Reactive Mesothelial Hyperplasia Research Articles

Diagnostic utility of BAP1 and EZH2 expression in malignant mesothelioma.

Malignant mesothelioma is a highly aggressive cancer that is usually diagnosed at advanced stages; thus, highly sensitive and specific markers are necessary for its early definitive diagnosis. The aim of this study was to evaluate the diagnostic utility and prognostic significance of BAP1 and EZH2 in malignant mesothelioma. The expression of BAP1 and EZH2 was investigated by immunohistochemistry in 32 malignant mesotheliomas and 44 benign mesothelial proliferative lesions, including well-differentiated papillary mesothelioma (n = 4), mesothelial inclusion cyst (n = 22), and reactive mesothelial hyperplasia (n = 18). BAP1 loss and high EZH2 expression were observed in 17 (53%) and 22 (66%) malignant mesothelioma cases, respectively, whereas none of the benign lesions showed BAP1 loss or high EZH2 expression. The combination of BAP1 loss and high EZH2 expression as markers to differentiate epithelioid/biphasic malignant mesothelioma from benign mesothelial lesions was highly sensitive (90%) and specific (100%). There were no statistically significant associations between parameters such as age and sex of patients, tumour location, asbestos exposure, treatment, histology, and BAP1 or EZH2 expression. Survival analysis revealed that BAP1 loss, but not high EZH2 expression, was associated with a better prognosis. BAP1 loss and high EZH2 expression were highly specific to malignant mesothelioma in differentiating it from benign mesothelial proliferations, and the combination of these two markers improved the diagnostic accuracy.

Diagnostic Utility of Epithelial Membrane Antigen (EMA) and Calretinin (CAL) in Effusion Cytology.

Fluid cytology and subsequent utilization of immunocytology on cell block is being used commonly for increasing the diagnostic accuracy in effusion cytology. To do cytological analysis of fluids and evaluate the role of Epithelial Membrane Antigen (EMA) and Calretinin (CAL) to differentiate between reactive and malignant cell in pleural and peritoneal fluids. This was a prospective study carried out in Department of Pathology, Shri Guru Ram Rai Institue of Medical and Health Science, for a period of 18 months from January 2014 to June 2015. A total of 253 samples of pleural and peritoneal fluid were studied by May-Gruenwald-Giemsa (MGG) stain and Papanicolaou (Pap) staining. In 73 cases which were suspicious for malignancy, cell blocks were prepared and IHC was done using two immunomarkers- EMA and CAL. A total of 253 cases of effusion cytology were studied out of which 73 were found positive for malignant cells. Maximum cases of malignant cells or atypical cells were seen in peritoneal fluid. A total of 34 cases were histologically positive for malignancy. All these cases showed strong membranous and cytoplasmic positivity for EMA. Most of cases also showed 2%-5% positivity for CAL. There were 38 cases categorized as atypical or reactive mesothelial cell hyperplasia. These cases showed nuclear and cytoplasmic staining for calretinin and none of these were positive for EMA, although 5 cases showed score 2-3, which was considered as negative. The distinction between reactive and malignant mesothelial cells in cytological specimens can be problematic. A combination of CAL and EMA may help in accurate diagnosis.

Immunohistochemical detection of MTAP and BAP1 protein loss for mesothelioma diagnosis: Comparison with 9p21 FISH and BAP1 immunohistochemistry

