Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MESOTHELIOMA”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

The use of histological and immunohistochemical markers to distinguish pleural malignant mesothelioma and in situ mesothelioma from reactive mesothelial hyperplasia and reactive pleural fibrosis.

Distinguishing malignant mesothelioma from reactive mesothelial hyperplasia and reactive fibrosis can be a diagnostic problem in small pleural biopsies, made more difficult by the recent recognition of mesothelioma-in-situ. Antibodies to epithelial membrane antigen (EMA), p53, and bcl-2 have all been advocated for differentiating reactive from neoplastic conditions, but reports are inconsistent. These antibodies have therefore been applied to 31 cases of malignant mesothelioma, 34 cases of reactive pleural disease (20 reactive mesothelial hyperplasia and 14 reactive pleural fibrosis) and four small biopsies that were initially coded as suspicious, from patients who later developed frank mesothelioma. Thirty out of 31 (97 per cent) cases of mesothelioma showed positive nuclear staining for p53, with a higher incidence of positivity in epithelioid than in sarcomatoid elements and 30/31 (97 per cent) showed diffuse linear membrane staining for EMA, again more intense in the epithelioid elements. No mesothelioma was positive for bcl-2. In seven cases that contained both in situ and invasive mesothelioma, the in situ elements showed similar staining patterns to the invasive epithelioid elements. Thirteen out of 20 (65 per cent) cases of reactive mesothelial hyperplasia showed occasional nuclear positivity for p53 and 5/20 (25 per cent) cases showed focal weak membrane staining for EMA. Three out of 14 (21 per cent) cases of reactive pleural fibrosis showed positive nuclear staining for p53 and 6/14 (43 per cent) cases showed focal membrane staining with EMA. No reactive cases stained for bcl-2. All four suspicious cases showed diffuse linear staining with EMA and three showed focal staining for p53. It is concluded that strong diffuse linear staining for EMA is a good marker of malignancy when differentiating epithelioid malignant mesothelioma and mesothelioma-in-situ from reactive mesothelial hyperplasia, although weak focal staining may occur in reactive conditions. Nuclear staining for p53 is also suggestive of epithelioid mesothelioma, but should be regarded as no more than suspicious. The antibodies used in this investigation are less helpful in differentiating sarcomatoid mesothelioma from reactive pleural fibrosis.

Biomarkers, Tumor↗

Mesothelioma-binding antibodies: thrombomodulin, OV 632 and HBME-1 and their use in the diagnosis of malignant mesothelioma.

The aim of this study was to examine the expression of three putative mesothelioma-binding antibodies, thrombomodulin, OV 632 and HBME-1 in 42 malignant mesotheliomas (27 pleural and 15 peritoneal) and 32 pulmonary adenocarcinomas. Evaluation of their use in differentiating between the mesotheliomas and pulmonary adenocarcinomas was assessed. Thrombomodulin was expressed by 22 of 42 (52%) mesotheliomas but was seen in eight of 12 pure epithelial-type mesotheliomas of the pleura and in all four papillary epithelial peritoneal mesotheliomas. For pure epithelial mesotheliomas thrombomodulin was 75% sensitive. Only two of 32 pulmonary adenocarcinomas were immunoreactive yielding a 94% specificity for thrombomodulin. In comparison, OV 632 and HBME-1 showed 67% and 62% antibody sensitivity, respectively, for malignant mesothelioma but this was accompanied by low specificity (OV 632, 37%; HBME-1, 28%). Both OV 632 and HBME-1 are considered unsuitable for use in differentiating between mesotheliomas and pulmonary adenocarcinomas. We advocate the use of thrombomodulin as a mesothelioma-binding antibody in the standard panel of antibodies used in the evaluation of malignant mesothelioma.

Adenocarcinoma↗

Immunocytochemical characterization of cell lines from human malignant mesothelioma: characterization of human mesothelioma cell lines by immunocytochemistry with a panel of monoclonal antibodies.

