Surgical treatment of malignant pleural mesothelioma: a review

Diffuse malignant mesothelioma of the peritoneum: a clinicopathological study of 35 patients treated locoregionally at a single institution

BACKGROUND

In the current study, the authors report the clinicopathologic features of patients with peritoneal diffuse malignant mesothelioma (DMM) who were treated in a uniform fashion at a single institution to assess prognostic factors.

METHODS

Thirty-five patients were treated with cytoreductive surgery (CRS) and intraperitoneal hyperthermic perfusion (IPHP). The tumors were classified into epithelial, sarcomatoid, and biphasic types. Immunohistochemistry stains were performed for calretinin, WT-1, pCEA, Ber-EP4, epidermal growth factor receptor (EGFR), p16, matrix metalloprotease-2 (MMP-2), and MMP-9. Statistical correlation was evaluated for age, gender, completeness of cytoreduction (CC), tumor histotype, mitotic count (MC), necrosis, nuclear grade (NG), and biologic markers with regard to overall survival (OS) and progression-free survival (PFS).

RESULTS

The patient group was comprised of 15 men and 20 women with a median age of 52 years (range, 24-73 yrs). Twenty-five patients underwent optimal cytoreduction. There were 32 epithelial tumors and 3 biphasic tumors, and 3 patients had an NG of 1, 19 had an NG of 2, and 13 had an NG of 3. The mean MC was 14.1 (range, 0-160 per 50 high-power fields). Necrosis was present in 11 cases. All the tumors were found to be positive for calretinin and WT-1 and were negative for pCEA and Ber-EP4. The NG and MC were found to be significantly associated with OS (P = 0.02 and P = 0.01, respectively) whereas CC was found to be associated with both OS (P = 0.05) and PFS (P = 0.03). No biologic markers were found to be of prognostic significance.

CONCLUSIONS

The results of the current study indicate that NG, MC, and CC may be useful prognostic factors in patients treated with CRS and IPHP. The expression of EGFR, MMP-2, and MMP-9 and absent and/or reduced expression of p16 in DMMs confirms the results of previous studies suggesting their role in tumor pathogenesis and kinetics.

Prognostic Significance of Vascular Endothelial Growth Factor, Tumor Necrosis, and Mitotic Activity Index in Malignant Pleural Mesothelioma

OBJECTIVES

Tumor growth and metastasis are angiogenesis-dependent events, and several prognostic factors have been determined in malignant mesothelioma. In this study, we investigated the prognostic significance of vascular endothelial growth factor (VEGF), tumor necrosis (TN), and mitotic activity index (MAI) in malignant mesothelioma. For the first time (to our knowledge), we also demonstrated the association between VEGF staining, TN, and MAI in malignant mesothelioma.

METHODS

Decortication and VATS materials of 40 patients were investigated. The routinely processed formalin-fixed, paraffin-embedded, hematoxylin-eosin-stained tumor sections that had been used for the original diagnostic purposes were retrieved. Hematoxylin-eosin sections were selected for VEGF immunostaining, TN, and mitotic count. Clinicopathologic data, stage of disease, and survival of patients were all determined. The correlations between variables were evaluated by Spearman rank correlation test. Both univariate analysis using the log-rank test and multivariate analysis using Cox regression model were performed for survival analysis.

RESULTS

There was a significant correlation between VEGF staining and TN (r = 0.42, p = 0.006). In univariate analysis, both VEGF staining (p = 0.0002) and TN (p = 0.0055) showed significant correlation with short survival. Also, there was a positive correlation between VEGF and tumor stage (p = 0.046). In multivariate analysis, only VEGF was determined as an independent prognostic factor in malignant mesothelioma (p = 0.001). There was no association between MAI and survival (p = 0.504).

CONCLUSIONS

VEGF, known as an important angiogenic peptide, is an independent prognostic factor in malignant pleural mesothelioma. TN stimulates angiogenesis, and we observed a significant correlation between VEGF and TN. However, further studies are needed to evaluate the prognostic significance of angiogenic properties in malignant mesothelioma.

Malignant Pleural Mesothelioma: A Case Report

OBJECTIVE

The aim of this study was to discuss a case of malignant pleural mesothelioma (MPM) that presented to a chiropractic teaching clinic and review the pathophysiology of diseases associated with asbestos exposure.

