Pseudomesotheliomatous carcinoma of the lung. An immunohistochemical and ultrastructural study of three cases

Fatal hemothorax caused by pseudomesotheliomatous carcinoma of the lung

We present a case of a poorly differentiated pseudomesotheliomatous carcinoma originating in the lung, which was manifested with the distinctly rare complication of massive true hemothorax and persistent blood loss that proved rapidly fatal in spite of surgery. Pseudomesotheliomatous carcinoma of the lung and neoplasia-associated hemothorax are reviewed and discussed.

Pseudomesotheliomatous Lung Carcinoma of Poorly Differentiated Large Cell Type: A case report and review of the literature

A 46-year-old female presented with a 20-day history of right pleuritic chest pain and progressive shortness of breath. She was found to have a right pleural based malignancy initially thought to be a malignant mesothelioma but staining with the mesothelioma tumor markers calretinin, HBME-1 and CK5/6, was negative. Some epithelial markers were positive and microscopically it was consistent with a poorly differentiated large-cell carcinoma. The case was diagnosed as a pseudomesotheliomatous lung carcinoma of poorly differentiated large-cell type.

Tobacco manufacturers' defence against plaintiffs' claims of cancer causation: throwing mud at the wall and hoping some of it will stick

BACKGROUND

In the late 1990s and the early part of this decade, the major US cigarette manufacturers admitted, to varying degrees, that smoking causes cancer and other diseases.

OBJECTIVE

To examine how tobacco manufacturers have defended themselves against charges that their products caused cancer in plaintiffs in 34 personal injury lawsuits, all but one of which were litigated between the years 1986 and 2003.

METHODS

Defence opening and closing statements, trial testimony, and depositions for these cases were obtained from the Tobacco Deposition and Trial Testimony Archive (http://tobaccodocuments.org/datta/). All available defence-related transcripts from these cases were reviewed and a content analysis was conducted to identify common themes in the defendants' arguments.

RESULTS

After review of the transcripts, defendants' arguments were grouped into seven categories: (1) there is no scientific proof that cigarette smoking causes lung cancer; (2) the plaintiff did not have lung cancer as claimed; (3) the plaintiff had a type of lung cancer not associated with cigarette smoking; (4) the plaintiff had cancer that may have been associated with cigarette smoking or smokeless tobacco use, but tobacco products were not to blame in this particular case; (5) the plaintiff had cancer that may have been associated with cigarette smoking, but the defendant's cigarette brands were not to blame; (6) the defendant's cigarettes (or smokeless tobacco) may have played a role in the plaintiff's illness/death, but other risk factors were present that negate or mitigate the defendant's responsibility; and (7) the defendant's cigarettes may have been a factor in the plaintiff's illness/death, but the plaintiff knew of the health risks and exercised free will in choosing to smoke and declining to quit. Use of the argument that smoking is not a proven cause of lung cancer declined in frequency during and after the period when tobacco companies began to publicly admit that smoking causes disease. Corresponding increases occurred over time in the use of other arguments (namely, presence of other risk factors and "free will").

CONCLUSIONS

Despite the vast body of literature showing that cigarette smoking causes cancer, and despite tobacco companies' recent admissions that smoking causes cancer, defendants used numerous arguments in these cases to deny that their products had caused cancer in plaintiffs. The cigarette companies, through their public admissions and courtroom arguments, seem to be saying, "Yes, smoking causes lung cancer, but not in people who sue us".

Pseudomesotheliomatous carcinoma of the lung with a distinct morphology, immunohistochemistry, and comparative genomic hybridization profile

