SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: Virchows Archiv : an international journal of pathology

28

Testicular Sertoli cell tumors are rare and usually sporadic and unifocal. The large cell calcifying Sertoli cell tumor variant is known to be associated with Carney and Peutz-Jeghers syndromes and can be bilateral in these patient populations. There has been no documented association of Sertoli cell tumor with familial adenomatous polyposis (FAP) in the literature. The case presented is a bilateral Sertoli cell tumor occurring in a 34-year-old patient with FAP. The tumor had a conventional Sertoli cell tumor morphology, but with different morphology in the left and right sites. Beta-catenin immunostain showed strong nuclear reactivity in the tumor cells but not the nonneoplastic Sertoli cells. The presence of bilaterality as well as overexpression of beta-catenin by this tumor supports an association of the development of Sertoli cell tumor with the patient’s FAP syndrome and adenomatous polyposis coli inactivation.

Concepts: Oncology, Testicle, Spermatozoon, Sertoli cell, Blood-testis barrier, Familial adenomatous polyposis, Sertoli-Leydig cell tumour, Sertoli cell nodule

27

Trophoblast cell adhesion and migration are carefully coordinated during normal placental development. We have compared the expression of three adhesion molecules, E-cadherin, β-catenin, and Lewis x, by immunohistochemistry during normal trophoblast differentiation, and in hydatidiform moles and choriocarcinomas. Both E-cadherin and β-catenin were expressed in normal placenta cytotrophoblast, and this expression decreased with trophoblast maturation. E-cadherin was mainly localized along the contact between cytotrophoblast and syncytiotrophoblast, which indicates its role in the differentiation of the syncytial layer. Lewis x disappeared progressively during differentiation of normal villous vessels, and was expressed in molar pregnancies. Interestingly, whereas choriocarcinomas were not, or poorly, stained, invasive hydatidiform moles (invHMs) strongly expressed Lewis x in vascular structures. This observation correlated well with E-cadherin and β-catenin expression and suggests that these three markers are associated with the invasive transformation. The presence of robust endothelial structures in invHMs could also explain their ability to maintain organized villous architecture (contrary to metastatic choriocarcinomas) during their invasion of extrauterine tissues such as the lung or the brain after dissemination through the blood flow. In our hands, Lewis x appeared to be a new, reliable marker that can be used to clearly distinguish invHMs from choriocarcinomas.

Concepts: Gene expression, Developmental biology, Placenta, Human chorionic gonadotropin, Hydatidiform mole, Choriocarcinoma, Trophoblast, Syncytiotrophoblast

26

Colorectal cancer (CRC) can be divided into non-mucinous and mucinous subtypes, of which the latter portends to have a worse clinical prognosis. A previous study suggested a putative link between SOX2 expression observed selectively in mucinous CRC and the induction of the gastric mucin MUC5AC. In this study, we re-evaluated the expression behavior of SOX2, MUC5AC, and CDX2 in both types of CRC. We performed immunohistochemical analysis on 90 cases of non-mucinous CRCs, 57 cases of mucinous CRCs, and 15 case-matched normal intestinal mucosa. In contrast to the previously suggested link between SOX2 and mucinous CRC, we observe aberrant expression of SOX2 at equal levels in both subtypes. Fluorescence in situ hybridization (FISH) analysis shows that expression is not attributed to genomic amplification. While SOX2 and CDX2 are normally expressed in a reciprocal manner, SOX2-positive tumor cells co-express CDX2. Furthermore, we show that MUC5AC is expressed independently of SOX2. In conclusion, we show that aberrant SOX2 expression is specifically linked neither to mucinous CRCs nor to the induction of MUC5AC, in contrast to previous suggestions.

Concepts: Scientific method, Gene expression, Cancer, Mucous membrane, Anatomical pathology, Colorectal cancer, Tumor, In situ hybridization

18

Malignant pleural mesothelioma is a rare tumor with a poor prognosis. The only universally recognized pathological prognostic factor is histopathological subtype with a shorter survival in non-epithelioid subtypes. Recently, a grading of epithelioid mesothelioma on surgical resection has been proposed. The aim of our work is to assess the prognostic role of several histopathological factors on a retrospective cohort of 116 patients diagnosed as a pleural mesothelioma for more than 95% of patients on pleural biopsy. Our work shows that mitotic count <3/10 HPF (p < 0.0001), the lack of necrosis (p = 0.0379), mild nuclear atypia (p = 0.0054), the lack of atypical mitoses (p = 0.0265), a nucleoli size <3 μm (p = 0.0139), and a nucleoli absent or visible at 200× or higher magnification (p = 0.0170) are significantly associated with a better median overall survival in epithelioid mesothelioma. The presence of atypical mitoses was found to be related to a worse median survival in non-epithelioid mesothelioma. Mitotic count, necrosis, nuclear atypia, and nucleoli size are not associated with overall survival in non-epithelioid mesothelioma. Our work highlights that histopathological prognostic factors can be assessed on pleural biopsies and can predict reliably median overall survival. This is of interest in order to define subgroups of patients who could benefit of different therapies and select patients who could benefit of surgical excision.