CLINICAL FEATURES

An 86-year-old woman had right-sided back pain at the thoracolumbar junction for 3 months; this pain prevented her from exercising on a daily basis. She was alert and oriented but in obvious distress because of her back pain. Breath sounds were decreased on the right in the posterior and lower lobes, with dull percussion and increased tactile fremitus. A significant collection of pleural effusion was seen on the right side on plain film radiographs. A chest computed tomography with contrast showed a large right-sided pleural effusion with small consolidation at the right lung base suggestive of pleural or pulmonary malignancy and highly suspicious for MPM. Further questioning about asbestos exposure revealed that her husband was a maintenance worker. An extrapleural pneumonectomy was performed, and specimens of parietal and visceral pleura were sent for pathological, which revealed a definitive diagnosis of spindle cell mesothelioma.

INTERVENTION AND OUTCOME

The patient was diagnosed with MPM, and a surgical therapy option was considered because of the aggressive nature of the lesion and her advanced age. An extrapleural pneumonectomy was performed with removal of parietal and visceral pleura, right lower lobe, and right hemidiaphragm.

CONCLUSION

This is an unusual case of advanced MPM that is most likely from indirect asbestos exposure.

Advances in the diagnosis, evaluation, and management of malignant pleural mesothelioma

Malignant mesothelioma is an insidious neoplasm arising from the mesothelial surfaces of the pleural and peritoneal cavities, the pericardium, or the tunica vaginalis. A total of 80% of all cases are pleural in origin. The predominant cause of malignant mesothelioma is inhalational exposure to asbestos, although evidence is increasing to support the hypothesis that simian virus-40 virus plays a role in cocarcinogenesis. Immunohistochemical markers such as calretinin, WT-1, and cytokeratin 5/6 are becoming established diagnostic markers. Preliminary data suggests that a soluble form of mesothelin could serve as a serum marker for established and early cases of mesothelioma. Positron emission tomography with 18-fluorodeoxyglucose in conjunction with computed tomograhy scanning has improved preoperative imaging and staging. Prognostic factors have been identified and verified. Negative indicators include thrombocytosis, high leukocyte counts, poor performance status, and nonepithelial histology. For the first time, there is now evidence that some treatments are increasing the quality and quantity of life for patients with mesothelioma. Chemotherapy, with the new multi-targeted antifolate drug Pemetrexed, combined with cisplatin, has shown superior survival rates in a large phase III trial when compared to cisplatin alone. High-dose intensity-modulated radiotherapy when administered after extrapleural pneumonectomy has resulted in excellent local control. Multimodality treatment programs that combine surgical cytoreduction with novel forms of radiation therapy and more effective chemotherapy combinations may offer significant increases in survival for certain subgroups of mesothelioma patients. Innovative palliative approaches have proved successful in alleviation of the significant symptoms experienced by many mesothelioma patients. Experimental treatments such as immunotherapy and gene therapy present a window of hope for all mesothelioma patients, and in the future, may be combined with 'standard therapy' in multimodality protocols. Patients with adequate performance status should be enrolled into clinical trials where possible. Over the past decade, significant advances have been made on several fronts that have improved the ability to diagnose a stage, define prognosis, and treat malignant pleural mesothelioma.

A phase II study evaluating the cisplatin and epirubicin combination in patients with unresectable malignant pleural mesothelioma

Few chemotherapeutic agents have demonstrated their efficacy in malignant mesothelioma. The cisplatin plus doxorubicin combination has one of the highest response rates. Epirubicin is an anthracyclin, analogous to doxorubicin, with a different toxicologic pattern. As there are no data on the activity of the combination cisplatin plus epirubicin in malignant mesothelioma, the European Lung Cancer Working Party (ELCWP) designed a phase II study with response rate as primary objective. Sixty-nine eligible patients with malignant pleural mesothelioma were centrally registered. The majority of the patients were male (n=59), had a Karnofsky performance status of 80 or more (n=62) and presented with an epithelial histologic subtype (n=43). Median age was 62 years. In nine patients, metastases were documented at the initial work-up, mainly in bone, lung and skin. Three hundred and twenty-four cycles of chemotherapy were administered. The main toxicities were nausea and vomiting, neutropenia and alopecia. Among 63 assessable patients, response rate was 19.0% (95% confidence interval [CI] 9-29%). Median survival was 13.3 months. In multivariate analysis, poor prognostic factors for survival were neutrophil count and CALGB groups 4-6. In conclusion, cisplatin plus epirubicin appears as an effective regimen in malignant mesothelioma, with a favourable toxicity profile. However, it does not demonstrate superior activity to other active regimens in this disease.