We report 4 cases of pseudomesotheliomatous carcinoma of the lung, which has clinical and microscopic features similar to malignant mesothelioma, but with ultrastructural, immunohistochemical, and molecular characteristics suggestive of a histogenesis from type II pneumocytes. Neoplasm grows as a diffuse or solid pattern of large polygonal cells with sharply defined borders. Hale's colloidal iron is positive in the cytoplasm of small groups of cells and, focally, in some intercellular spaces. Ultrastructure showed short microvilli in the surface. Immunohistochemically, tumor cells were positive for thyroid transcription factor-1, podoplanin, mesothelin, pan-cytokeratin, CK-7, CK-19, Ber-EP4, epithelial membrane antigen, apoprotein surfactant A, epidermal growth factor receptor, Leu-M1, carcinoembryonic antigen, E-cadherin, and CD-44 and negative for mesothelioma markers thrombomodulin and calretinin. In some areas, there were small cysts which contained a concentric fibrilar basophilic material apoprotein surfactant A positive. Chromosomal imbalances with comparative genomic hybridization technique were identified with a median of 15 abnormalities per case (range, 1-26): 51 gains, 6 losses, and 1 high-level amplification. The most frequent aberrations among the cases were gains on chromosomes regions 1q, 3q, 5p, 8q, 16p, and 18q and losses in 17p11-13 and 17q 22-q25. High-level amplifications were detected on 7p13-p21. In all cases, there was a characteristic association between the gains on 16p and those on 18q. The 4 cases resulted in death in less than 14 months, in spite of complete surgery and chemotherapy in 2 cases. Our aim is to complement the current understanding of this pseudomesotheliomatous "pneumocytic" carcinoma and alert pathologists to this rare entity to avoid misdiagnosis.

Systemic sclerosis and pseudomesotheliomatous adenocarcinoma of the lung

A 55-year-old man, diagnosed with systemic sclerosis (SSc) for 20 years, was admitted to our hospital for exertional dyspnea and pleural effusion. Computed tomography scan and cytological findings of the pleural fluid suggested malignant mesothelioma. In the postmortem examination, the tumor was pathologically diagnosed as pseudomesotheliomatous adenocarcinoma (PMA) of the lung, classified into pleomorphic carcinoma with adenocarcinoma component according to the new World Health Organization guidelines. This is the first case report of SSc with PMA.

Synchronous diffuse malignant mesothelioma and carcinomas in asbestos-exposed individuals

AIMS

The development of synchronous diffuse malignant mesothelioma and carcinoma in individuals exposed to asbestos is rare. We report nine cases and discuss the medico-legal implications.

METHODS AND RESULTS

Five hundred patients seeking compensation for asbestos-related diffuse malignant mesothelioma were reviewed with access to post-mortem data. The study group comprised cases in which a second (non-mesothelial) neoplasm was identified. The study group comprised eight males, one female, mean age 68 years (range 60-75). All individuals gave a history of asbestos exposure. Synchronous malignant mesothelioma with carcinoma was identified in 9/500 (1.8%). Eight malignant mesotheliomas were pleural, one was primary peritoneal in origin. By morphological subtyping there were four epithelioid, three biphasic and two sarcomatoid mesotheliomas. In 6/9 (67%) the second tumour was a primary bronchogenic carcinoma (three adenocarcinomas, two squamous cell carcinomas and one small-cell carcinoma). In 3/9 (33%) the second tumour was a non-bronchogenic carcinoma (colonic, pancreatic and breast ductal adenocarcinoma). No other neoplasms were identified in the cohort of malignant mesotheliomas studied. Five persons had pathological evidence of asbestosis (four had bronchogenic carcinomas, one colorectal adenocarcinoma). Two persons with non-bronchogenic carcinomas had identifiable asbestos bodies but no interstitial fibrosis. In two cases the second neoplasms (primary bronchogenic squamous cell and small-cell carcinomas) were associated with diffuse interstitial fibrosis but no asbestos bodies were seen on light microscopy. In each case transmission electron microscopic mineral analysis revealed an asbestos fibre burden within the background population range for control subjects and well below that seen in cases of established asbestosis. These cases were considered to represent cryptogenic fibrosing alveolitis in subjects with a history of asbestos exposure.

CONCLUSIONS

Synchronous malignant mesothelioma with carcinomas in asbestos-exposed workers is rare and identified in 1.8% of 500 malignant mesotheliomas in this series. In most cases the carcinoma represents a primary bronchogenic neoplasm. Primary lung carcinomas are recognized to be asbestos related only when occurring in association with asbestosis. In this series this combination (bronchogenic carcinoma and asbestosis) was seen in four (0.8%) cases. In post-mortem cases for possible malignant mesothelioma it is important to identify any other neoplasia and determine whether it is related to asbestos. Their presence impact upon anticipated life expectancy and in the presence of malignant mesothelioma will affect the compensation settlement.

