Two cases of malignant peritoneal mesothelioma without asbestos exposure: cytologic and immunohistochemical features

Cytological Assessment of Desmoplastic Malignant Pleural Mesothelioma in an Autopsy Case

INTRODUCTION

Desmoplastic malignant pleural mesothelioma (DMPM) is a sarcoma-type mesothelioma, comprising approximately 5% of malignant pleural mesotheliomas. Although effusion cytology is commonly used as the primary diagnostic approach for mesothelioma, it may not be useful for DMPM because of the presence of desmoplasia and bland cellular atypia. We report a case, and previously undescribed cytological features, of DMPM that was diagnosed during autopsy.

CASE PRESENTATION

A man in his 60s with a history of occupational asbestos exposure was referred to our hospital with right chest pain. A chest CT scan showed right pleural effusion. Thirteen months later, the patient died of respiratory failure. During autopsy, scrape-imprint smears were prepared and cytology of pleural effusions was performed. The scrape-imprint smear samples showed spindle cells with mild nuclear atypia and grooves with fibrous stroma. Pleural effusion cytology revealed spindle cells with mild nuclear atypia, as well as grooves with loose epithelial connections. Histological examination of the right pleura showed spindle cells proliferating with dense collagen fibers, as seen in the cytological samples, thus indicating a diagnosis of DMPM, which was confirmed by fluorescence in situ hybridization.

CONCLUSION

Cytological procedures such as pleural effusion cytology and scrape-imprinting cytology may help in diagnosing rare tumors such as DMPM.

Expression of estrogen receptor beta (ERβ) and its prognostic value in pleural mesothelioma

Background

Overexpression of estrogen receptors in malignant pleural mesothelioma has shown an independent relation with a better prognosis of survival, and the use of selective estrogen receptor beta (ERβ) agonists increases the susceptibility to antitumor treatment.

Methods

This was a retrospective single center study that analyzed the response of malignant pleural mesothelioma with an expression of ERβ to first-line chemotherapy. The study included patients with pleural mesothelioma pathologically confirmed between 2013 and 2016 at the National Institute for Respiratory Disease (INER), who underwent an immunohistochemistry assay for ERβ (mouse monoclonal antibody PPG5/10). The primary endpoint was the response to chemotherapy based on RECIST 1.1 according to the ERβ expression; secondary outcomes were the overall survival (OS) and progression-free survival (PFS).

Results

We included 22 patients, regarding the expression of ERβ, 17 (77.2%) patients had high or moderate degree, while 5 (22.7%) had low degree or null expression. The response to treatment as by RECIST 1.1, 12 (54.5%) had partial response, 5 (22.7%) had stable disease, and 3 (13.6%) had progression. None of the patients had a complete response. Of those who had a partial response, 9 (75%) had a high or moderate degree of ERβ expression in tumor cells, and 3 (25%) had a low or null degree of expression.

Conclusions

High and moderate expression of ERβ group with advanced clinical stage malignant pleural mesothelioma was associated with a tendency of higher OS and better response to chemotherapy treatment resulting in longer PFS although statistical significance was not achieved.

Pemetrexed-loaded nanoparticles targeted to malignant pleural mesothelioma cells: an in vitro study

PURPOSE

Malignant pleural mesothelioma (MPM) is an aggressive tumor characterized by poor prognosis. Its incidence is steadily increasing due to widespread asbestos exposure. There is still no effective therapy for MPM. Pemetrexed (Pe) is one of the few chemotherapeutic agents approved for advanced-stage disease, although the objective response to the drug is limited. The use of gold nanoparticles (GNPs) as a drug delivery system promises several advantages, including specific targeting of malignant cells, with increased intracellular drug accumulation and reduced systemic toxicity, and, in the case of MPM, direct treatment administration into the pleural space. This study aims at exploring CD146 as a potential MPM cell-specific target for engineered Pe-loaded GNPs and to assess their effectiveness in inhibiting MPM cell line growth.

METHODS

MPM cell lines and primary cultures obtained by pleural effusions from MPM patients were assayed for CD146 expression by flow cytometry. Internalization by MPM cell lines of fluorescent dye-marked GNPs decorated with a monoclonal anti CD146 coated GNPs (GNP-HC) was proven by confocal microscopy. The effects of anti CD146 coated GNPs loaded with Pe (GNP-HCPe) on MPM cell lines were evaluated by cell cycle (flow cytometry), viability (MTT test), clonogenic capacity (soft agar assay), ROS production (electric paramagnetic resonance), motility (wound healing assay), and apoptosis (flow cytometry).