Concepts: Cancer, Medical terms, Pathology, Surgery, Anatomical pathology, Histopathology, Mesothelioma, Cytopathology

11

Although sudden cardiac death (SCD) is one of the most important modes of death in Western countries, pathologists and public health physicians have not given this problem the attention it deserves. New methods of preventing potentially fatal arrhythmias have been developed and the accurate diagnosis of the causes of SCD is now of particular importance. Pathologists are responsible for determining the precise cause and mechanism of sudden death but there is still considerable variation in the way in which they approach this increasingly complex task. The Association for European Cardiovascular Pathology has developed these guidelines, which represent the minimum standard that is required in the routine autopsy practice for the adequate investigation of SCD. The present version is an update of our original article, published 10 years ago. This is necessary because of our increased understanding of the genetics of cardiovascular diseases, the availability of new diagnostic methods, and the experience we have gained from the routine use of the original guidelines. The updated guidelines include a detailed protocol for the examination of the heart and recommendations for the selection of histological blocks and appropriate material for toxicology, microbiology, biochemistry, and molecular investigation. Our recommendations apply to university medical centers, regionals hospitals, and all healthcare professionals practicing pathology and forensic medicine. We believe that their adoption throughout Europe will improve the standards of autopsy practice, allow meaningful comparisons between different communities and regions, and permit the identification of emerging patterns of diseases causing SCD. Finally, we recommend the development of regional multidisciplinary networks of cardiologists, geneticists, and pathologists. Their role will be to facilitate the identification of index cases with a genetic basis, to screen appropriate family members, and ensure that appropriate preventive strategies are implemented.

Concepts: Medicine, Causality, Myocardial infarction, Pathology, Anatomical pathology, Cardiac arrest, Sudden cardiac death, Forensic pathology

6

Rearrangements of the ROS1 gene occur in 1-2 % of non-small cell lung cancers (NSCLCs). Crizotinib, a highly effective inhibitor of ROS1 kinase activity, is now FDA-approved for the treatment of patients with advanced ROS1-positive NSCLC. Consequently, focus on ROS1 testing is growing. Most laboratories currently rely on fluorescence in situ hybridisation (FISH) assays using a dual-colour break-apart probe to detect ROS1 rearrangements. Given the rarity of these rearrangements in NSCLC, detection of elevated ROS1 protein levels by immunohistochemistry may provide cost-effective screening prior to confirmatory FISH testing. Non-in situ testing approaches also hold potential as stand-alone methods or complementary tests, including multiplex real-time PCR assays and next-generation sequencing (NGS) platforms which include commercial test kits covering a range of fusion genes. In order to ensure high-quality biomarker testing, appropriate tissue handling, adequate control materials and participation in external quality assessment programmes are essential, irrespective of the testing technique employed. ROS1 testing is often only considered after negative tests for EGFR mutation and ALK gene rearrangement, based on the assumption that these oncogenic driver events tend to be exclusive. However, as the use of ROS1 inhibitors becomes routine, accurate and timely detection of ROS1 gene rearrangements will be critical for the optimal treatment of patients with NSCLC. As NGS techniques are introduced into routine diagnostic practice, ROS1 fusion gene testing will be provided as part of the initial testing package.

Concepts: Genetics, Gene expression, Cancer, Mutation, Molecular biology, Lung cancer, Non-small cell lung carcinoma, Fluorescent in situ hybridization

3

Alterations in SMARCA4, a member of the chromatin remodeling Switch Sucrose Non-Fermentable (SWI/SNF) complex, characterize a subset of non-small cell lung cancer (NSCLC), but detailed morphological and immunophenotypic description of this tumor type is lacking. We describe 20 NSCLC cases found on routine screening not to express SMARCA4 by immunohistochemistry (IHC). These tumors were stained for CK7, TTF1, SMARCA2, SMARCA4, SMARCB1, and HepPar-1 and analyzed for molecular alterations, using a 160 cancer-related gene panel including the full coding sequence of SMARCA4. Patients were eight females and 12 males aged 41 to 76 (median, 60). Of 18 tumors with detailed data, 14 presented with synchronous distant metastases (M1). Histological examination showed predominantly solid adenocarcinoma (n = 15), frankly rhabdoid (n = 3) and mucinous (n = 2) patterns. Except for the rhabdoid cases, all tumors showed at least focal unequivocal glands and lacked squamous differentiation, justifying a diagnosis of adenocarcinoma. IHC showed a distinctive uniform immunophenotype (CK7(+)/HepPar-1(+)/TTF1(-)) in 18/20 cases. Only 2/16 cases showed limited weak expression of neuroendocrine markers. EGFR mutations and EML4-ALK and ROS1 gene rearrangements were not found in any of the examined cases. Next-generation sequencing, using a 160 cancer-related gene panel, revealed concurrent SMARCA4 and TP53 mutations in nine of the 12 (75%) successfully tested cases. Our study highlights (1) the morphological diversity of SMARCA4-deficient lung adenocarcinoma, (2) the consistent absence of expression of TTF1 in the presence of expression of HepPar-1, (3) absence of EGFR driver mutations, and (4) frequent inactivating SMARCA4 mutations as underlying mechanism of the observed SMARCA4 protein loss. SMARCA4-deficient pulmonary adenocarcinoma is emerging as a distinctive, albeit phenotypically heterogeneous molecular subgroup of TTF1-negative NSCLC. Uniform HepPar-1 expression in this subset of NSCLC may represent a diagnostic pitfall and merits further studies to explore the mechanisms involved.