Pseudomesotheliomatous adenocarcinoma of the lung with rhabdoid features

Pseudomesotheliomatous adenocarcinoma of the lung is a rare entity, clinically and pathologically mimicking diffuse malignant pleural mesothelioma. We report a case of pseudomesotheliomatous adenocarcinoma consisting of two distinct histopathologic components with marked differences in morphological appearance and immunohistochemical staining pattern: a small subpleural nodule consisting of adenocarcinoma and undifferentiated carcinoma with rhabdoid features, the latter extending to the visceral pleura in a diffuse mesothelioma-like growth pattern. The adenocarcinomatous component showed strong reactivity with various epithelial markers, but no reactivity with vimentin. The undifferentiated component showed strong reactivity for vimentin, but no reactivity for epithelial markers. Both components showed no reactivity with CEA, Ber Ep4, MOC-31, B72.3, cytokeratin 5/6, calretinin and thrombomodulin. Metastatic lesions in the duodenum and the periumbilical skin consisted entirely of undifferentiated carcinoma with rhabdoid features. Fluorescence in situ hybridisation (FISH) was performed for chromosomes 4, 7, 20, and 22. FISH results showed polysomy 7 in both components. The diagnosis of pseudomesotheliomatous adenocarcinoma in this case was based on the finding of the subpleural nodule. We conclude that in cases of undifferentiated malignant pleural tumors with cells of rhabdoid phenotype, the possibility of peripheral pulmonary adenocarcinoma dedifferentiating into a more aggressive phenotype should be considered.

Pseudomesotheliomatous carcinoma involving pleura and peritoneum: A clinicopathologic and immunohistochemical study of three cases

Pseudomesotheliomatous carcinoma is a rare variant of peripheral adenocarcinoma of the lung that can manifest clinical, radiologic, and pathologic features similar to malignant mesothelioma. We present three patients with pseudomesotheliomatous carcinoma of the lung. In one patient the carcinoma extended beyond the thorax and extensively involved the peritoneum, mesentery, omentum, and intestines. All patients experienced weight loss and chest pain. All were white men aged 63, 65, and 67 years. Two were smokers and had shortness of breath, cough, and pleural effusion. One had a history of asbestos exposure. No patient developed dyspnea or hemoptysis. One was successfully treated for prostatic carcinoma 18 months earlier. Radiographically, all tumors were pleura-based. Grossly, the tumors spread extensively over pleural (and in one case peritoneal) surfaces and mimicked malignant mesothelioma. Histologically, all tumors were poorly differentiated and necrotic; two tumors exhibited spindle-cell components and desmoplasia. Mucin production was detectable in none, 10%, and 50% of tumor cells. The percentages of tumor cells immunoreactive for Ber-EP4 were 70%, 100%, and 80%; for Leu MI 0%, 90%, and 50%; for epithelial membrane antigen 80%, 80%, and 100%; for B 72.3%, 0%, 90%, and 20%; for polyclonal carcinoembryonic antigen 0%, 10%, and 10%; and for monoclonal 5%, 0%, and 0%. Of these, Ber-EP4 and B 72.3 rendered the most reliable diagnostic results. The clinical, radiologic, and gross and routine histologic findings were similar to those of a malignant mesothelioma; the final diagnosis could be made based mainly on immunocytochemical results. We have reviewed the English and German literature regarding 65 such tumors and present our experience with three additional cases. We emphasize the application of immunocytochemical studies on pleura-based poorly or undifferentiated malignant tumors of unknown origin.

Adenocarcinoma simulating mesothelioma: a clinicopathologic and immunohistochemical study of 29 cases

