This is the first report on cerebral changes in eight patients who died of paraquat poisoning. These included generalized oedema, haemorrhages (both subependymal and subarachnoid), glial reactions (microglial activity and astrocytic response) and meningeal inflammation. Oedema and haemorrhage were the most consistent and significant findings; they suggest that paraquat may damage the cerebral blood vessels. The distribution of haemorrhages was unusual and resembled that seen in thiamine deficiency.

SUMMARY One hundred and one testicular tumours previously diagnosed as 'teratoma' were examined and 93 of the patients were followed up. These neoplasms were assigned to one of three groups. Those composed exclusively of somatic tissues were the only tumours referred to as teratoma. The second group was exclusively extra embryonic and consisted of either yolk sac or choriocarcinoma. Neoplasms in the third group were called mixed germ cell tumours and incorporated somatic and extra embryonic tissue and occasionally seminoma. The patients with teratomas showed a very low mortality whereas pure yolk sac tumours proved highly malignant. In mixed germ cell tumours the malignant nature of the yolk sac component was maintained even when combined with somatic elements, but when seminoma was also present the survival rate was significantly improved.It would appear that yolk sac tumour tissue occurs more frequently in adult testicular neoplasms than was previously suspected and in mixed germ cell tumours it can be expected to dictate behaviour except when combined with seminoma.Within the pleomorphic group of gonadal tumours often referred to as 'teratoma' orthodox methods of histological grading are usually inapplicable. Choriocarcinomatous foci, however, are regarded as prognostically sinister. In a study of ovarian mixed germ cell tumours (solid 'teratoma') we concluded that a tumour pattern, considered to be yolk sac in origin, was an important prognostic guide (Beilby and Parkinson, 1975). Based on these findings and the knowledge that serum alpha-fetoprotein (a product of human yolk sac) (Gitlin and Perricelli, 1970) is raised in patients with testicular 'teratocarcinoma' (Norgaard-Pedersen et al., 1975), we investigated the incidence and relation to prognosis of yolk sac tumour in testicular germ cell neoplasms. Material and methodsOne hundred and one testicular tumours previously reported as 'teratoma' at the Middlesex Hospital between 1923 and 1970 were reviewed. Detailed histories were available in 93 of the 101 patients, all of whom had been treated by surgery and radiotherapy. The survivors were followed up for three to 37 years. Paraffin wax blocks from each primary neoplasm were sectioned and stained with haematoxylin and eosin. The tumours, with the exception of one which was undifferentiated, were assigned to one of the following three groups, and the clinical behaviour of these was compared: 1 teratoma, ie, those neoplasms composed exclusively of mature or immature somatic elements; 2 tumours composed exclusively of extra embryonic tissue, ie, choriocarcinoma or yolk sac tumour. The latter was identified by its characteristic range of merging patterns, including Duval-Schiller bodies, intercommunicating channels lined by flattened epithelium, clear celled reticular and microcystic formations, and acinopapillary structures lined by cuboidal and columnar epithelium (Figs.

The clinical and pathological findings are described in 14 patients who died between 6 hours and 26 days after drinking paraquat. Respiratory failure and delayed pulmonary fibrosis have become the hallmark of this poison, but were not the common mode of death in this series. Toxic myocarditis, renal tubular necrosis and centrilobular liver cell damage were significant factors in the eight deaths which occurred within 5 days of paraquat ingestion. Similar abnormalities plus respiratory failure caused the two deaths which occurred 5 and 6 days after consumption of the poison. Respiratory failure was the sole cause of death in only four patients who died 8 to 26 days after drinking paraquat, although the lungs showed pathological changes in all cases. The patients who died in multisystem failure, with one exception, had drunk larger quantities of paraquat than those who survived for a longer period and died in respiratory failure.

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