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In the WHO classification, pleural tumours of mesothelial and mesenchymal origin as well as lymphoproliferative disorders are distinguished, with malignant mesotheliomas forming the most common primary pleural tumour. Histologically, a prognostically relevant differentiation between epitheloid (40-60 %), sarcomatoid (20-30 %), and biphasic mesotheliomas (20-30 %) is made. Besides other rare primary tumours of the pleura, the differential diagnoses of malignant mesotheliomas comprise carcinomatous pleuritis of intra- and extrapulmonary malignancies. Especially in early tumour stages, the differentiation from reactive pleural changes requires a close interdisciplinary cooperation with a careful correlation between histopathological findings and clinical presentation.

In a case of a 67-year-old man with two different early stages of a predominantly epithelioid mesothelioma ("mesothelioma in situ", "early-stage mesothelioma"), chromosomal imbalances were determined by comparative genomic hybridisation (CGH), a molecular cytogenetic technique to detect chromosomal gains and losses in tumour cells. In the case of the mesothelioma in situ cells, nine different chromosomal alterations could be detected (losses on 3p, 5q, 6q, 8p, 9p, 15q, 22q, Y; gain on 7q), whereas the early-stage mesothelioma showed the same defects except for the gain on 7q. The simultaneous losses of 6q, 9p and 22q, as well as other chromosomal regions, correlate well with the most common defects previously found in 90 cases of more-advanced-stage mesotheliomas using CGH. These data demonstrate that initial chromosomal defects in early stages of mesotheliomas can be detected by conventional CGH in combination with laser microdissection. The molecular cytogenetic findings support the histological diagnosis of a pleural mesothelioma. The surprisingly high number and extent of genomic alterations found in the examined case probably reflects the genomic instability in the tumour cells and indicates a "genetic chaos" even in earlier stages of malignant mesotheliomas.

The incidence of malignant mesotheliomas in Germany has increased since about the mid 1980s, and a further increase is expected until about 2020 due to the peak in asbestos processing in Germany between 1965 and 1980. About 90% of the mesotheliomas recorded in the files of the German Mesothelioma Registry in Bochum are asbestos-related and therefore possibly due to an occupational exposure. In 2003, 717 mesotheliomas were newly diagnosed at the German Mesothelioma Registry. Mesotheliomas are very heterogeneous in terms of histological appearances and of prognosis. At present, the diagnostic gold standard is conventional histology in combination with additional immunohistochemical analysis. We were not able to confirm a promising report that described telomerase reverse transcriptase catalytic subunit (TERT) for the differentiation between reactive and neoplastic mesothelial lesions, which can be extremely difficult. DNA cytometric analysis may also help differentiate between reactive and neoplastic mesothelial lesions. There are some characteristic patterns of chromosomal imbalances as detectable by comparative genomic hybridization (CGH), but at present, specific chromosomal or genetic defects that give rise to a mesothelioma are not known. A reliable pathological diagnosis is the basis for therapeutic, prognostic, and medicolegal consequences. In general, it can be achieved by thoracoscopic inspection with specifically directed biopsy. Furthermore, a description of the peculiarities of each mesothelioma by the pathologist might be the key to a more individual therapy in the future.

Fourteen primary human malignant mesothelioma (HMM) samples obtained from 14 patients were screened for point mutations and microdeletions/microinsertions in exons 1-16 of the chromosome 22q-located tumour suppressor gene neurofibromin 2 (nf2) by single strand conformation polymorphism (SSCP) analysis. In one tumour (7%) a 10 basepair microdeletion of exon 10 was detected by SSCP and subsequently characterised in detail by sequencing. Deletion of the second nf2 allele in laser-microdissected regions of the 10 bp mutation-harbouring tumour was demonstrated by denaturing gradient gel electrophoresis (DGGE) analysis. Simultaneous comparative genomic hybridisation (CGH) analysis also showed losses at chromosome 22q. Our data indicate that functional loss of the NF2 protein may be involved in the formation of a subset of HMMs.

It is established that subtypes of human malignant mesotheliomas (MM) are associated with different survival times. Ninety cases of MM were examined using DNA cytometry and comparative genomic hybridization (CGH), with emphasis on the main histological subtypes; epithelioid, sarcomatoid and biphasic. A comparison by DNA cytometry revealed moderate differences, with the rare subgroup of mesodermomas having the highest and the sarcomatoid group the lowest rate of aneuploidy. Using CGH, 6.2 chromosomal imbalances per case on average could be detected. Losses (4.1/case) were more common than gains of chromosomal material (2.1/case). MM show no single, specific defect, but a typical pattern of genomic defects can be attributed to this tumour entity. Common losses are clustered at the chromosomal regions 9p21 (34%), 22q (32%), 4q31-32 (29%), 4p12-13 (25%), 14q12-24 (23%), 1p21 (21%), 13q13-14 (19%), 3p21, 6q22, 10p13-pter and 17p12-pter (16% each). Common gains are located on 8q22-23 (18%), 1q23/1q32 (16%), 7p14-15 and 15q22-25 (14% each). While differences in the frequencies of the defects between epithelioid and sarcomatoid MM are not as pronounced as are seen with the pleomorphic mesodermomas, several chromosomal locations (3p, 7q, 15q, 17p) show significant variations. The most pronounced distinguishing feature of sarcomatoid MM is a more than fourfold higher number of amplicons. These data indicate that MM has a distinctive tumour biology with a broad spectrum of heterogeneity, as reflected in morphology and also, more subtly, in the patterns of chromosomal imbalances of the subtypes., (Copyright 2002 John Wiley & Sons, Ltd.)