Hemithoracic radiation therapy after pleurectomy/decortication for malignant pleural mesothelioma

PURPOSE

To evaluate pleurectomy/decortication (P/D) and adjuvant radiotherapy (RT) in the treatment of malignant pleural mesothelioma (MPM).

METHODS AND MATERIALS

In a retrospective review, we included MPM patients treated with P/D and adjuvant RT at Memorial Sloan-Kettering Cancer Center from 1974 to 2003. When indicated, patients received intraoperative brachytherapy to residual tumor.

RESULTS

All 123 patients received external beam RT (median dose, 42.5 Gy; range, 7.2-67.8 Gy) to the ipsilateral hemithorax postoperatively. Fifty-four patients underwent brachytherapy (matched peripheral dose, 160 Gy). The median and 2-year overall survival for all patients was 13.5 months (range, 1-199 months) and 23%, respectively. One-year actuarial local control for all patients was 42%. Multivariate analysis for overall survival revealed radiation dose <40 Gy (p = 0.001), nonepithelioid histology (p = 0.002), left-sided disease (p = 0.01), and the use of an implant (p = 0.02) to be unfavorable. Two patients (1.6%) died from Grade 5 toxicity within 1 month of treatment.

CONCLUSIONS

Pleurectomy/decortication with adjuvant radiotherapy is not an effective treatment option for patients with MPM. Our results imply that residual disease cannot be eradicated with external RT with or without brachytherapy and that a more extensive surgery followed by external RT might be required to improve local control and overall survival.

Mitogen-activated protein kinase expression and activation does not differentiate benign from malignant mesothelial cells

BACKGROUND

In vitro studies of malignant mesothelioma (MM) cells have suggested activation of mitogen-activated protein kinase (MAPK) in response to asbestos exposure. The objective of this study was to investigate protein expression (level) and phosphorylation status (activity) of the extracellular-regulated kinase (ERK), the c-Jun amino-terminal kinase (JNK), and the high-osmolarity glycerol response kinase (p38) in vivo through the analysis of fresh frozen reactive mesothelium (RM) and MM specimens.

METHODS

MAPK levels were analyzed in 36 fresh-frozen MM specimens (32 effusions, 4 biopsies) and in 14 RM specimens (all effusions) using immunoblotting with antibodies detecting the total (pan-) and activated (phospho-) fraction (p-) of ERK, JNK, and p38. Values for pan-MAPK and p-MAPK expression and the p-MAPK/pan-MAPK ratio in MM and RM specimens were compared. Results were corroborated using immunocytochemistry for p-ERK, p-JNK, and p-38 in selected specimens.

RESULTS

Pan-ERK, pan-JNK, and pan-p38 expression was found frequently in both MM specimens (35 of 36 specimens) and RM specimens (14 of 14 specimens) using immunoblotting, with comparable findings for activated p-p38 (34 of 36 MM specimens, 13 of 14 RM specimens). Activation of p-ERK (27 of 36 MM specimens, 10 of 14 RM specimens) and p-JNK (25 of 36 MM specimens, 10 of 14 RM specimens) was less frequent. Pan-ERK (P = 0.016), pan-JNK (P = 0.004), pan-p38 (P = 0.012), and p-ERK (P = 0.02) expression levels were higher in MM specimens from female patients. Pan-p38 expression levels also were higher in peritoneal MM specimens (P = 0.019). MM and RM showed similar MAPK expression, activation, and activation ratios (Mann-Whitney test; P > 0.05). Immunocytochemistry localized MAPK to MM and RM cells.

CONCLUSIONS

The current results provided the first evidence of in vivo activation of MAPK in clinical MM and RM. The similar values in these two cell types suggest that MAPK may not be involved in the transformation of benign to malignant mesothelium, thus bringing into question the validity of using MAPKs as molecular therapeutic targets in patients with MM.

