomes. In this study, we use the Surveillance, Epidemiology, and End Results (SEER) database to examine the effects of tumor localization, age, sex, and stage on colorectal and gastric cancer outcomes for MAs. For right colon cancers, MAs are more common, particularly in females, and have slightly better or equivalent outcomes across all stages and ages compared to conventional adenocarcinomas, but outcomes are progressively worse compared to conventional adenocarcinomas for left colon and rectal cancers. Unlike SRCCs, MAs have similar outcomes to conventional adenocarcinomas in all stomach locations. Overall, these results suggest that MAs have an intrinsically different tumor biology in the left colon and rectum that promotes pathogenesis. Decoding this phenomenon could lead to more effectively tailored patient treatment regimens.

FRI498 Paraneoplastic Hyperthyroidism In A Patient With B-hCG Secreting Gastric Carcinoma

Abstract Disclosure: F. Perreault: None. M. Tehfe: None. M. Laskine: None. L. Ste-Marie: None. R. Comtois: None. B. Nguyen: None. J. Murphy-Lavallée: None. A. Rakel: None. Introduction: Human chorionic gonadotropin (hCG) has thyrotropic activity, due to a similar structure to TSH. Increased hCG serum levels can cause hyperthyroidism secondary to TSH-receptor activation. hCG can be increased in conditions outside of pregnancy, such as gestational trophoblastic disease and other tumors. Common hCG secreting tumors are non-seminomatous germ cell tumors, including choriocarcinoma and teratoma1. Even if gastric adenocarcinomas can secrete ß-hCG, the serum level is rarely elevated2. Clinical Case: A 75-year-old man presented to the hospital for abdominal pain, diarrhea, and important recent weight loss. The patient was known for hypertension, dyslipidemia, type 2 diabetes, and chronic kidney disease. He had been investigated for sub-clinical hyperthyroidism one year prior (TSH 0.27 mUI/L (N 0.38-5.33), T4 14 pmol/L (N 8.0-20.0), T3 4.7 pmol/L (N 3.8-6.0), normal thyroid ultrasound and normal uptake at scintigraphy). At physical examination, the patient looked anxious, had a light lid lag, sinus tachycardia (120 BPM) and a new systolic heart murmur. The thyroid exam was normal and there was no pretibial myxedema nor exophthalmia. The blood tests showed normocytic anemia (Hb 113 g/L, N>130), low TSH (< 0.01 mUI/L), and elevated free T4 (74.1 pmol/L) and T3 (22.5 pmol/L). A work-up for hyperthyroidism revealed normal anti-TPO (4 UI/mL, N<9) and TSH receptor (1.2 UI/L, N<1.8) antibodies levels. Tc-99m thyroid scintigraphy showed homogeneous and intense uptake, with no nodule. Additionally, the abdominal CT-scan revealed multiple retroperitoneal lymphadenopathies and liver hypodensities, suspicious of neoplasia. In this context, the patient underwent gastroscopy, and a gastric antral mass was discovered. Neoplastic markers were measured and, unexpectedly, ß-hCG was strongly elevated (>1 080 800 U/L, N<2.0). Testicle ultrasound was normal. The antral mass biopsy was consistent with infiltrating gastric adenocarcinoma, with ring cells containing intracellular mucin and expressing hCG. The patient was treated with methimazole and propranolol. Free T3 and T4 initially decreased with this treatment (to 7.1 pmol/L and 46.4 pmol/L respectively), but one month later, the serum values were higher (14.9 pmol/L and 69.2 pmol/L). No follow-up was possible for this patient as he passed away before receiving treatment for cancer. Conclusion: ß-hCG induced hyperthyroidism can aggravate patients’ malignant manifestations and should be considered in cases presenting with concomitant cancer and hyperthyroidism.