Concepts: DNA, Cancer, Lung cancer, Non-small cell lung carcinoma, Histology, Neoplasm, Adenocarcinoma, Immunohistochemistry

2

Traditionally, surgical pathology reports are narrative. These report types are prone to error and missing data; therefore, structured standardized reporting was introduced. However, the effect of synoptic reporting on the completeness of esophageal and gastric carcinoma pathology reports is not yet established.

1

The spectrum of the renal oncocytic tumors has been expanded in recent years to include several novel and emerging entities. We describe a cohort of novel, hitherto unrecognized and morphologically distinct high-grade oncocytic tumors (HOT), currently diagnosed as “unclassified” in the WHO classification. We identified 14 HOT by searching multiple institutional archives. Morphologic, immunohistochemical (IHC), molecular genetic, and molecular karyotyping studies were performed to investigate these tumors. The patients included 3 men and 11 women, with age range from 25 to 73 years (median 50, mean 49 years). Tumor size ranged from 1.5 to 7.0 cm in the greatest dimension (median 3, mean 3.4 cm). The tumors were all pT1 stage. Microscopically, they showed nested to solid growth, and focal tubulocystic architecture. The neoplastic cells were uniform with voluminous oncocytic cytoplasm. Prominent intracytoplasmic vacuoles were frequently seen, but no irregular (raisinoid) nuclei or perinuclear halos were present. All tumors demonstrated prominent nucleoli (WHO/ISUP grade 3 equivalent). Nine of 14 cases were positive for CD117 and cytokeratin (CK) 7 was either negative or only focally positive in of 6/14 cases. All tumors were positive for AE1-AE3, CK18, PAX 8, antimitochondrial antigen, and SDHB. Cathepsin K was positive in 13/14 cases and CD10 was positive in 12/13 cases. All cases were negative for TFE3, HMB45, Melan-A. No TFEB and TFE3 genes rearrangement was found in analyzable cases. By array CGH, complete chromosomal losses or gains were not found in any of the cases, and 3/9 cases showed absence of any abnormalities. Chromosomal losses were detected on chromosome 19 (4/9), 3 with losses of the short arm (p) and 1 with losses of both arms (p and q). Loss of chromosome 1 was found in 3/9 cases; gain of 5q was found in 1/9 cases. On molecular karyotyping, 3/3 evaluated cases showed loss of heterozygosity (LOH) on 16p11.2-11.1 and 2/3 cases showed LOH at 7q31.31. Copy number (CN) losses were found at 7q11.21 (3/3), Xp11.21 (3/3), Xp11.22-11.21 (3/3), and Xq24-25 (2/3). CN gains were found at 13q34 (2/3). Ten patients with available follow up information were alive and without disease progression, after a mean follow-up of 28 months (1 to 112 months). HOT is a tumor with unique morphology and its IHC profile appears mostly consistent. HOT should be considered as an emerging renal entity because it does not meet the diagnostic criteria for other recognized eosinophilic renal tumors, such as oncocytoma, chromophobe renal cell carcinoma (RCC), TFE3 and TFEB RCC, SDH-deficient RCC, and eosinophilic solid and cystic RCC.

1

The lymphatic circulation is still a somewhat forgotten part of the circulatory system. Despite this, novel insights in lymph angiogenesis in health and disease, application of immune markers for lymphatic growth and differentiation and also the introduction of new imaging techniques to visualize the lymphatic circulation have improved our understanding of lymphatic function in both health and disease, especially in the last decade. These achievements yield better understanding of the various manifestations of lymph oedemas and malformations, and also the patterns of lymphovascular spread of cancers. Immune markers that recognize lymphatic endothelium antigens, such as podoplanin, LYVE-1 and Prox-1, can be successfully applied in diagnostic pathology and have revealed (at least partial) lymphatic differentiation in many types of vascular lesions.

Concepts: Immune system, Blood, Lymph node, Heart, Blood vessel, Lymphatic system, Cardiovascular system, Ibn al-Nafis