ObjectivesDifferentiating malignant pleural mesothelioma (MPM) from reactive mesothelial hyperplasia (RMH) is still challenging. Detection of homozygous deletion (HD) of 9p21 region including p16INK4A (p16) by fluorescence in situ hybridization (FISH) and immunohistochemical detection of loss of BRCA1 associated protein 1 (BAP1), are reliable markers for MPM diagnosis. However, not all laboratories are equipped to perform 9p21 FISH; immunohistochemistry (IHC) is a more common and feasible technique. Thus, we sought to develop a IHC-based method that could predict the deletion of p16 in MPM in concordance with 9p21 FISH. Materials and methodsWe examined the expression of the 9p21.3-related proteins (p14, p15, p16, and methylthioadenosine phosphorylase (MTAP)) and BAP1 using IHC in 51 MPM and 25 RMH cases, and assessed their correlation with HD of p16 detected by FISH. The diagnostic usefulness of IHC of the 9p21.3-related proteins and BAP1 and their combinations was assessed using the cut-off values set by receiver operating characteristic (ROC) analysis. ResultsAmong the 9p21.3-related proteins, MTAP IHC findings showed best concordance with 9p21 FISH results (kappa coefficient of 0.69) and a specificity of 100%. We also examined the combinations of MTAP IHC with the other products. The loss of p16 and MTAP had better concordance (kappa coefficient of 0.71), although lower specificity (85%). For differentiating MPM from RMH, only MTAP showed 100% specificity among the 9p21.3-related proteins, as did BAP1 IHC and 9p21 FISH. Among BAP1 combinations, only that of BAP1 with MTAP showed 100% specificity. Its sensitivity was 76.5%, which was lower than BAP1 IHC and 9p21 FISH combination (84.3%), but higher than BAP1 IHC alone (60.8%) or 9p21 FISH alone (60.8%). ConclusionsA combination of MTAP or BAP1 loss detected by IHC can likely detect MPM with good sensitivity and 100% specificity, and serve as useful ancillary IHC for discriminating MPM from RMH.

Value of E-cadherin and desmin immunohistochemistry in distinguishing metastatic adenocarcinoma from reactive mesothelial hyperplasia in serous effusion

Value of E-cadherin and desmin immunohistochemistry in distinguishing metastatic adenocarcinoma from reactive mesothelial hyperplasia in serous effusion

Exuberant mesothelial proliferation mimicking malignant mesothelioma in a patient with prolonged VP shunt: A case report

Background: Ventriculo-peritoneal shunt (VP shunt) surgery is the most widely used procedure in the treatment of hydrocephalus. Common complications post-VP shunt insertion are infection, mechanical failure, as well as functional complications such as overor underdrainage. Rarely, abdominal complications can present remotely after the time of VP shunt insertion. We found no reportsin the literature describing peritoneal exuberant mesothelial hyperplasia mimicking mesothelioma, clinically, radiologically, andpathologically in a setting of VP shunt.Case: A 22-year-old female with a history of T cell lymphoma in 2002, suffered from CNS recurrence and increased intracranialpressure (ICP) in 2004 necessitating a VP shunt insertion. In 2015, she presented with abdominal pain. CT scan of the abdomenshowed omental nodular lesions that were biopsied and read first by a private pathology center as atypical mesothelial proliferationfavoring malignant mesothelioma. However, after reviewing the full medical history and evaluating additional surgical materialfrom the patient, review of the pathology specimen at the American University of Beirut concluded that the final diagnosis isatypical mesothelial proliferation favoring exuberant mesothelial hyperplasia possibly as a reaction to the long-standing VPshunt.Conclusion: It is often difficult for the pathologist to differentiate a malignant from a reactive mesothelial hyperplasia especiallyon biopsies or limited material due to sampling issues. Many features of reactive mesothelial hyperplasia can mimic malignantmesothelioma. This complication took place in the setting of a VP shunt.

BAP1 immunohistochemistry and p16 FISH results in combination provide higher confidence in malignant pleural mesothelioma diagnosis: ROC analysis of the two tests.

Differentiation of malignant pleural mesothelioma (MPM) from benign mesothelial proliferation remains problematic. Loss of nuclear staining of BRCA1-associated protein 1 (BAP1; detected using immunohistochemistry (IHC)) and homozygous deletion (HD) of p16 (detected using fluorescence in situ hybridization (FISH)) are useful for differentiation of MPM from reactive mesothelial hyperplasia (RMH), but the correlation between BAP1 expression loss and p16 HD has not been fully described. We performed BAP1 IHC and p16-specific FISH for 40 MPM and 20 RMH cases, and measured proportions of cells showing BAP1 expression and p16 HD for each case. The diagnostic accuracy for MPM and the cut-off values of the two methods were assessed using receiver operating characteristic (ROC) analysis. BAP1 expression loss, p16 HD and coexistence of both were present in 27 (67.5 %), 27 (67.5 %) and 17 (42.5 %) MPM cases, respectively. Three MPM cases (7.5 %) and all 20 RMH cases had neither BAP1 loss nor p16 HD. There was no correlation between the results of the two methods. Their combination showed higher sensitivity (92.5 %, 37/40) and estimated probability than BAP1 IHC and p16-specific FISH used alone. BAP1 IHC and p16-specific FISH have independent diagnostic value, and have increased reliability when used in combination, for MPM diagnosis.