A panel of nine monoclonal antibodies was used to characterize human mesothelioma cell lines that we established from human malignant mesothelioma. The antigens detected were cytokeratin, vimentin, epithelial membrane antigen, carcinoembryonic antigen, Leu-M1 (CD15), desmin, factor VIII-related antigen (von Willebrand factor antigen), OV632, and ME1, a specific monoclonal antibody directed against human malignant mesothelioma. The technique used was the alkaline phosphatase anti-alkaline phosphatase method. All 30 cell lines, either epithelial, sarcomatous, or mixed, showed strong reactivity with cytokeratin and vimentin antibodies. None of the cell lines demonstrated any reactivity with carcinoembryonic antigen, Leu-M1, or factor VIII antibodies; moreover, all of 22 cell lines studied were positive for ME1 antibody and 10 of 12 cell lines studied were positive for OV632. Some interesting features were noted: only two of the 30 cell lines presented a weak positive staining with epithelial membrane antigen, and nine of 19 cell lines tested demonstrated a cytoplasmic staining pattern with desmin antibody. These results show that established human mesothelioma cell lines still possess the immunocytochemical characteristics that are basically consistent with the immunohistochemical features described in tumor tissues of malignant mesothelioma. These characteristics can be used to identify the mesothelioma cells grown from human malignant mesothelioma. Hence, the mesothelioma cell lines will provide a useful tool for the investigation of the cell biology of the tumor and the mechanisms of mesothelial cell transformation, as well as the in vitro evaluation of the effects of some drugs in order to develop new therapies for malignant mesothelioma.

Actins↗

Calretinin and other mesothelioma markers in synovial sarcoma: analysis of antigenic similarities and differences with malignant mesothelioma.

Synovial sarcoma (SS) is a mesenchymal neoplasm that typically shows epithelial differentiation. SS commonly metastasizes to lung and pleura, and has also been reported as the primary in these locations. The histologic distinction of SS from mesothelioma may be difficult because of the combination of epithelioid and spindle cells, potentially shared locations, and antigenic expression. In this study the authors examined 103 well-documented SSs including 41 biphasic, 44 monophasic, and 18 poorly differentiated SSs in comparison with 23 epithelioid and seven sarcomatous mesotheliomas. Most biphasic SSs (29 of 41, 71%) had fields or foci of calretinin-positive tumor cells. The spindle cell components were more often positive (55%), whereas 14% of tumors had positive epithelial cells. The monophasic and poorly differentiated SSs commonly had foci of calretinin-positive cells (in 52% and 56% of cases respectively). In comparison, all 23 epithelioid mesotheliomas (EM) were extensively calretinin positive and seven sarcomatoid mesotheliomas were variably calretinin positive. HBME-1 positivity was similarly detected in biphasic SS and EM (100% and 87% respectively). Among the other sarcomas, two of 15 malignant peripheral nerve sheath tumors were focally calretinin positive, whereas 16 epithelioid sarcomas, 20 leiomyosarcomas, 20 gastrointestinal stromal tumors, and 20 angiosarcomas were negative. Biphasic SSs differed from mesotheliomas by their more common BerEp4 positivity (90%) whereas EMs showed focal reactivity in 13% cases. Marked CD15 reactivity was rare in both. Wilms tumor protein-1 (WT1) was not detected in SS, but was present in 12 of 17 EMs. CD141 was rare in SS, limited to spindle cell components, whereas EMs typically showed prominent membrane staining in epithelial cells. Simple epithelial keratins were present in all epithelial cells of biphasic SS and mesothelioma (keratin 7[K7], K19), but were only focal in monophasic and poorly differentiated SS. Biphasic SSs were extensively K14 positive (89% of cases), whereas epithelial and sarcomatoid mesotheliomas typically showed only scattered positive cells. The potentially shared calretinin patterns in SS and mesothelioma require the use of other markers. The discriminating features include extensive BerEp4 positivity, rarity of CD141, and lack of WT1 in SS. Global expression of K7 and K19 in mesotheliomas versus focal expression in monophasic and poorly differentiated SSs, and differential patterns of K14 expression may also be helpful.

Adolescent↗

The immunohistochemical diagnosis of mesothelioma. Differentiation of mesothelioma and lung adenocarcinoma.