CLINICAL PATHOLOGIC CONFERENCE CASE 1: A MULTILOCULAR RADIOLUCENCY OF THE RIGHT MANDIBLE

CLINICAL PATHOLOGIC CONFERENCE CASE 1: A MULTILOCULAR RADIOLUCENCY OF THE RIGHT MANDIBLE

Primary signet ring cell carcinoma of the breast: A case report and literature review

ABSTRACT Primary signet ring cell carcinoma (SRCC) of the breast is a rare and aggressive type of breast cancer characterized by increased intracellular mucin production. It has a high risk of metastasis and poor prognosis compared to other breast cancer types. We report a 56-year-old woman with primary SRCC of the breast who first presented with retraction on her left breast. Radiological examination revealed a mass that causes the retraction. The patient underwent left modified radical mastectomy, and pathology results showed a 70% signet ring cell pattern. Chemotherapy consists of an adriamycin-cyclophosphamide regimen administered. in this case, we aim to review the literature on this topic and inform the physicians.

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

Nonsalivary primary adenocarcinomas of the base of the tongue (PABOTs) are extremely rare and worth reporting. To study the detailed clinicopathologic features of PABOT. Cases of PABOT diagnosed on pathology material were retrieved from the archived electronic surgical pathology records. 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 β-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). 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.

Clinicopathological features of colorectal amphicrine carcinoma

Objective: To investigate the clinicopathological, immunophenotypic and molecular features of colorectal amphicrine carcinoma (AC). Methods: Eight cases of colorectal AC were collected at the Nanjing Drum Tower Hospital and Nanjing First Hospital, Nanjing, China from 2013 to 2020. The histopathological, immunohistochemical and molecular features were analyzed. The relevant literature was reviewed. Results: There were 6 males and 2 females, with an average age of 56 years (range 28-80 years). The tumor sites were as follows: 4 cases in sigmoid colon, 3 cases in rectum, and 1 case in transverse colon. Microscopically, there were three different patterns in the tumors, including nests with collagen hyperplasia, sheets of cells with scant stroma, and glandular or cribriform growth of goblet- or signet ring-like cells. The tumor cells generally had abundant cytoplasm with abundant mucin or eosinophilic granules. The nuclei were oval or irregular with fine chromatin and inconspicuous nucleoli. Mitotic figures were common. Neuroendocrine granules and mucin granules could be identified clearly under electron microscope. All cases showed frequent perineural and lymphovascular invasions, lymphatic metastasis, and advanced stage. Regarding immunohistochemical and specific stains, the tumor cells expressed more than two neuroendocrine markers, particularly CD56 and synaptophysin which were diffusely positive in 7 of the 8 cases. They also showed intracellular mucin in the amphicrine components which was positive for D-PAS. KRAS G12C or NRAS Q61 gene mutations were found in 2 patients. Among the six cases with complete follow-up, four of them died of the disease within three years of the diagnoses, while two were alive without known disease progression. Conclusions: Colorectal AC is a rare, distinct entity with both epithelial and neuroendocrine differentiation. It mainly occurs in the sigmoid colon and rectum. It typically has aggressive clinical courses, dismal prognosis and characteristic histological features and immunophenotype, which highlight the importance of recognizing this entity for clinicians and pathologists.

An in vitro intestinal model captures immunomodulatory properties of the microbiota in inflammation

ABSTRACT Considerable effort has been put forth to understand mechanisms by which the microbiota modulates and responds to inflammation. Here, we explored whether oxidation metabolites produced by the host during inflammation, sodium nitrate and trimethylamine oxide, impact the composition of a human stool bacterial population in a gut simulator. We then assessed whether an immune-competent in vitro intestinal model responded differently to spent medium from bacteria exposed to these cues compared to spent medium from a control bacterial population. The host-derived oxidation products were found to decrease levels of Bacteroidaceae and overall microbiota metabolic potential, while increasing levels of proinflammatory Enterobacteriaceae and lipopolysaccharide in bacterial cultures, reflecting shifts that occur in vivo in inflammation. Spent microbiota media induced elevated intracellular mucin levels and reduced intestinal monolayer integrity as reflected in transepithelial electrical resistance relative to fresh medium controls. However, multiplexed cytokine analysis revealed markedly different cytokine signatures from intestinal cultures exposed to spent medium with added oxidation products relative to spent control medium, while cytokine signatures of cultures exposed to fresh media were similar regardless of addition of host-derived cues. Further, the presence of immune cells in the intestinal model was required for this differentiation of cytokine signatures. This study indicates that simple in vitro immune-competent intestinal models can capture bacterial-mammalian cross-talk in response to host-derived oxidation products and supports utility of these systems for mechanistic studies of interactions between the gut microbiome and host in inflammation.