Low homozygous/high heterozygous deletion status by p16 FISH correlates with a better prognostic group than high homozygous deletion status in malignant pleural mesothelioma

ObjectivesHomozygous deletion (homo-d) of the p16 (CDKN2A) gene, as determined by fluorescence in situ hybridization (FISH), helps differentiate malignant pleural mesothelioma (MPM) from reactive mesothelial hyperplasia (RMH). Heterozygous deletion (hetero-d) has also been identified variably in p16 FISH. This study aimed to investigate the significance of homo-d and hetero-d of p16 in the diagnosis and prognosis of MPM. Materials and methodsp16 FISH was performed in 93 MPMs and 47 RMHs. Real-time polymerase chain reaction (PCR) and methylation specific PCR (MSP) were also performed for cases in which DNA was available. Overall survival (OS) was assessed via the Kaplan-Meier method and logrank test. ResultsCutoff values for homo-d and hetero-d were set at 10% and 47%, respectively, based on p16 FISH results in RMH. In MPM, 80/93 (86.0%) were homo-d positive, and 15/93 (16.1%) were hetero-d positive. No RMH was homo/hetero-d positive. In nine cases of MPM with the low homo-d (<30%)/high hetero-d (>47%) pattern, FISH with a shorter probe caused a slight increase (from 20.1% to 26.5%) in the mean percentage of homo-d and a decrease in that of hetero-d (from 59.6% to 55.6%). Four cases in which the low homo-d/high hetero-d pattern was maintained with the shorter probe were further analyzed by real-time PCR, which separated them into a two (n=2) or one allele deletion group (n=2). MSP revealed no promoter methylation in the two cases with one allele deletion. The OS was significantly shorter in homo-d positive cases (n=24) than homo-d negative cases (n=5, p=0.0002) in the 29 MPM cases with follow-up data. Also, low homo-d/high hetero-d cases (n=5) had a significantly better prognosis than high homo-d (≥30%) cases (n=17, p=0.011). ConclusionsWithin p16 homo-d positive MPMs with poorer prognosis, the low homo-d/high hetero-d pattern may belong to a better prognostic subgroup in homo-d positive MPMs.

Use of Anti-Noxa Antibody for Differential Diagnosis between Epithelioid Mesothelioma and Reactive Mesothelial Hyperplasia

Objectives: The histological differential diagnosis between epithelioid mesothelioma (EM) and reactive mesothelial hyperplasia (RMH) is not always straightforward. The aim of the present study was to search for new immunohistochemical markers to distinguish EM from RMH. Methods: We evaluated and compared the expression of apoptosis-related genes in EM and RMH by real-time RT-PCR array analysis followed by clustering of significant gene expression. Immunohistochemical staining and statistical analysis of Noxa expression in 81 cases of EM and 55 cases of RMH were performed and compared with the utility of other previously reported antibodies such as Desmin, EMA, GLUT-1, IMP-3 and CD146. Results: Noxa mRNA expression levels were found to be increased in EM when compared to RMH by RT-PCR array analysis. In the immunohistochemical analysis, Noxa showed sensitivity of 69.0%, specificity of 93.6% and positive predictive value of 93.0% as a positive marker of EM in distinguishing it from RMH, and these values were almost similar to IMP-3. Conclusion: Noxa is a marker with relatively high specificity, and can be used to distinguish EM from RMH. It would be a valuable addition to the current antibody panel used for the differential diagnosis of EM and RMH.

Peritoneal malignant mesothelioma (PMM), and primary peritoneal serous carcinoma (PPSC) and reactive mesothelial hyperplasia (RMH) of the peritoneum. Immunohistochemical and fluorescence in situ hybridisation (FISH) analyses

AimsPeritoneal malignant mesothelioma (PMM) is an uncommon tumour, accounting for only 7–9% of all mesotheliomas in Japan. Differential diagnosis between PMM and primary peritoneal serous carcinoma (PPSC), a high-grade serous...