Despite numerous histochemical, ultrastructural, and immunohistochemical studies, differentiation between malignant epithelial pleural mesothelioma and adenocarcinoma of the lung remains extremely difficult. Although there is general agreement that immunohistochemical methods can aid in this distinction, some studies have produced conflicting results with some of the proposed markers for mesothelioma. To obtain comparable and reproducible results, 19 unequivocal epithelial mesotheliomas and 23 unequivocal primary lung adenocarcinomas were studied by the avidin-biotin-peroxidase complex method on formalin-fixed, paraffin-embedded tissue specimens. Well-characterized, commercially available antibodies to carcinoembryonic antigen (CEA), a high- and low-molecular-weight keratin, vimentin, epithelial membrane antigen, human milk fat globule, Leu-M1, TAG-72 (identified by monoclonal antibody B72.3), beta 1 pregnancy-specific glycoprotein (SP1), human placental lactogen, secretory component (SC), CA19-9, and S-100 protein were used. Twenty-one adenocarcinomas (91.3%) reacted for CEA, 14 (60.9%) for Leu-M1, 14 (60.9%) for SC, nine (39.1%) for CA19-9, and eight (34.8%) for SP1; no mesotheliomas stained for any of these markers. Nineteen adenocarcinomas (82.6%) and one mesothelioma (5.3%) reacted with B72.3. Adenocarcinomas and mesotheliomas did not significantly vary in reaction to the remaining antibodies. None of the antibodies used was specific for mesothelioma, but CEA was the single most useful marker. One of the two adenocarcinomas negative for CEA was positive for TAG-72, Leu-M1, and SC, and the only B72.3-positive mesothelioma was negative for CEA, Leu-M1, SC, CA19-9, and SP1. These findings indicate that greater sensitivity in differentiating mesothelioma and adenocarcinoma can be achieved by immunostaining for both CEA and one or more of the markers TAG-72 (B72.3), Leu-M1, SC (these three have the highest sensitivity and specificity after CEA), CA19-9, and SP1.

Adenocarcinoma↗

Malignant mesothelioma--German mesothelioma register 1987-1999.

OBJECTIVES: The study group comprised a collective of 1,605 patients with malignant mesotheliomas and with lung tissue available for lung dust analyses. METHOD: Clinical features, occupational histories, expositions and individual data were evaluated, and the asbestos bodies concentrations (asbestos bodies/cm3 lung tissue or g wet tissue) were determined. RESULTS: Mesotheliomas developed mainly in men (94.5%). Of the cases, 96.4% were of pleural origin and only 3.3% were peritoneal mesotheliomas. The biphasic subtype predominated (61.3%), followed by the epithelioid type (29.3%). The sarcomatoid subtype was rarely developed (9.4%). Mean age at first diagnosis was 60.4 years. The mean survival time from time of symptom onset was 13.5 months. Patients with epithelioid subtypes had a longer survival time (16.9 months) than those with biphasic (13.1 months) and sarcomatoid subtypes (5.5 months). Of the patients, 73% presented pleural effusions as initial symptoms of the disease. An increased asbestos burden was identified by light microscopy in 84.8% of the patients. There was no association between histological subtypes and the asbestos burden of the lungs. Patients with peritoneal mesotheliomas had distinctly higher asbestos burdens in the lungs than patients with pleural mesotheliomas. There exists no association between lung asbestos burdens and survival times. The mean latency period was 37.8 years. A trend: higher asbestos burden of the lung/shorter latency periods was suggested. About 70% of the patients had a history of occupational exposure to asbestos dust. Most patients worked in the building trade, the locksmith and machine building industries and in the steel and blast-furnace industries. Of the patients, 25.6% had asbestos-associated lung fibroses, in 40.7% of the cases pleural plaques were identified. CONCLUSIONS: The most important causal factor for development of mesotheliomas is still asbestos, primarily amphibole asbestos. The recurring occurrence of mesotheliomas in younger people without known asbestos exposure needs the urgent investigation of other inducing factors for mesotheliomas.

Adult↗

Malignant pleural mesothelioma: some aspects of epidemiology, differential diagnosis and prognosis. Histological and immunohistochemical evaluation and follow-up of mesotheliomas diagnosed from 1964 to January 1985.