We report 29 cases of adenocarcinomas whose clinical, gross, and microscopic appearance resembled diffuse malignant pleural mesothelioma. Initial criteria for inclusion in the study included availability of an open pleural biopsy or decortication specimen and microscopic evidence of neutral (periodic acid-Schiff positive) mucin in the tumor. The median age of the patients was 63 years (range, 31 to 78 years), with a peak age in the seventh decade. There were 24 men and five women. Thirteen of them had a history of smoking; six (21%) had possible or definite occupational exposure to asbestos. Three (21%) of 14 lung specimens showed ferruginous bodies and two (14%) showed microscopic evidence of asbestosis. At least 25 patients had pleural effusion, most typically unilateral. Needle biopsy of pleura showed malignancy in 10 (77%) of 13 cases. Most (20 of 29) patients underwent pleural stripping. Radiotherapy and chemotherapy was each given to three patients without effect. Median survival by Kaplan-Meier estimate was 8 months, with an 18-month survival of 13%. Histologically, glands (23 cases), nests (13 cases), tubulopapillary arrays (12 cases), or sheets (eight cases) of tumor cells were found. Spindling of neoplastic cells was seen in 10% of cases. Three (21%) of 14 lung specimens showed a subpleural adenocarcinoma. Antibodies to polyclonal CEA, Ber-EP4, Leu-M1, and B72.3 were positive in 94%, 56%, 50%, and 44% of cases, respectively. All but one of the cases stained with two or more of the antibodies CEA, Ber-EP4, Leu-M1, or B72.3. This study indicates that adenocarcinomas simulating mesothelioma are aggressive variants of peripheral adenocarcinomas with a poor prognosis, that they can show pathological evidence of asbestos exposure in a subset of cases, and that immunohistochemical and histochemical stains are useful in their differential diagnosis with diffuse malignant mesotheliomas.

Papillary serous carcinoma of the peritoneum in a man: a case report

BACKGROUND

Papillary serous carcinoma of the peritoneum (PSCP) is a rare primary peritoneal tumor, described exclusively in women. It is believed to arise from the secondary müllerian system, which is comprised of the pelvic and lower abdominal mesothelial lining and subjacent (subcoelomic) mesenchyme in women. Both mesotheliomas and PSCP arise from the coelomic epithelium, but are clinicopathologically and biologically distinct entities.

METHODS

The authors report clinicopathologic findings in a man, age 74 years, who died 3 months after the diagnosis of an extensive malignant abdominal disease.

RESULTS

The routine histologic and immunocytochemical studies of tumor tissue, obtained during the patient's lifetime and at autopsy, validated the unique occurrence of PSCP in a man.

CONCLUSIONS

This case illustrates that PSCP can occur in a man and that this diagnosis may be considered in the differential diagnosis of papillary serous tumors of the peritoneum in male patients. Although rare, PSCP is a diagnostically distinct entity the treatment of which is similar to ovarian serous tumors rather than mesotheliomas.

Utility of HBME-1 immunostaining in serous effusions

HBME-1 is an anti-mesothelial cell monoclonal antibody derived from human mesothelioma cells. We investigated 227 body cavity effusions to test its utility in differentiating mesothelioma from adenocarcinoma. HBME-1 outlined cell membranes in non-neoplastic mesothelial cells. Thick surface staining was observed on all mesotheliomas. HBME-1 reactivity was also detected in 24% of metastatic carcinomatous effusions. Most ovarian carcinomas (83%) reacted with this antibody, showing surface staining. Cytoplasmic HBME-1 immunoreactivity was observed in a small proportion of non-ovarian adenocarcinomas (14%). Despite its limited specificity, HBME-1 might be added to the battery of other markers of epithelial and/or mesothelial differentiation to be used in cases of suspected mesothelioma. Evaluation of suspicious cells should include careful study of the pattern of immunostaining.

Malignant vascular tumors of the serous membranes mimicking mesothelioma. A report of 14 cases

Malignant endothelial neoplasms involving the serous membranes are rare, and only a few cases have been documented. We report 14 patients with epithelioid hemangioendothelioma (EHE) or epithelioid angiosarcoma (EA) diffusely involving the pleural, peritoneal, or pericardial cavities, resulting in a picture closely resembling mesothelioma. The mean age at diagnosis was 52 (range, 34-85). The patients included two women and one man with peritoneal tumors, eight men with pleural tumors, and three men with pericardial tumors. A shared histological appearance was a diffuse sheet-like and clustered pattern of tumor growth with variable degrees of vascular differentiation. A tubulopapillary growth pattern, often seen in mesothelioma, was prominent in four cases. Nine cases showed a variable number of spindle cells, some neoplastic, others reactive, focally producing a biphasic growth pattern, further suggesting mesothelioma. Initial interpretations included mesothelioma, adenocarcinoma, and, in one case with prominent spindle-cell components, leiomyosarcoma. Immunohistochemically, strong vimentin staining and negative or weak to moderate cytokeratin staining were observed in all 14 cases. The tumor cells coexpressed at least two of the four endothelial markers used in the study (CD31, CD34, von Willebrand factor, and Ulex europaeus agglutinin-I [UEA-I)]. Detection of abortive vessel formation was facilitated by staining for collagen type IV. Markers of mesothelial, epithelial, muscular, and neuronal differentiation were all negative in the subset of cases studied. As a control group, 39 mesotheliomas and more than 60 adenocarcinomas of various origins were studied using the same antibody panel. This group revealed strong keratin staining, moderate or negative vimentin staining, and no expression of any of the endothelial-lineage markers, with the exception of positive staining for UEA-I in occasional adenocarcinomas. Clinically, these endothelial tumors were highly aggressive; 12 patients presented with disseminated disease, and most died within months of the initial presentation. These findings indicate that, although uncommon, EHE/EA should be included in the differential diagnosis of serous membrane neoplasms with histological and clinical features of malignant mesothelioma. The diagnosis of an endothelial neoplasm can be suspected by the presence of abortive vessel formation and by the strong expression of vimentin, with absent or low-level expression of cytokeratin. The demonstration of immunoreactivity for two or more endothelial-associated markers is essential in confirming the diagnosis.