A126 ONCE IS BY CHANCE, TWO IS A TREND: A RECURRING FINDING WITHIN THE POST-RESECTION DEFECT

Abstract Background A 74-year-old male was referred for the management of a large non-pedunculated colorectal polyp in the transverse colon. On optical evaluation, including high-definition white-light and narrow-band imaging (NBI), a 30mm 0-IIA non-granular large non-pedunculated colorectal polyps (LNPCP) was identified with optical features in keeping with adenomatous histopathology (NBI International Colorectal Endoscopic II, Japan NBI Expert Team IIA, Kudo Pit Pattern III/IV). Endoscopic mucosal resection (EMR) was performed. During sequential tissue transection and evaluation of the expanding submucosal defect a hole with a surrounding white-cautery ring was identified in keeping with significant deep mural injury. However, on careful evaluation a cystic structure was identified with a viscous amorphous substance emanating from it. Endoscopic resection of the lesion was completed with subsequent through-the-scope mechanical clip closure of the area of concern. Aims case report showing unique finding of intra-cellular mucin emanating from the post-resection defect has been identified as a potential intra-procedural finding of a mucinous adenocarcinoma Methods Endoscopic mucosal resection of a mid transverse colon polyp Results Histopathology identified a villous adenoma with high-grade dysplasia with submucosal mucin and an indeterminate focus of carcinoma; highly suspicious for a mucinous adenocarcinoma. No muscularis propria was identified. After multi-disciplinary review, the patient underwent laparoscopic right hemicolectomy with no evidence of invasive disease. Conclusions Recently coined as the “fish-eye” polypectomy defect, intra-cellular mucin emanating from the post-resection defect has been identified as a potential intra-procedural finding of a mucinous adenocarcinoma; specifically, in an otherwise benign appearing LNPCP based on real-time optical evaluation. Herein we describe the second case in the literature. This reinforces the importance of meticulous evaluation of the post-resection defect to stratify this finding from deep mural injury. Moreover, further understanding of the clinical ramifications of this unique intra-procedural finding is needed. Funding Agencies None

Клинические наблюдения эндоскопической диагностики и лечения раннего перстневидноклеточного рака желудка

Signet ring cell carcinoma is a specific histological subtype of gastric adenocarcinoma. The tumor name is due to the characteristic type of malignant cells nuclei, that take the form of a ring. Such cells contain a large amount of intracellular mucin, which shifts the nucleus to the periphery creating a typical microscopic appearance. Currently, there is no single point of view, regarding the treatment strategy of such patients, as well as the prognosis of the disease. Modern endoscopic technologies allow not only to detect signet ring cell carcinoma of the stomach at an early stage, but can also be the method of choice in the radical treatment of such patients. This clinical observation aims to demonstrate the results of endoscopic diagnosis of early signet ring cell carcinoma in two patients with different treatment approaches.

Acantholytic Squamous Cell Carcinoma

A 63-year-old Filipino man presented with a one-month history of painful ulceration on the alveolar socket of a molar tooth of the right hemimandible. The patient consulted at a tertiary hospital, where he underwent incisional biopsy.
 