Laminin-induced signaling in tumor cells

Laminin is the main non-collagenous glycoprotein found in the basement membrane. The various laminin isoforms are involved in many physiological and pathological processes, including cancer dissemination. The interaction of cancer cells with laminin was identified as a key event in tumor invasion and metastasis. Laminin effects are mediated by laminin receptors that are divided into two groups: integrin and non-integrin receptors. Activation of a specific signal transduction pathway in the cell depends on various factors and may be altered when normal tissue becomes neoplastic. Laminin signals via multiple signal transduction pathways involving various components such as G-proteins, intracellular calcium, phospholipase D, mitogen activated protein kinases, phosphatases, focal adhesion kinase, small GTPases of the Rho family, and cytoskeleton components. This review focuses on the role of laminin in tumor progression, its signaling via the non-integrin 67kDa laminin receptor and via integrins and the reciprocal relations between these receptors in certain tumors.

Farnesyltransferase inhibitors and human malignant pleural mesothelioma: a first-step comparative translational study

It is known that the potential clinical use of farnesyltransferase inhibitors (FTI) could be expanded to include cancers harboring activated receptor tyrosine kinases. Approximately 70% of malignant pleural mesotheliomas (MPM) overexpress epidermal growth factor receptors (EGFR) and a subset express both EGFR and transforming growth factor alpha (TGF-alpha), suggesting an autocrine role for EGFR in MPM. We checked on MPM cells (10 human cell lines, 11 primary cultures obtained by human biopsies, and 7 short-term normal mesothelial cell cultures) concerning the following: (a) the relative overexpression of EGFR (Western blotting, flow cytometry, immunohistochemistry), (b) the relative expression of EGFR ligands (EGF, amphiregulin, TGF-alpha, ELISA), (c) the relative increase of the activated form of Ras (Ras-bound GTP) after EGF stimulation (Ras activation assay), (d) the efficacy of five different FTIs (HDJ2 prenylation, cell cytotoxicity, and apoptosis using ApopTag and gel ladder). EGFR was overexpressed in MPM cells compared with normal pleural mesothelial cells in equivalent levels as in non-small cell lung cancer cells A459. MPM cells constitutively expressed EGFR ligands; however, Ras activation was attenuated at high EGF concentrations (100 ng/mL). Growth of MPM cells was substantially not affected by treatment with different FTIs (SCH66336, BMS-214662, R115777, RPR-115135, and Manumycin). Among these, BMS-214662 was the only one moderately active. BMS-214662 triggered apoptosis in a small fraction of cells (not higher than 30%) that was paralleled by a slight decrease in the levels of TGF-alpha secreted by treated MPM cells. Our data highlighted the concept that the same signaling pathway can be regulated in different ways and these regulations can differ between different cells of different origin.

Immunotherapy of Murine Malignant Mesothelioma Using Tumor Lysate–pulsed Dendritic Cells

RATIONALE

Exploiting the immunostimulatory capacities of dendritic cells holds great promise for cancer immunotherapy. Currently, dendritic cell-based immunotherapy is evaluated clinically in a number of malignancies, including melanoma and urogenital and lung cancer, showing variable but promising results.

OBJECTIVE

To evaluate if pulsed dendritic cells induce protective immunity against malignant mesothelioma in a mouse model.

METHODS

Malignant mesothelioma was induced in mice by intraperitoneal injection of the AB1 mesothelioma cell line, leading to death within 28 days. For immunotherapy, dendritic cells were pulsed overnight either with AB1 tumor cell line lysate, AB1-derived exosomes, or ex vivo AB1 tumor lysate, and injected either before (Days -14 and -7) at the day of (Day 0) or after (Days +1 and +8) tumor implantation.

MAIN RESULTS

Mice receiving tumor lysate-pulsed dendritic cells before tumor implantation demonstrated protective antitumor immunity with prolonged survival (> 3 months) and even resisted secondary tumor challenge. Tumor protection was associated with strong tumor-specific cytotoxic T-lymphocyte responses. Adoptive transfer of splenocytes or purified CD8+ T lymphocytes transferred tumor protection to unimmunized mice in vivo. When given after tumor implantation in a therapeutic setting, pulsed dendritic cells prevented mesothelioma outgrowth. With higher tumor load and delayed administration after tumor implantation, dendritic cells were no longer effective.