Epithelial membrane antigen in differential diagnosis of malignant mesothelioma, metastatic adenocarcinoma, and reactive mesothelial hyperplasia

Epithelial membrane antigen in differential diagnosis of malignant mesothelioma, metastatic adenocarcinoma, and reactive mesothelial hyperplasia

Deletion status of p16 in effusion smear preparation correlates with that of underlying malignant pleural mesothelioma tissue.

Differentiating malignant pleural mesothelioma (MPM) cells morphologically from reactive mesothelial hyperplasia cells is problematic. Homozygous deletion (HD) of p16 (CDKN2A), detected by FISH, is a good marker of malignancy and is useful to differentiate between these cells. However, the correlation between the p16 status of effusion smears and that of the underlying MPM tissues has not been investigated. We used p16-specific FISH to investigate 20 cases of MPM from which both effusion cytologic smears and histologic specimens were available. In five cases, histologic specimens included both an invasive component and surface mesothelial proliferation. In 14 cases (70%), MPM cells in both tissue sections and effusion smears were p16 HD-positive. Conversely, MPM cells in the remaining six tumors (30%) were p16 HD-negative in both tissue sections and effusion smears. For all five MPM cases with surface mesothelial proliferations and invasive components, the effusion smears, surface mesothelial proliferations, and invasive MPM components all displayed p16 deletion. Moreover, the extent to which p16 was deleted in smears highly correlated with the extent of p16 deletion in tissues. The p16 deletion percentages were also similar among smears, tissue surface proliferations, and invasive components. In cases with clinical and radiologic evidence of a diffuse pleural tumor, detection of p16 deletion in cytologic smear samples may permit MPM diagnosis without additional tissue examination. However, the absence of p16 deletion in cytologic smear samples does not preclude MPM.

P16/CDKN2A FISH in Differentiation of Diffuse Malignant Peritoneal Mesothelioma From Mesothelial Hyperplasia and Epithelial Ovarian Cancer.

It can be difficult to differentiate diffuse malignant peritoneal mesothelioma (DMPM) from reactive mesothelial hyperplasia (RMH) or peritoneal dissemination of gynecologic malignancies, such as epithelial ovarian cancer (EOC), which cause a large amount of ascites. Detection of the homozygous deletion of p16/CDKN2A (p16) by fluorescence in situ hybridization (FISH) is an effective adjunct in the diagnosis of malignant pleural mesothelioma. The aim of this study was to investigate the ability of the p16 FISH assay to differentiate DMPM from RMH and EOC. p16 FISH was performed in 28 DMPMs (successful in 19), 30 RMHs, and 40 EOC cases. The cutoff values of p16 FISH were more than 10% for homozygous deletion and more than 40% for heterozygous deletion. According to the above criteria, nine (47.4%) of 19 successful DMPM cases were homozygous deletion positive, and three (15.8%) of 19 were heterozygous deletion positive, whereas all RMH cases were negative for the p16 deletion. In all four major histologic subtypes of EOC, neither p16 homozygous nor heterozygous deletions were detected. To differentiate DMPM from RMH or EOC, the sensitivity of the p16 homozygous deletion was 32% (9/28), and the specificity was 100%. Our study suggests that p16 FISH analysis is useful in differentiating DMPM from RMH and EOC when homozygous deletion is detected.

SPLENIC CYST

Background: Splenic cysts are rare in children. They are classified into primary and secondary, also called pseudocysts. The primary feature capsule and can be congenital, vascular or neoclassical. The diagnosis, in most cases, is incidental because it is asymptomatic clinical status. The diagnosis is confirmed by Ultrasound and / or Computed Tomography (CT) of the abdomen. Case Report: Patient, I.T.S.A, female, 11 years old, complains of increasing abdominal size. The diagnosis of splenic cyst was confirmed with an exploratory laparotomy. The pathology suggests reactive mesothelial hyperplasia. The patient underwent a total splenectomy and recovered without complications. Conclusions: Splenic cysts are incidental findings, most of the times it has been an asymptomatic clinical status. In the clinical case described, the patient showed a significant increase in the abdomen. She underwent exploratory laparotomy and, consequently, total splenectomy, which is the standard treatment in cases of giants splenic cysts.