 Microscopically, the biopsy specimen showed neoplastic cells arranged in a pseudoglandular alveolar pattern with cystic spaces lined with atypical polygonal cells. (Figure 1) Detached “glassy” keratinocytes which are dyskeratotic acantholytic cells were seen within these cystic spaces. (Figure 2) Areas with features of more conventional squamous cell carcinoma, i.e., intercellular bridges and abundant eosinophilic cytoplasm, were also present. (Figure 3) Immunohistochemical staining for p40 showed diffuse nuclear positivity. (Figure 4) Given these findings, a diagnosis of acantholytic squamous cell carcinoma (ASCC) was made.1
 
 Acantholytic squamous cell carcinoma (historically known as adenomatoid squamous cell carcinoma or adenoacanthoma) is a histologic variant of squamous cell carcinoma (SCC) that most often presents as an ulcer on sun-exposed areas, mostly in elderly males.1,2 ASCCs of the oral cavity are rare, with fewer than 60 cases reported in the literature.3 In a series of 55 cases describing intraoral ASCCs, the most common sites of ASCC were the tongue (24/55) and the maxilla/maxillary gingiva and/or palate (11/55).3
 
 The presence of a pseudoglandular or alveolar pattern might suggest the diagnosis of an adenocarcinoma. However, the findings of tumor lobules with a distinctly squamoid morphology, along with the presence of intercellular bridges, will point to the correct diagnosis. Furthermore, ASCC does not present with intracellular mucin, clear cells, and intermediate cells – an important distinguishing point with mucoepidermoid carcinoma. The absence of true glands also militates against the differential diagnosis of an adenosquamous carcinoma.1
 
 Although the diagnosis of ASCC may be established through histomorphology alone, p40 immunohistochemistry – a useful marker for squamous cell differentiation - strengthens the diagnosis.4 Loss of E-Cadherin expression – a protein involved in cell adhesion and binding - is usually seen in the discohesive cells but may be retained in the well differentiated areas.2 Absence of staining with mucicarmine and CD34 will help rule out mucoepidermoid carcinoma and angiosarcoma, respectively.1,2 The authors felt that the latter two differential diagnoses could be excluded on the basis of the light microscopic features present in the case along with the demonstration of diffuse p40 positivity. It is granted however that in resource-rich settings, these other ancillary diagnostic tests may prove helpful especially for morphologically ambiguous cases or cases with less tissue volume.
 
 Current studies show no statistically significant difference in the overall survival rate of ASCCs versus that of conventional SCC.3 ASCC is treated in the same manner as conventional SCC.1 The importance of recognizing this variant lies in ensuring that it is not mistaken for its other non-squamous morphological mimics.

Bronchiolar adenomas (BA) - A detailed radio-pathologic analysis of six cases and review of literature

Bronchiolar adenomas (BAs)/ciliated muco-nodular papillary tumors (CMPTs), are small, peripheral lung nodules arising predominantly in the elderly that follow a benign course. They can be mistaken for adenocarcinomas on frozen section. Immunohistochemistry (IHC) for basal cell markers highlights the continuous layer of basal cells underlying the tumor cells in BAs. BAs are further subdivided into proximal-type and distal type.Six BAs were retrieved from the pathology archives. The cases were classified based on morphology into proximal and distal BAs. The clinical and radiological features were reviewed. Immunohistochemistry and special stains were performed.The most common radiological picture of BA/CMPT was of a solid nodule with SUVmax < 3 as seen in 60% cases. 40% cases showed cavitation on CT. On histological examination, four cases were morphologically classified as proximal BAs and two as distal BAs. In proximal BAs, TTF1 was focally positive only in the basal cells in three of four. The mucin stained acidic. In distal BAs, TTF1 was diffusely positive in both basal and luminal cells. There was scant intracellular neutral mucin. Both the distal BAs had concomitant neuroendocrine tumors in the same lobe.Though the number of cases evaluated in this study is too low to be statistically significant, this study provides additional evidence to the concept of BA classification based on site specific histology and supplementary immunohistochemistry and reiterates the radiological features that may help distinguish it from malignant lesions.