CONCLUSIONS

We demonstrate in this murine model that immunotherapy using pulsed dendritic cells may emerge as a powerful tool to control mesothelioma outgrowth. In the future, immunotherapy using dendritic cells could be used as adjuvant to control local recurrence after multimodality treatment for malignant mesothelioma.

Current chemotherapeutic treatment of malignant pleural mesothelioma

Malignant pleural mesothelioma is an aggressive malignancy which is almost always fatal; median survival is usually < 1 year. Most patients present with symptoms including pain, dyspnoea, pleural effusions and chest wall masses. Until recently, there has been no effective treatment which can improve symptoms and prolong survival. This article reviews recent developments in the treatment of mesothelioma, particularly advances in drug therapy and the use of the current most active drug combination: pemetrexed and cisplatin. Pemetrexed is a novel antifolate drug with multiple enzyme targets. The combination of pemetrexed and cisplatin demonstrated a survival advantage over cisplatin alone in patients with pleural mesothelioma, and can give symptomatic benefits. This combination has become the standard of care in mesothelioma treatment.

Surgical management of malignant pleural mesothelioma: a systematic review and evidence summary

An evidence summary was developed for the surgical management of adult patients with diffuse or localized malignant pleural mesothelioma. This evidence summary is based on a systematic search and review of the literature published between 1985 and February 2004. Relevant studies were identified, according to pre-determined criteria by the authors and methodologists. No randomized controlled trials comparing pleurectomy (PL) with extrapleural pneumonectomy (EPP) or comparing surgery with an alternative treatment were identified. Four comparative studies, seven non-comparative prospective studies, and 16 retrospective case series were identified that looked at PL, or EPP, or PL and EPP. Trial results were not pooled due to the heterogeneity of the treatments in the trials and the fact that no trials were randomized and none were designed to directly compare different treatments. External feedback was obtained from Ontario clinicians, and the provincial Lung Cancer Disease Site Group approved the review.

CONCLUSIONS

The role of surgery in the management of malignant pleural mesothelioma cannot be precisely defined as the lack of randomized controlled clinical trials makes it impossible to determine whether the use of EPP or PL improves survival or effectively palliates the symptoms of the disease. Future studies of the role of surgery in the treatment of mesothelioma should include evaluations of quality of life.

Differential expression of the 67 kilodalton laminin receptor in epithelioid malignant mesothelioma and carcinomas that spread to serosal cavities

Expression of the 67-kd laminin receptor (67-kd LR) has been reported in a wide range of carcinomas, in many of which it correlated with poor differentiation, metastasis, disease progression, and poor survival. Malignant mesothelioma (MM) is a locally aggressive and highly lethal tumor of serosal cavities that is rarely associated with clinically detectable metastasis to distant organs. The aim of this study was to analyze the expression of the 67-kd LR in epithelioid MM and carcinomas in effusions. Effusions from patients diagnosed with ovarian (=24) and breast (=38) adenocarcinomas and MM (=24) (total = 86) were analyzed for 67-kd LR protein expression, using immunocytochemistry. The 67-kd LR mRNA expression was additionally analyzed in 21 MM effusions using reverse transcription-polymerase chain reaction (RT-PCR). Protein expression of the 67-kd LR was frequently detected in carcinomas (19/24 ovarian tumors, 79%; 15/38 breast tumors, 39%), but was rare in MM (2/24 cases, 8%), despite the presence of mRNA transcripts for the receptor in all 21 specimens studied using RT-PCR. Nine benign effusions that were additionally studied for protein expression were uniformly negative, as were all reactive mesothelial cells in malignant effusions. Our results suggest that the 67-kd LR may aid in the differential diagnosis between metastatic carcinoma, mainly of ovarian origin, and MM. They additionally suggest that the failure of MM to express the 67-kd LR protein, as opposed to the frequent expression in carcinomas with proven metastatic capacity, may be one of the factors contributing to the reduced ability of the former tumor to metastasize to distant organs.