Is the cytodiagnosis of mesothelioma any easier these days?

Is the cytodiagnosis of mesothelioma any easier these days?

Well-Differentiated Papillary Mesothelioma of the Peritoneum

Abstract Objectives: Well-differentiated papillary mesothelioma of the peritoneum (WDPMP) is an uncommon subtype of epithelioid mesothelioma. Usually, WDPMP has a benign course, while a few patients have multiple recurrence and malignant transformation on long-term follow-up. The histology of WDPMP has been well studied compared with the cytology. Although accurate diagnosis is based only on histology and immunohistochemical stains, knowledge of the cytologic features of WDPMP in context with clinical and radiologic features is essential to predict a preoperative diagnosis and guide proper management, after excluding reactive mesothelial hyperplasia, malignant mesothelioma, and serous neoplasms of the ovaries and peritoneum. Surgical excision gives a favorable outcome. Methods: We describe a case of 28-year-old woman who sought treatment for chronic lower abdominal pain, dysuria, and dyspareunia. Results: Radiologic findings suggested multiple metastatic peritoneal deposits. Ultrasound-guided fine-needle aspiration cytology showed many papillae, tubulopapillary and spheroid groups, monolayered pavement-like sheets, and many dispersed cells. Papillae showed many layers of round to ovoid cells, with minimal atypia. Atypical mitoses and necrosis were not found. A cytologic diagnosis of WDPMP was suggested. After complete resection of all the tumor nodules, histopathology and immunohistochemical findings were compatible with WDPMP. On follow-up, she developed tumor recurrence at 9 months and was managed successfully with adjuvant chemotherapy. Conclusions: This article highlights the cytologic features of WDPMP with relevant review of the literature and differential diagnosis.

Peritoneal Malignant Mesothelioma Metastatic to Supraclavicular Lymph Nodes

Distinguishing between malignant mesothelioma and reactive mesothelial hyperplasia is often inestimable, but may be a challenging gauntlet for pathologists. A 62-year-old man underwent appendectomy after the identification of a peritoneal mass and the histological examination showed mesothelial proliferation along the appendix surface with no clear images of infiltration. After a few months the patient developed mediastinal and supraclavicular lymphadenopathies, and a nodal biopsy showed mesothelial cell proliferation invading lymphatic sinuses, consistent with the cells seen in the abdominal cavity. Since overt morphologic criteria for malignancy were lacking and reactive mesothelial cell deposits have been documented in lymph nodes, a molecular investigation of the CDKN2A (henceforth simply p16) gene status via fluorescence in situ hybridization was performed, which showed homozygous deletion in 100% tumor cells. These data ruled out the hypothesis of reactive mesothelial cells inclusion in lymph nodes, thus confirming the diagnosis of epithelioid malignant mesothelioma.

P53 Expression in a Malignant Mesothelioma Patient during Seven-Year Follow-up.

Malignant mesothelioma (MM) is the aggressive tumor of serosal surfaces. There are crude pathogenetic results regarding the biology of MM. Coordinated upregulations of p53 gene expression are shown in malignancies. We believed that there are changes in the p53 expression with transformation from reactive hyperplasia to MM. A 65-year-old male was admitted the hospital because of left pleuritic chest pains in 2004. Chest computed tomography (CT) results showed left pleural effusions with loculation and pleural thickening. Pathologic findings revealed reactive mesothelial hyperplasia. In 2008, the patient again felt left pleuritic chest pains. Chest CT showed progressive thickening of the left pleura. Pathologic diagnosis was atypical mesothelial hyperplasia. In 2011, chest CT showed progressive thickening of his left pleura. He was diagnosed with well-differentiated papillary mesothelioma. Serial change was analyzed by immunohistochemical staining for p53 of pleural tissues. There were no remarkable changes in p53 expressions during the transformation to MM.