64 diffuse pleural mesotheliomas diagnosed between 1964 and January 1985 at the Institute of Pathology of the University of Freiburg were analyzed. Since 1980 an increase from one case to 10 cases per year has been observed. The tumor was 3 to 4 times more frequent in men than in women. The age distribution showed a peak between the age of 50 and 60. In 26 cases evidence of exposure to asbestos was detected. In one patient radiotherapy of Hodgkin's disease may have been of etiological significance. The median survival time was 13 months. The five-year survival rate was only 4%. Histologic reevaluation was only possible in cases diagnosed after 1975. Of 43 cases thus evaluated 26 were pure mesothelial, 15 biphasic and 2 of the spindle-cell subtype. A median survival time of 23 months for pure mesothelial mesothelioma in comparison to 13 months for the biphasic mesothelioma indicated a better prognosis for pure mesothelial mesothelioma. Although no other primary tumors were detected, in 10 cases the differential diagnosis of adenocarcinoma had to be considered, and in 3 cases tumors of non-epithelial origin had to be excluded. 35 of 43 mesothelioma were CEA-negative, 38 out of 43 cytokeratin-positive, and 33 out of 43 were EMA-positive. Factor-VIII-related antigen was not demonstrated. 12 of 43 mesotheliomas showed PAS-positive staining, 29 of 43 were stained with Alcian blue. 7 of these 29 showed a positive digestion with hyaluronidase. Although CEA may not be negative in every mesothelioma, this marker seems to be a valid tool for the differential diagnosis of adenocarcinoma. In order to safeguard against a mistaken diagnosis of pleural mesothelioma, the exclusion of other tumors is always indispensable.

Adult↗

Reactive mesothelial hyperplasia vs mesothelioma, including mesothelioma in situ: a brief review.

In biopsy tissue, discrimination between reactive mesothelial hyperplasia and epithelial mesothelioma can pose a major problem for the surgical pathologist. Confidence in the diagnosis is often proportional to the amount of tissue available for study and depends largely on findings of invasion and the extent and cytologic atypia of the lesion, because there is no marker specific for the mesothelium and that discriminates consistently among normal, hyperplastic, and neoplastic mesothelial tissue. Therefore, mesothelioma in situ is diagnosable only when invasive epithelial mesothelioma is demonstrable in the same specimen, in a follow-up biopsy specimen, or at autopsy. Comparison of 22 cases of mesothelioma in situ that fulfill these requirements for diagnosis with 141 invasive mesotheliomas and 78 reactive mesothelioses indicates that strong linear membrane-related labeling for epithelial membrane antigen and silver-labeled nucleolar organizer region-positive material that occupies 0.6677 microm2 or more of the nucleus in an atypical in situ mesothelial lesion of the pleura are found consistently in neoplastic mesothelial cells. Although these findings may engender suspicion of mesothelioma in situ in high-risk persons, the criteria for diagnosis of pure mesothelial lesions of this type are still under study. Mesothelioma in situ should be considered proved only when unequivocal invasion is identified in a different area of the pleura or at a different time; a diagnosis of pure mesothelioma in situ should not be made in patients not exposed to asbestos.

Biopsy↗

Pathology of human malignant mesothelioma--preliminary analysis of 1,517 mesothelioma cases.

The author reviewed 1,517 human malignant mesothelioma cases from 1975 through August 2000. These mesothelioma cases were definite or probable in diagnostic certainty. Sources of these cases varied including asbestos insulation workers, UNARCO workers, Cancer and Leukemia B mesothelioma panel cases and random cases. Pathology materials consisted of autopsy, biopsy and rare cytology specimens. 92.3% of these patients were male, and 85.8% were between 50 and 79 years in age. The major primary site of the tumor was the pleura (73.1%). However, in a group of the asbestos insulation workers, the peritoneum was the more common primary site of malignant mesothelioma, compared to the pleura. Histologically, epithelial cell type was the majority (61.1%), followed by biphasic (22.1%) and fibrosarcomatous (16.4%). A double primary tumor (malignant mesothelioma associated with other cancer) was present in 32 of the 1,517 cases. These 32 cancers included lung cancers, renal cell carcinomas, colorectal cancers, pancreatic cancers and a cancer of the larynx, which are known to be at higher risk among asbestos insulation workers. The latency period of the vast majority (98.1%) of these mesothelioma cases were longer than 20 years. It is well accepted that cigarette smoking does not contribute to the induction of malignant mesothelioma. Indeed, the present study confirmed that 19.9% of these mesothelioma patients had never smoked cigarettes.

Adult↗

Trends in mesothelioma incidence and occupational mesotheliomas in Finland in 1960-1995.