The value of immunohistochemistry of pleural biopsy specimens in the differential diagnosis between malignant mesothelioma and metastatic carcinoma

The aim of the present study was to evaluate the aid of immunohistochemistry in the differential diagnosis between pleural malignant mesothelioma (MM) and secondary pleural carcinoma in pleural biopsy specimens. A series of MM (epithelial or biphasic type) (n = 39), and a series of secondary pleural carcinomas (n = 25) were studied with a panel of monoclonal antibodies against Ber-EP4, CEA, and Leu-MI (CD-15). Considering the markers one, two or three at a time, computer analysis was conducted to identify the immunophenotype with the highest sensitivity and specificity for both MM (n = 39) and adenocarcinoma (n = 19). The CEA/CD-15 marker combination had the highest specificity (MM = 100%; adenocarcinoma = 82.1%), and sensitivity (MM = 82.1%; adenocarcinoma = 100%) considering both categories of tumours. Positive reaction for CEA and/or CD-15 was the best indicator of metastatic adenocarcinoma. Negative reaction for CEA/CD-15 and Ber-EP4/CD-15 showed up to be 100% specific for MM. Positive reaction for one, two or even all these antigens, however, occurred in nine tumours predetermined as MM according to their gross appearance, and absence of other primary malignancies at autopsy. Ultrastructural examination (n = 7) of these tumours strongly supported the diagnosis in one case, and did by no means exclude the diagnosis MM in the other six cases. Neither did any of the tumours reveal ultrastructural signs of adenomatous differentiation, and they did not express PAS/diastase resistant globules, amylase or surfactant. Anti -Ber-EP4 was the antibody most frequently expressed in MM (n = 8). Until antibodies specific for MM are available, the limitation of immunohistochemistry to solve the diagnosis in all cases of pleural malignant tumours has to be considered.

Mesothelioma-like tumors of the pleura: a review of 72 autopsy cases

The 72 mesothelioma-like tumors of the pleura (MLTP) found among 33 500 autopsy cases collected over more than 30 years are reviewed. MLTP have a worse prognosis than the 106 cases of pleural mesothelioma autopsied in our institutes with regard to survival time and metastatic spread. In MLTP, adenocarcinomas predominate with a wide range of histological and cytological variation and prominent development of connective tissue having its origin in the periphery of the lung. These intrapulmonary primary tumors often fulfill the criteria of pulmonary scar cancer. Etiologically, there is no correlation between the origin of this tumor and smoking or exposure to asbestos. The absence of mucus formation and glandular differentiation, together with the presence of spindle-shaped carcinoma components and strong mesothelial or stroma proliferation, can make the differential diagnosis between this tumor type and mesothelioma difficult. Immunohistological investigations were performed on 11 cases with antibodies against intermediate filament proteins, vascular endothelium, collagen IV, macrophage antigens, carcinoembryonic antigen (CEA), LeuM1, and the antibody BerEP4. Our investigation shows that a battery of several tumor markers, such as antibodies against LeuM1, CEA, and the antibody BerEP4, as well as staining with periodic acid/Schiff/diastase discriminate primary from secondary pleural neoplasms, whilst intermediate filament proteins alone are of little diagnostic value.