Differential Expression of Extracellular Matrix Constituents and Cell Adhesion Molecules between Malignant Pleural Mesothelioma and Mesothelial Hyperplasia

Malignant pleural mesothelioma (MPM) is a highly aggressive neoplasm associated with asbestos exposure. Currently, the molecular mechanisms that induce MPM development are still unknown. The purpose of this study was to identify new molecular biomarkers for mesothelial carcinogenesis. We analyzed a panel of 84 genes involved in extracellular matrix remodeling and cell adhesion by polymerase chain reaction (PCR) array in 15 samples of epithelioid mesothelioma and 10 samples of reactive mesothelial hyperplasia (MH; 3 of 25 samples were inadequate for mRNA analysis). To validate the differentially expressed genes identified by PCR array, we analyzed 27 more samples by immunohistochemistry, in addition to the 25 samples already studied. Twenty-five genes were differentially expressed in MPM and MH by PCR array. Of these we studied matrix metalloproteinase 7 (MMP7), MMP14, CD44, and integrin, alpha3 expression by immunohistochemistry in 26 epithelioid MPM and 26 MH samples from the entire series of 52 cases. We observed higher MMP14 and integrin, alpha3 expression in MPM samples compared with MH samples (p = 0.000002 and p = 0.000002, respectively). Conversely, CD44 expression was low in most (57.7%) mesothelioma samples but only in 11.5% of the MH samples (p = 0.0013). As regards MMP7, we did not observe differential expression between MH and MPM samples. We have extensively studied genes involved in cell adhesion and extracellular matrix remodeling in MPM and MH samples, gaining new insight into the pathophysiology of mesothelioma. Moreover, our data suggest that these factors could be potential biomarkers for MPM.

Pleuroscopic Punch Biopsy Using Insulated-Tip Diathermic Knife-2 for the Diagnosis of Desmoplastic Malignant Mesothelioma

Desmoplastic malignant mesothelioma (DMM) is a rare subtype of malignant pleural mesothelioma (MPM) and is often difficult to distinguish from pleural fibrosis and reactive mesothelial hyperplasia, especially if the biopsy samples are small. We performed full-thickness pleural biopsy on a lesion suspected to be DMM using an insulated-tip diathermic knife-2 (IT knife-2) during flex-rigid pleuroscopy. IT knife-2 is a novel electrosurgical device for endoscopic submucosal dissection in the early gastrointestinal cancer. It consists of a needle knife with 3 short blades at the distal end attached to an insulated ceramic tip. A 54-year-old man presenting with chest wall mass and thickened pleura, in whom a computed tomography-guided percutaneous needle aspiration had remained negative, underwent flex-rigid pleuroscopy for definitive diagnosis. While applying electric current, we used the IT knife-2 to incise the pleura in a circular shape just above the endothoracic fascia. The incised pleura was removed by forceps and examined pathologically. The microscopic examination was compatible with DMM. We discovered that pleuroscopic punch biopsy using IT knife-2 can diagnose DMM. Use of IT knife-2 during flex-rigid pleuroscopy can obtain sufficient samples from densely thickened pleura, which is difficult to diagnose with small biopsies.

Expression of glucose transporter protein 1 and desmin in reactive mesothelial hyperplasia and epithelioid malignant mesothelioma

To investigate the expression of glucose transporter protein 1 (GLUT-1) and desmin in benign and malignant mesothelial lesions, including reactive mesothelial hyperplasia (RMH), epithelioid malignant mesothelioma (EMM) and metastatic adenocarcinoma (MAC). One hundred and forty two pleural biopsy specimens were collected in this study, including 58 cases of RMH, 53 cases of EMM and 31 cases of MAC. Immunohistochemical EliVision method was performed to detect GLUT-1 and desmin expression. The positive rates for GLUT-1 in RMH, EMM and MAC were 13.8% (8/58) , 81.1% (43/53) and 77.4% (24/31) , respectively, with statistically significant differences between RMH and others (both P < 0.01). The positive rates for desmin in RMH, EMM and MAC were 77.6% (45/58) , 9.4% (5/53) and 0 (0/31) , respectively, with statistically significant difference between RMH and others (both P < 0.01). The combined expression pattern of positive GLUT-1 and negative desmin was found in 1 (1.7%, 1/58) RMH cases, 41 (77.4%, 41/53) EMM cases and 24 (77.4%, 24/31) MAC cases, with statistically significant difference between RMH and others (both P < 0.01). GLUT-1 and desmin may be used as immunohistochemical markers in separating RMH from EMM. Combined application of two antibodies may improve the specificity.