Autophagy of mucin granules contributes to resolution of airway mucous metaplasia

Exacerbations of muco-obstructive airway diseases such as COPD and asthma are associated with epithelial changes termed mucous metaplasia (MM). Many molecular pathways triggering MM have been identified; however, the factors that regulate resolution are less well understood. We hypothesized that the autophagy pathway is required for resolution of MM by eliminating excess non-secreted intracellular mucin granules. We found increased intracellular levels of mucins Muc5ac and Muc5b in mice deficient in autophagy regulatory protein, Atg16L1, and that this difference was not due to defects in the known baseline or stimulated mucin secretion pathways. Instead, we found that, in mucous secretory cells, Lc3/Lamp1 vesicles colocalized with mucin granules particularly adjacent to the nucleus, suggesting that some granules were being eliminated in the autophagy pathway rather than secreted. Using a mouse model of MM resolution, we found increased lysosomal proteolytic activity that peaked in the days after mucin production began to decline. In purified lysosomal fractions, Atg16L1-deficient mice had reduced proteolytic degradation of Lc3 and Sqstm1 and persistent accumulation of mucin granules associated with impaired resolution of mucous metaplasia. In normal and COPD derived human airway epithelial cells (AECs), activation of autophagy by mTOR inhibition led to a reduction of intracellular mucin granules in AECs. Our findings indicate that during peak and resolution phases of MM, autophagy activity rather than secretion is required for elimination of some remaining mucin granules. Manipulation of autophagy activation offers a therapeutic target to speed resolution of MM in airway disease exacerbations.

Diagnostic challenges of intra-operative frozen consultation for gastrointestinal signet ring cell carcinoma†.

Signet ring cell carcinoma (SRCC) is challenging to recognise on intra-operative frozen sections, with known high false-negative rates. The objective of this study was to investigate common factors contributing to discrepancies between intra-operative frozen diagnoses and those made upon review of permanent sections, and summarise our experiences gained and lessons learned on minimising errors on intra-operative frozen diagnoses of gastrointestinal SRCC. We retrospectively examined our pathology database from 25 May 2000 to 1January 2018 and re-reviewed intra-operative frozen sections and permanent haematoxylin and eosin (H&E) slides for specimens confirmed with SRCC on permanent sections. This study includes 83 specimens taken from 50 patients, with an accuracy of 85.5%. Main common factors causing discordance or deferral in recognising SRCC between intra-operative frozen procedures and permanent sections include: (i) resemblance of clusters of SRCC cells with a myxoid background; (ii) disguise as normal or reactive cells (histiocytes, macrophages, large reactive lymphocytes, plasma cells or adipocytes) due to their relatively clear or depleted cytoplasmic mucin; and (iii) histological sampling errors, leading to misses of small foci of SRCC on frozen section slides. An accurate diagnosis of SRCC during intra-operative frozen consultations remains challenging. Based on our experiences and lessons, the most important strategies to reduce diagnostic errors are: (i) understanding the unusual histomorphological features of SRCC cells on frozen sections including, but not limited to, intracellular mucin depletion, absence of desmoplasia and no adjacent pre-cancer changes; and (ii) close attention to abrupt transition from normal architecture (e.g. glandular or submucosal loose connective tissue) to myxoid and/or inflammatory-like appearance, which potentially harbours SRCC.

Invasive Solid Mucinous Papillary Carcinoma Breast with Neuroendocrine Differentiation: A Case Report with Immunohistochemical Study

Solid papillary carcinoma of the breast (SPCB) is a distinctive form of papillary carcinoma that tends to occur in older women and usually has a favorable prognosis. We describe an invasive solid papillary carcinoma with extracellular and intracellular mucin and neuroendocrine differentiation in a 60-year old female. The cytological features have been also been highlighted with an insight on differentials that were helpful in its correct identification preoperatively.

