Ultrastructural observations on the histogenesis of localized fibrous tumours of the pleura (benign mesothehoma)

Summary Five localized fibrous tumours of the pleura (benign mesothelioma) were studied ultrastructurally in order to elucidate their histogenesis. The histological subtypes of this benign fibrous lesion of the visceral pleura, i.e. the cellular, the collagenous, and the hyaline, were separately analysed.The tumours are composed of undifferentiated mesenchymal cells, intermediate and differentiated fibroblasts as well as collagenous interstitial tissue. The varying distribution of these cell elements account for the various histological subtypes. Morphological similarities between the mesenchymal tumour cells and the superficial mesothelial cells, which are always separated from the true tumour tissue by an intact basement membrane, were not observed.The different cellular elements can be regarded as parts of a continuous spectrum of cytodifferentiation, in which the mature fibroblasts are derived via intermediate forms from the undifferentiated cells. It is concluded that the localized fibrous tumours of the pleura arise from immature mesenchymal stem cells, which seems to be normally found in the submesothelial layer of the visceral pleura.     

Classification, histologic and cytologic grading and regression grading of prostate cancer

The submitted recommendation of the pathologic- urologic team "prostatic carcinoma" is the result of several meetings, in order to provide a basis for a uniform nomenclature in diagnosis, therapy, and prognosis of prostatic carcinoma to urologists and pathologists in practice.     

Lactate in fetal tissue during hypoxia; correlation to lactate, pH and base deficit in the fetal blood

It was the aim of this study to investigate the relationship between the tissue concentrations of lactate in different organs, the blood lactate concentrations, and pH and base deficit in the extracellular fluid (BDecf) during fetal hypoxia. With regard to fetal blood analysis during labour the question is of major importance to what extent blood measurements can provide information concerning intracellular lactate concentrations, especially in the cerebral tissue. In 15 guinea-pig fetuses acute hypoxia was induced by anaesthesia, operative stress and abruption of the placenta. After puncture of the umbilical artery for blood analysis, tissue specimens were taken from the cerebral tissue, heart, liver, lung, muscle and fascia of the abdominal wall, bowel and kidney within 1 to 2 minutes and analyzed for lactate. The lactate concentrations were corrected according to the time interval from blood sampling to collection of tissue specimen. In acute hypoxia the lactate concentrations of the heart and the cerebral tissue were closely correlated to lactate, pH and base deficit measured in arterial blood. The tissue concentration of lactate in the heart and in the cerebrum exceeded the blood level approximately by 70 and 30-50%, respectively. At a pH greater than 7.10 and BDecf less than 8 mumol/ml, the lactate concentration in the cerebrum was about half the lactate concentrations leading to cerebral edema and cell necrosis in the hypoxic monkey fetus (Myers RE. In: Gluck L, ed. Intra-uterine asphyxia and the developing fetal brain. 1977, 37-97).     

CT-guided cutting needle biopsies of thoracic lesions in patients with negative bronchoscopic findings

Purpose

The usefulness and the complication rate of CT-guided core biopsies for obtaining specimens for histopathological examinations in patients with uncertain thoracic lesions were evaluated.

Materials and methods

Under local anesthesia CT-guided core biopsies were performed in 121 patients using tru-cut systems (14?C18?gauge). Prior to CT all patients underwent bronchoscopy without obtaining sufficient material for a definite histopathological diagnosis. The following areas were punctured: lungs 84 (69%), pleura, chest-wall, ribs 24 (20%) and mediastinum 13 (11%). The diameter of the punctured lesion averaged 4.3?cm.

Results

Using CT-guided puncture techniques specimens could be obtained in 118 (97.5%) out of 121?patients. Of these 118 specimens 3 (2.5%) showed marked artifacts and necrosis, which obscured a definite histopathological opinion. In the end the biopsies from 115 (95.0%) out of 121 patients could be used whereby 84 (73.0%) were classified as malignant and 31 (27.0%) as benign. Due to further operations or bronchoscopic procedures in 35?patients additional material was obtained for histopathological tests. In 3 (8.6%) of those 35?patients newly malignant disease was diagnosed, therefore these specimens showed a relevant discrepancy as compared to the result of the CT-guided biopsy. Obviously the vital central part of the tumor was not biopsied due to poor delineation caused by peritumoral infiltration. A small pneumothorax or haemoptysis was seen in 17 (14.3%) out of 121?patients.

Conclusions

Despite negative bronchoscopic findings CT-guided core biopsies will deliver sufficient specimens for histopathological tests in 95% of patients with uncertain thoracic lesions. Infiltrations surrounding the vital part of the tumor may obscure the correct targeting and lead to false negative results in a few patients. Severe complications were not seen in this study, although they might happen in rare cases according to reports in the literature. Therefore CT-guided core biopsies represent an efficient and safe procedure in patients with thoracic lesions.