OBJECTIVES: The study analyzed the recent trend in the incidence of mesothelioma in Finland and evaluated the coverage of reporting work-related mesothelioma. METHODS: The incidence of mesothelioma in 1960-1995 was retrieved from the Finnish Cancer Registry, and the number of asbestos-associated work-related mesotheliomas were taken from the Finnish Register of Occupational Diseases. RESULTS: The annual number of mesotheliomas increased rapidly in 1975-1990. In the 1990s, the age-adjusted incidence remained relatively stable for Finnish men. The annual number of cases still increased among men over 65 years of age, but decreased slightly among men under 55 years of age and among women. About 35 annual cases were diagnosed among men and 10-15 among women in the mid-1990s. The reporting of work-related mesotheliomas improved during the Finnish asbestos program in 1987-1992. In 1993-1995 about 30 annual cases (ie, about 90% of all pleural and 50% of the peritoneal mesotheliomas in men) were reported to be work-related. CONCLUSIONS: The increasing trend in the incidence of mesothelioma in Finland has slowed down in the 1990s, and the maximum of asbestos-related cases in the early 2000s will probably be clearly less than the 100 annual cases estimated in the early 1990s. If the observed trend continues up to 2010, about 40-50 cases among men and 10-20 among women will then be diagnosed annually. Altogether 40-50 of these cases would be related to occupational asbestos exposure.

Aged↗

Comparative studies of human malignant mesothelioma in vivo, in xenografts in nude mice, and in vitro. Cell origin of malignant mesothelioma.

Several decades ago, it was reported that normal and malignant mesothelial cells were transformed into distinct cell types (epithelial to fibrous and fibrous to epithelial) when transferred to in vitro conditions. Those tissue culture data are still cited as evidence supporting that the mesothelial cell has multipotentiality of differentiation and the mesothelial cell is a sole precursor of malignant mesothelioma cells. Six cell lines of heterotransplanted human malignant mesothelioma in nude mice and one cell line of subcultured human malignant mesothelioma in vitro have been established. To establish the validity of the classic concept of multipotentiality of malignant mesothelioma, we studied malignant mesothelioma cells of the seven cases using in vivo cultures, xenografts in nude mice and an in vitro tissue culture, utilizing histology, histochemistry, immunocytochemistry and electron microscopy. The nature of the original malignant mesothelioma cells was clearly shown to be well preserved in both the heterotransplanted and subcultured cells. Data did not support earlier hypotheses that mesothelial cells are capable of differentiating into distinct cell lines. The mesothelial cell and the submesothelial connective tissue cells are the precursors of the neoplastic cells in malignant mesothelioma.

Aged↗

Immunocytochemistry of malignant mesothelioma: OV632 as a marker of malignant mesothelioma.

In pleural or ascitic effusions the cytomorphological distinction of adenocarcinoma cells, reactive mesothelial cells, and malignant mesothelioma cells often causes a diagnostic dilemma. The value of immunocytochemistry was investigated on cytological smears of 24 well-established cases of malignant mesothelioma, a selected series of 31 metastatic adenocarcinomas, and 20 smears of patients without known malignancy. In these smears we scored the immunoreactivity with a panel of four monoclonal antibodies. In addition to antibodies for epithelial membrane antigen (EMA) and carcinoembryonic antigen (CEA), the monoclonal antibody MOC31 and the ovarian carcinoma specific antibody OV632 were incorporated in the panel. With none of these four antibodies was immunostaining of reactive mesothelial cells found. CEA- and MOC31-positive tumour cells were frequent in metastatic adenocarcinomas, but occurred rarely in malignant mesotheliomas. EMA-positive tumour cells were found in all metastatic adenocarcinomas (100 per cent) and in most malignant mesotheliomas (83 per cent). In addition to the expected reactivity of OV632 with ovarian carcinomas, 22 of 24 malignant mesotheliomas contained immunopositive tumour cells, while only a small proportion of non-ovarian adenocarcinomas reacted with this antibody. This selective staining of malignant mesothelioma cells, but not reactive mesothelial cells, with OV632 now permits the positive identification of malignant mesothelioma cells in male patients.

Adenocarcinoma↗

The frequency of p53 immunostaining in asbestos-associated mesotheliomas and non-asbestos-associated mesotheliomas.