Resolvin E1 Reduces Leukotriene B4–Induced Intracellular Calcium Increase and Mucin Secretion in Rat Conjunctival Goblet Cells

Leukotriene B4 (LTB4) is a major proinflammatory mediator important in host defense, whereas resolvins (Rvs) are produced during the resolution phase of inflammation. The authors determined the actions of both RvE1 and RvD1 on LTB4-induced responses of goblet cells cultured from rat conjunctiva. The responses measured were an increase in the intracellular [Ca2+] ([Ca2+]i) and high-molecular-weight glycoprotein secretion. Treatment with RvE1 or RvD1 for 30 minutes significantly blocked the LTB4-induced [Ca2+]i increase. The actions of RvE1 on LTB4-induced [Ca2+]i increase were reversed by siRNA for the RvE1 receptor, and the actions of RvD1 were reversed by an RvD1 receptor inhibitor. The RvE1 and RvD1 block of LTB4-stimulated increase in [Ca2+]i was also reversed by an inhibitory peptide to β-adrenergic receptor kinase. LTB4 and block of the LTB4-stimulated increase in [Ca2+]i by RvE1 and RvD1 were partially mediated by the depletion of intracellular Ca2+ stores. RvE1, but not RvD1, counterregulated the LTB4-induced high-molecular-weight glycoprotein secretion. Thus, both RvE1 and RvD1 receptors directly inhibit LTB4 by phosphorylating the LTB4 receptor using β adrenergic receptor kinase. RvE1 receptor counterregulates the LTB4-induced increase in [Ca2+]i and secretion, whereas RvD1 receptor only counterregulates LTB4-induced [Ca2+]i increase.

Resection of a Posterior Fossa Endodermal Cyst With Exoscopic Assistance: 2-Dimensional Operative Video.

Neurenteric cysts are rare benign congenital tumors of endodermal origin that most commonly occur in the cervical and upper thoracic spine, with only about 10% to 18% of the reported cases occurring intracranially.1 A definitive preoperative diagnosis is complicated by the variable appearance of neurenteric cysts on magnetic resonance (MR) imaging.2 The recommended treatment of neurenteric cysts is complete surgical resection when possible.3,4 We present a case of a posterior fossa neurenteric cyst. A 33-yr-old man without medical history presented with left-sided headache and mild left-sided facial numbness and weakness. Admission MR imaging revealed a nonenhancing mass, which was hyperintense on T1-weighted MR images, compressing the brainstem anteriorly. The lesion was isointense on T2 FLAIR images and hypointense on diffusion-weighted imaging, initially read as possible epidermoid cyst. The patient underwent a left-sided retrosigmoid craniotomy via far lateral transcondylar approach. The tumor was adjacent to both vertebral arteries, the left PICA, and cranial nerves (CN) VII-XII with superior extension to CN V. The cyst was encased in a thin capsule, and its contents were yellowish in color and ranged from thick liquid to colloidal and caseous consistency. The cyst also contained heavily calcified portions, which were excised using sharp dissection. Images of the cyst wall show that it is focally lined with ciliated columnar epithelium with intracellular mucin confirming an endodermal or neurenteric cyst. After the operation, the patient's symptoms resolved, and he was discharged on postoperative day 4. Postoperative MR images confirmed gross total resection. The patient consented to video production.

Alterations to Mucus Production and Secretion during Giardia Infection Involve Giardia Protease Activity and PAR2 Activation