RESULTS

GNP-HC were selectively uptaken by MPM cells within 1 hour. MPM cell lines were blocked in the S cell cycle phase in the presence of GNP-HCPe. Both cell viability and motility were significantly affected by nanoparticle treatment compared to Pe. Apoptotic rate and ROS production were significantly higher in the presence of nanoparticles. Clonogenic capacity was completely inhibited following nanoparticle internalization.

CONCLUSION

GNP-HCPe treatment displays in vitro antineoplastic action and is more effective than Pe alone in inhibiting MPM cell line malignant phenotype. The innovative use of specifically targeted GNPs opens the perspective of local intrapleural administration to avoid normal cell toxicity and enhance chemotherapy efficacy.

Diffuse malignant peritoneal mesothelioma

Mesothelioma often originates in the pleura and less frequently in the peritoneum. This article describes a rare case of diffuse malignant peritoneal mesothelioma in a 54-year-old male construction worker who was admitted to our hospital with a 2-month history of progressive abdominal distention. Abdominal computed tomography revealed extensive peritoneal nodularity and omental cake along with massive ascites. Imaging findings initially suggested peritoneal carcinomatosis, primary peritoneal carcinoma, and tuberculous peritonitis. Laparoscopic biopsy of the omentum and peritoneum confirmed the diagnosis of malignant peritoneal mesothelioma of epitheloid type. Although systemic chemotherapy was administered, no tumor regression was found. The patient finally died of nosocomial infection.

N -Methyl- N -nitrosourea-induced Renal Tumors in Rats: Immunohistochemical Comparison to Human Wilms Tumors

N-Methyl-N-nitrosourea (MNU)-induced renal tumors in rats and Wilms tumors in humans were compared. Renal mesenchymal tumors (RMTs) and nephroblastomas (blastemal and epithelial components) in female Lewis rats treated with a single intraperitoneal injection of 50 mg/kg MNU at birth and Wilms tumors (blastemal, epithelial and mesenchymal components) in humans were analyzed for the expression of pancytokeratin (CK), vimentin, p63, α-smooth muscle actin (SMA), desmin, S-100, CD57, CD117/c-kit, Wilms tumor 1 protein (WT1) and β-catenin. The mesenchymal components of rat RMTs and human Wilms tumors expressed vimentin, SMA and β-catenin. The blastemal components of rat nephroblastomas and human Wilms tumors expressed vimentin, CD117/c-kit and β-catenin. The epithelial components of rat nephroblastomas and human Wilms tumors expressed vimentin and β-catenin. WT1 was expressed in different cellular components of rat tumors as compared with human Wilms tumors; the expression was seen in mesenchymal tumors and blastemal components of nephroblastomas in rats and epithelial components in human Wilms tumors. CK, p63 and CD57 were not expressed in rat RMTs or nephroblastomas, while CK and WT1 were expressed in epithelial components and CD57 was expressed in blastemal and epithelial components of human Wilms tumors. Rat and human tumors were universally negative for the expression of desmin and S-100. The immunohistochemical characteristics of rat renal tumors and human Wilms tumors may provide valuable information on the differences in renal oncogenesis and biology between the two species.

Oestrogen receptors are prognostic factors in malignant peritoneal mesothelioma

BACKGROUND

Malignant peritoneal mesothelioma (MPM) is a rare and fatal cancer. Females are found to survive longer than males after treatment, suggesting a possible involvement of hormonal factors. Estradiol is involved in cellular proliferation of a number of cancers and acts mainly through oestrogen receptors (ERs). Hence, we examined the expression of oestrogen receptors with correlation to prognosis.

METHODS

Oestrogen receptors expression was examined using immunohistochemistry on 42 paraffin-embedded sections of MPM tumours. Kaplan-Meier survival curves were analysed to determine the significance of ER expression in relation to prognosis.

RESULTS

ER-β (nuclear) was detected in 33 (79 %) patients. ER-β was also detected in the cellular cytoplasm of 9 (21 %) patients. Presence of ER-β (nuclear) was associated with favourable survival (univariate analysis, P = 0.001), whereas the presence of ER-β (cytoplasm) was associated with a poor survival (P = 0.014). Multivariate Cox regression analysis revealed the absence of ER-β (nuclear) and the presence of ER-β (cytoplasm) to be independent predictive factors for poor disease outcome (hazard ratio 5.4, 95 % confidence interval 1.86-15.75; P = 0.002 and hazard ratio 8.0, 95 % confidence interval 1.8-34; P = 0.005), respectively. ER-α (nuclear) was detected in only 4 (9 %) of patients and not statistically significant (univariate analysis, P = 0.066).

CONCLUSION

The presence of ER-β (cytoplasm) is associated with poor prognosis. The favourable survival association observed in patients with ER-β (nuclear) raises a question about the molecular mechanisms of the tumorigenic roles of ER-β in each cellular compartment and requires further studies.