Innovative therapies: photodynamic therapy

Photodynamic diagnosis could be a useful tool for improving the diagnostic yield of tumor biopsy, especially for mesothelioma tumors that are sclerotic and particularly hypocellular. For PDD, the use of low doses of a sensitizing drug, such as 5-ALA, must be investigated further. The initial results of 5-ALA-mediated PDD are promising. The role, if any, for PDT in the treatment of mesothelioma has yet to be established. The number of centers exploring this technology is limited because the procedure is labor intensive and requires not only specialized equipment but also physician support. The number of patients treated in the different trials is small, and no definitive conclusions can be drawn. Further complicating the interpretation of published results is the number of variables (i.e., type of sensitizer, light dose, drug dose, drug light interval, methods of light measurement, technique of light delivery, surgical debulking techniques), which differ between studies. Most reports are phase I and II studies. The final outcome of these studies with respect to survival is of limited value. The only phase III study, which was performed with an earlier generation photosensitizer, reported no advantage to the use of PDT in combination with surgery and immunochemotherapy. To date, the most that can be said is that intraoperative PDT can be performed safely in experienced centers and that there are some encouraging results, especially in patients with stages I and II MPM, particularly with the newer generation photosensitizers. One attractive aspect of this adjuvant treatment is that PDT, as opposed to some of the other adjuvant treatments combined with surgery, may offer the option of effecting adequate tumor debulking with a pulmonary-sparing procedure.

Heparanase and basic fibroblast growth factor are co-expressed in malignant mesothelioma

Heparanase is an endoglycosidase that degrades heparan sulfate (HS) in the extracellular matrix (ECM) and cell surfaces, and fulfills a significant role in cancer metastasis and angiogenesis. We evaluated the expression of heparanase and its possible association with the expression of angiogenic molecules in malignant mesothelioma (MM), and analyzed whether expression of these proteins is site-related (pleural vs peritoneal MM, solid lesions vs effusions). Sections from 80 MM (56 biopsies, 24 effusions) were analyzed for heparanase protein expression using immunohistochemistry (IHC). Sixty MM were of pleural origin, and 20 were peritoneal. Effusion specimens consisted of 6 peritoneal and 18 pleural effusions, while biopsies consisted of 14 peritoneal and 42 pleural lesions. Fifty-four specimens were additionally evaluated for expression of basic fibroblast growth factor (bFGF), interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF) proteins using IHC. Microvessel density (MVD) was studied in 28 biopsies using an anti-CD31 antibody. mRNA expression of heparanase (HPSE-1), VEGF and the VEGF receptor KDR was analyzed in 23 effusions using RT-PCR. Heparanase protein expression was seen in 69/80 (86%) tumors. Of these, 35 showed combined membrane and cytoplasmic expression, 30 cytoplasmic expression, and four exclusively membrane expression. Both total (P = 0.001) and cytoplasmic (P = 0.002) expression was significantly higher in solid tumors compared to effusions. Protein expression of VEGF, IL-8 and bFGF was seen in 21/54 (39%), 22/54 (41%) and 44/54 (81%) specimens, respectively. Protein expression of bFGF was significantly higher in solid tumors (P < 0.001) and correlated with heparanase expression (P = 0.005). HPSE-1 and VEGF mRNA expression was detected in all 23 effusions using RT-PCR, while KDR mRNA was found in 12/23 MM. KDR mRNA expression correlated with that of both HPSE-1 (P = 0.005) and VEGF (P = 0.001). Our results document frequent expression of heparanase in MM, in agreement with the biological aggressiveness of this tumor. The co-expression of heparanase with bFGF is in agreement with the role of the former in releasing bFGF from the ECM. The concomitant reduction in protein expression of both molecules in effusions as compared to solid tumors, supports the hypothesis of a reduced need for pro-angiogenic stimuli in effusions, and may aid in defining tumor progression in this setting.

Pleural mesothelioma: little evidence, still time to do trials

CONTEXT

The incidence of malignant pleural mesothelioma is increasing throughout most of the world. This cancer is uniformly fatal, and characterised by progressive breathlessness and unremitting pain in the chest wall. From the onset of symptoms, survival is from a few weeks to a few years. Desperation by patients and doctors has driven a search for effective treatments. Clinical benefits are marginal and evidence of a good quality is lamentably lacking.