BackgroundThe protozoan parasite Giardia duodenalis has been shown to disrupt the intestinal mucus barrier via unknown mechanisms, potentially disrupting host mucosal immunity and contributing to development of post‐infectious disorders. Protease‐activated receptor 2 (PAR2) has been identified as a potential target for secreted Giardia cysteine proteases, and may play a role in disruption of mucus production and secretion in the intestines.MethodsThe human colonic epithelial cell line LS174T was infected with Giardia trophozoites (isolates NF, WB, S2, and GSM). Prior to infection, trophozoites were treated with E64, a broad‐spectrum cysteine protease inhibitor, and LS174T were treated with a pepducin PAR2 antagonist, BAPTA, a calcium chelator, or U0126, an ERK1/2 inhibitor. MUC2 mucin gene expression was assessed using quantitative PCR (qPCR), and intracellular mucin content was quantified by staining with fluorescein‐coupled wheat germ agglutinin (WGA) and imaging using confocal microscopy.Chinese hamster ovary cells transfected with nano‐luciferase tagged PAR2 were incubated with Giardia trophozoites. Release of enzymes due to cleavage at the receptor N‐terminus by Giardia resulted in a luminescent signal proportional to the number of cleaved receptors.Wild type (WT) and PAR2 deficient (PAR2 −/−) mice were infected with Giardia trophozoites. The colonic mucus layer was stained using WGA and qPCR was performed for Muc2 and Muc5ac in the small and large intestines.ResultsGiardia NF, S2, and WB, but not GSM, upregulate MUC2 expression in LS174T cells. This increase was attenuated by inhibition of Giardia cysteine proteases and by antagonism of PAR2 or inhibition of calcium release or ERK1/2 signaling in LS174T cells. Preliminary results suggest that WGA staining is decreased upon exposure of LS174T to Giardia NF trophozoites.Giardia trophozoites cleaved PAR2 at the N‐terminus, suggesting they are capable of activating the receptor. The amount of cleavage was isolate‐dependent, reflecting differences in protease activity, and cleavage was significantly reduced by E64 treatment for all isolates.Giardia infected WT mice show increased Muc2 and Muc5ac expression in the colon, and increased Muc5ac but decreased Muc2 expression in the jejunum. These changes were not seen in PAR2−/− mice. Both WT infected and PAR2−/− non‐infected mice showed thinning of the colonic mucus layer compared to WT controls. There was some recovery in thickness in PAR2−/− infected mice.ConclusionsGiardia‐induced alterations to mucin gene expression in vitro and in vivo are dependent on PAR2 signaling. Giardia cysteine proteases cleave and activate PAR2, leading to both calcium release and MAPK pathway activation, which in turn contributes to altered gene transcription. Further, Giardia induces altered mucus secretion in vitro, which may contribute to thinning of the colonic mucus gel in vivo. Further study is required to determine the role of PAR2 in mucus secretion during Giardia infection.Support or Funding InformationCrohn’s Colitis Canada

Conjunctival 'mucoepidermoid carcinoma' revisited: a revision of terminology, based on morphologic, immunohistochemical and molecular findings of 14 cases, and the 2018 WHO Classification of Tumours of the Eye.

In 2018, the consensus meeting for the WHO Classification of Tumours of the Eye decided that conjunctival mucoepidermoid carcinoma should be reclassified as adenosquamous carcinoma, as this represented a better morphological fit. To examine the applicability of this terminology, we studied the clinical, histopathological, immunohistochemical and molecular pathology of 14 cases that were originally diagnosed as conjunctival mucoepidermoid carcinoma. There were 7 (50%) females and 7 (50%) males. The median age was 64 years. The left eye was affected in 8 and the right eye in 6 patients. In-situ carcinoma was present in 11/14 (79%) cases and comprised in-situ squamous cell carcinoma (SCC) and conjunctival intraepithelial neoplasia with mucinous differentiation (CIN-Muc). Invasive carcinoma was present in 11/14 (79%) cases. Group 1 (1/11 cases, 9%) comprised invasive SCC only. Group 2 (6/11 cases, 55%) comprised SCC with mucinous differentiation, manifesting as scattered intracellular mucin, occasionally together with intercellular mucin, with no evidence of true glandular differentiation. Group 3 (3/11 cases. 27%) comprised true adenosquamous carcinoma. Group 4 (1/11 cases, 9%) comprised pure adenocarcinoma. Thirteen of 14 cases (93%) underwent FISH for MAML2 translocation and none were rearranged. Two cases harboured high-risk HPV (type 16 and 18). The combined findings confirm that all lesions in our study were not mucoepidermoid carcinoma, but represented predominantly SCC with mucinous differentiation and adenosquamous carcinoma. We, therefore, recommend future revision of the WHO classification to include SCC with mucinous differentiation alongside adenosquamous carcinoma.