A 31-year-old man presented with malignant peritoneal mesothelioma. His past medical history was uneventful, specifically there was no personal or environmental asbestos exposure. The patient was treated by complete tumor resection including peritonectomy. Because of the histologic diagnosis of a low malignant, unusual highly differentiated epithelioid tumor with very low proliferative activity a postoperative chemotherapy was not administered. After a follow-up of 20 months, the patient is in excellent clinical condition and there is no evidence of disease by computed tomography. The present paper reports a case of this rare variant of malignant peritoneal mesothelioma.

In patients suffering from a variety of severe diseases the detection of erythroblasts in peripheral blood is associated with poor prognosis. However, as yet the prognostic significance of erythroblasts in the blood of patients after cardiothoracic surgery has not been assessed. In a retrospective study we analyzed the database of 2074 patients, of whom 87 died in hospital during the postoperative period. All patients underwent cardiothoracic surgery using a heart-lung machine. Together with erythroblasts in blood, age, sex, body mass index, preoperative ejection fraction, smoking, diabetes mellitus, type of operation, emergency surgery, renal deficiency, pulmonary hypertension, and endocarditis were considered. The postoperative mortality of patients with erythroblasts in peripheral blood (n=57) was 45.6% (n=26), being significantly higher (p<0.001) than the mortality of patients without erythroblasts (3.0%). None of six patients with more than 2000 erythroblasts x 10(6)/l survived. The postoperative detection of erythroblasts is highly predictive of death, the odds ratio after adjustment for the other known prognostic factors being 7.2 (95% confidence interval 3.4-15.1). Erythroblasts were detected for the first time on average 11 +/- 2 days (median: 7 days; n=57) after surgery and 8 +/- 2 days (median: 6 days; n=26) before death. The detection of erythroblasts in blood after cardiothoracic surgery has a high prognostic significance in terms of in-hospital mortality, helping physicians to identify patients at high risk of death. This finding has to be confirmed by a prospective study with the use of a more sensitive and reliable technology and prospectively defined time intervals for counting blood cells.

Solitary fibrous tumours (SFTs) are rare and usually benign neoplasms of mesenchymal origin that are often found in the visceral pleura (fibrous pleural tumour, FPT) or other serosal surfaces. They have also been found in soft tissues. We report the case of an SFT localised in the thigh of an 86-year-old woman. The tumour specimen was examined morphologically, immunohistochemically and molecular genetically, using comparative genomic hybridisation (CGH). The latter detects unbalanced chromosomal alterations in human neoplasms by competitive nucleic acid hybridisation and consecutive computer image analysis. The tumour consists of fibroblast-like cells, arranged in a typical "patternless pattern". Immunohistochemically, the tumour stained positively for vimentin, CD34, CD99, and focally for actin and desmin. No reaction occurred with keratin or S100 protein antibodies. CGH detected a single loss on chromosome 13q.

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.

The aim of the radical resection of lung tumors is curative treatment. However, in each lung tumor of more than 2 cm in diameter an angioinvasion of tumor cells could be proved by morphological means. Frequently, the existence of lymph nodes and especially hematogenic dissemination is underestimated at the time of resection. By pathological-anatomical means in 33% of T1/T2-N2 and 60% of T1/T2-N3 lung tumors, disseminated tumor cells or organoid metastasis in the bone marrow can be demonstrated. Therefore, the demand for radicalness of the surgeon does not agree with a curative tumor therapy in more advanced tumor stages. Actually, the course of the disease following a local radical resection is predominantly predetermined by the individual hematogenic metastatic spread.

Diagnostics, histogenetic derivatives and determination of the mediastinal neoplasms can still be problematic today despite the use of CT and MRT. Although the exact location and determination of neoplasmic density help to reduce the differential diagnostic spectrum in some cases, in the case of a 50-year old patient it was only via thoracoscopy and the taking of specimens that the diagnosis of a bilateral paravertebral crescent-shaped tumour of the posterior mediastinum as a rare myelolipoma could be obtained. Formal and causal pathogenesis of myelopomas are referred to in this paper with special reference to the clinical and pathologico-anatomical findings.