It has been suggested that asbestos might have an important role in the development of p53 mutations in mesotheliomas. The objective of this study was to examine asbestos-associated mesotheliomas and non-asbestos-associated mesotheliomas to establish whether the frequency of p53 immunostaining and, by implication, p53 gene mutation is related to asbestos exposure. Immunopositivity for p53 was found in seven (44%) of the 16 mesotheliomas examined. The frequency was approximately the same in both the asbestos-associated mesotheliomas and the non-asbestos-associated mesotheliomas. It is concluded that the frequency of p53 immunostaining in mesotheliomas and, by implication, the frequency of p53 gene mutation is probably not related to asbestos exposure.

Asbestos↗

Image analysis of mesothelioma. I. differentiation of mesothelioma from adenocarcinoma of the lung.

OBJECTIVE: To explore the usefulness of nuclear micromorphometric analysis for the differentiation between epithelial mesothelioma and metastatic adenocarcinoma in the chest wall. STUDY DESIGN: High-resolution images of 2,100 nuclei from 27 cases of epithelial mesothelioma and 15 cases of adenocarcinoma of the lung were recorded. Stepwise discriminant analysis and a nonparametric classifier were applied to derive estimates for a case diagnosis correct classification rate. RESULTS: Nuclei from epithelial mesothelioma and adenocarcinoma of the lung showed statistically significantly different properties, but there was a region of overlap in feature space such that approximately 15-20% of cases could not be correctly classified. The lesion signatures derived from the mesothelioma cases with discriminant function scores that might result in case misclassification and the cases of adenocarcinoma of the lung spanned a similar range of degree of nuclear abnormality. However, the distribution of nuclear abnormality values for the mesothelioma cases has a mode at 0.87 SD from normal, whereas the distribution seen in lung adenocarcinoma cases had a mode at about 3.7 SD. CONCLUSION: Cases of epithelial mesothelioma and adenocarcinoma of the lung have nuclei with a wide range of deviation from normal in the spatial and statistical distribution of their nuclear chromatin. For approximately 80% of cases, correct case classification can be provided by nuclear micromorphometric analysis. Cases of epithelial mesothelioma with highly abnormal nuclei overlap in feature space with nuclei from adenocarcinoma of the lung. However, it is possible that characterization by a lesion signature may allow correct assignment for those cases.

Adenocarcinoma↗

Malignant mesothelioma: immunohistochemistry and DNA ploidy analysis as methods to differentiate mesothelioma from benign reactive mesothelial cell proliferation and adenocarcinoma in pleural and peritoneal effusions.

OBJECTIVE: To determine whether malignant mesotheliomas can be differentiated from adenocarcinomas and benign reactive mesothelial cells in pleural and peritoneal fluids using immunohistochemical analysis in conjunction with DNA ploidy analysis. DESIGN: Sixteen cases of malignant mesothelioma, including epithelial, sarcomatous, and biphasic types, were collected. DNA analysis using flow cytometry and/or image analysis was performed on paraffin-embedded tissue from 15 of the mesothelioma cases, as well as on cytospin cell preparations from samples of pleural and peritoneal fluids from cases with either cytologically proven adenocarcinoma (seven cases) or benign reactive mesothelial cells (seven cases). Immunohistochemical studies were done in 15 mesotheliomas, 5 adenocarcinomas, and 4 benign reactive mesothelial cell effusions. RESULTS: All malignant mesotheliomas tested (100%) stained positively for prekeratin, whereas stains for carcinoembryonic antigen, B72.3, Leu-M1, and Ber-EP4 were negative. Stains vimentin, epithelial membrane antigen, and CA125 were positive in 75%, 75%, and 25% of cases tested, respectively. Benign reactive mesothelial cell cases stained similarly. Adenocarcinomas were more likely to react positively with B72.3, Ber-EP4, and carcinoembryonic antigen, and negatively with vimentin. DNA analysis showed that all benign cases were diploid, while all adenocarcinomas were nondiploid. Fifty-three percent of the malignant mesotheliomas were nondiploid. Sensitivity for detection of nondiploidy was greater for image analysis than for flow cytometry (100% vs 75%). CONCLUSIONS: B72.3, Ber-EP4, carcinoembryonic antigen, and vimentin are useful immunohistochemical markers in differentiating malignant mesotheliomas from adenocarcinomas, whereas immunohistochemistry does not reliably distinguish malignant from benign hyperplastic mesothelial cells. The addition of DNA ploidy studies is useful for differentiating the latter two groups.