STARTING POINT

David Sugarbaker is the world's leading proponent of extrapleural pneumonectomy (EPP), an operation in which all the pleura is removed with the lung, pericardium, and diaphragm. He has recently reported the complications of this radical surgery in a series of 496 operations (J Thorac Cardiovasc Surg 2004; 128: 138-46). Although EPP as part of trimodality therapy (preoperative chemotherapy and postoperative radiation) is thought to be the best that can be offered and is regarded as the standard of care for selected patients given the morbidity associated with it, evidence for benefit is needed to justify its wider use. WHERE NEXT? With the increase in the number of cases there is increasing awareness of the disease, leading to earlier diagnosis, and an expectation that something must be done. Survival is short and the treatments on offer are onerous. The only responsible approach from a scientific, compassionate, or economic view (and why not combine all three?) is to find evidence of effectiveness to avoid futile and distressing treatment when possible.

Pleural mesothelioma with cutaneous extension to chest wall scars

BACKGROUND

Cutaneous mesothelioma is rare but may occur following local surgical procedures for visceral mesothelioma or as a metastasis.

METHODS

A patient with pleural mesothelioma, who developed papules within chest wall scars, 14 and 15 months after pleural biopsy and thoracentesis, respectively, is reported.

RESULTS

Histopathology showed an epithelioid tumor forming tubulopapillary and glandular structures. The diagnosis of mesothelioma was confirmed with immunohistochemistry. Tumor cells stained characteristically for low-molecular-weight cytokeratins 5/6, calretinin, and vimentin and were negative for mucicarmine, carcinoembryonic antigen, thyroid transcription factor 1, prostate-specific antigen, gross cystic disease fluid protein, S-100, factor VIII, and CD31.

CONCLUSIONS

Histologically, mesothelioma may resemble a primary adnexal neoplasm, metastatic adenocarcinoma, or angiosarcoma. Immunohistochemistry can clarify the diagnosis. Clinicians should be aware of the varied presentations of mesothelioma, as cutaneous presentations are becoming increasingly common.

Diffuse malignant mesothelioma of the peritoneum and pleura, analysis of markers

Diffuse malignant mesothelioma of the peritoneum is a rare diagnosis. Despite many histopathologic similarities between peritoneal and pleural tumors, clinical and prognostic features may be quite different. There is a paucity of data evaluating molecular features of peritoneal mesotheliomas. Therefore, we compared the results of a battery of immunohistochemical markers, some with therapeutic implications, in patients with primary peritoneal or pleural mesotheliomas. We examined 24 peritoneal and nine pleural malignant mesotheliomas with a battery of immunohistochemical markers (cytokeratin AE1/3, calretinin, c-kit/CD117, desmin, epidermal growth factor receptor (EGFR), estrogen receptors (ER), progesterone receptors (PR), MIB-1, and cleaved caspase-3) in an attempt to distinguish any differences in this tumor arising in these two distinct locations. The results indicate that the only marker to show a significant difference in its staining pattern between these two sites was EGFR (P=0.0004). In all, 92% (22/24) of peritoneal tumors demonstrated 3+ or 4+ immunoreactivity with EGFR, opposed to only 33% (3/9) pleural tumors. There was no significant difference in immunoreactivity between the pleural and peritoneal tumors with c-kit, ER, PR, cleaved caspase 3, calretinin, and desmin. There was a trend toward increased cytokeratin (P=0.07) and MIB-1 (P=0.08) expression in the peritoneal group. There was no significant difference in age, sex, or histologic subtype between the two locations. In conclusion, despite similarities between peritoneal and pleural mesothelioma, there are differences between this neoplasm arising in these two sites. The EGFR expression is more pronounced in peritoneal tumors compared to pleural tumors. The increased expression of EGFR in the peritoneal lesions may be of clinical significance with the recent emergence of epidermal growth factor receptor-targeted therapies.

Extensive palliative surgery for advanced mesothelioma of the tunica vaginalis

Malignant mesothelioma of the tunica vaginalis is a rare tumor managed principally by radical surgical resection. Chemotherapy and radiotherapy have limited efficacy. We report on a 67-year-old man with severe debilitation from multiple scrotal and inguinal recurrences of a malignant mesothelioma originating in the right tunica vaginalis. Local pain from extensive tumor spread prevented ambulation. Aggressive surgical debridement (total penectomy and scrotectomy) and perineal urethrostomy afforded the patient significant improvement in his quality of life before he finally died of the disease 3 years after diagnosis.