Adenocarcinoma↗

Localized and diffuse mesotheliomas of the genital tract and peritoneum in women. A clinicopathologic study of nineteen true mesothelial neoplasms, other than adenomatoid tumors, multicystic mesotheliomas, and localized fibrous tumors.

Peritoneal mesotheliomas are rare in women, compared to serous epithelial neoplasms with which they are often confused. We evaluated the clinicopathologic features of 19 true mesothelial neoplasms affecting the genital tract or peritoneum of women (other than adenomatoid tumors, benign multicystic mesotheliomas, and localized fibrous tumors) to characterize their clinicopathologic features and to determine their clinical behavior. Six tumors were localized to one anatomic site at presentation, and 13 involved more than one anatomic site. The six localized tumors were solitary, small (0.8-2.0 cm), polypoid or nodular lesions, five of which were incidental findings. All had a predominantly tubulopapillary pattern, either pure or mixed with adenomatoid-like or small solid foci. Nuclear grade ranged from 0 to 2. Mitotic figures (MF) were absent in two tumors. The mitosis count in the other four tumors was < 1 MF/10 high-power microscopic fields (HPF) (average method) and ranged from 1 to 3 MF/10 HPF (highest count method). Five patients were alive without recurrence after postoperative intervals ranging from 19 months to 9 years (median, 5 years); one patient died of metastatic gastric carcinoma at 14 months. Thirteen tumors involved more than one anatomic site and were classified as diffuse mesothelioma. Typically, these tumors were symptomatic and accompanied by ascites. The tumors had either a plaque-like or endophytic configuration. Eleven were purely epithelial mesotheliomas, and two had a minor sarcomatoid component. Tubulopapillary patterns were present in 10 tumors, usually admixed with focal adenomatoid-like or solid patterns, and three had a purely solid pattern. All 13 tumors had grade 3 nuclei. The mitosis count ranged from < 1 to 2 MF/10 HPF (average count method) with a range of 1-4 MF/10 HPF by the highest count method. Immunohistochemically, 13/13 tumors stained for cytokeratin (AE1/AE3). None were immunoreactive for polyclonal carcinoembryonic antigen (CEA), Leu-M1, or B72.3. One diffuse mesothelioma stained focally for Ber-EP4, and electron microscopy confirmed the mesothelial nature of this tumor. Nine patients died of tumor after postoperative intervals ranging from 1 month to 6 years. Eleven patients had received postoperative adjuvant intraperitoneal or systemic chemotherapy. One patient died with increased abdominal girth 8 years after operation and one course of intraperitoneal chemotherapy, though the role of mesothelioma in her death was uncertain. One patient was alive with diffuse tumor and persistent ascites 25 months after six courses of intraperitoneal chemotherapy. One patient was alive without evidence of disease 4 months after two courses of systemic chemotherapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenomatoid Tumor↗

Severe chromosomal aberrations in pleural mesotheliomas with unusual mesodermal features. Comparative genomic hybridization evidence for a mesothelioma subgroup.

Malignant mesotheliomas are tumors known for their extensive heterogeneity. Apart from the three classical patterns, predominantly epithelioid, sarcomatoid, and biphasic, some rare variants do exist. In some cases, one can find uncommon additional mesodermal tumor components. These tumors have previously been called "mesodermomas" and, like regular mesotheliomas, are usually associated with a previous asbestos exposure. We examined eight cases of mesodermomas by light microscopy, immunohistochemistry and comparative genomic hybridization (CGH). Besides biphasic and epithelioid areas, unusual epithelial, chondroid, osseous, or even angioblastic elements may be found to varying degrees. Immunohistochemical analysis shows similar staining results as with regular mesotheliomas. CGH reveals a high number of chromosomal imbalances (16.5 per case; range, 11-27). In 10 classical biphasic mesotheliomas that served as a control, defects of comparable number and severity could not be detected (8 per case; range, 2-16). The most frequent defects of mesodermomas (losses on 1p, 4pq, 9p, 13q, 14q, and gains on 1q and 15q), however, could also be found in mesotheliomas of the classical type. Thus, our results support the classification of the so-called mesodermomas as a separate tumor subgroup while maintaining the relationship to the classical mesotheliomas. Therefore, we propose to use the term mesodermoma for this subgroup.

Aged↗