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Patients suffering from pulmonary asbestosis show a high incidence of malignant-tumour formation. Particular attention has been given in the past to the occurrence of carcinoma of the lung. Doll (1955) assessed the average risk among men employed for 20 or more years at one asbestos factory as 10 times that among the general population. More recently a close association has been found to exist between exposure to asbestos and the development of diffuse mesothelioma. Wagner et al. (1960) described 33 examples of diffuse pleural meso thelioma from the North Western Cape Province of South Africa. All but one of the patients had been exposed to asbestos and many had worked in the local asbestos mines. Later, Wagner (1962) described 75 cases of diffuse pleural meso thelioma together with three examples of diffuse peritoneal mesothelioma. Occupational or environmental exposure to asbestos had occurred in all but two of the patients. In the present investigation a study has been made of 17 examples of diffuse mesothelioma occurring in the Merseyside area. In each case evidence has been sought of exposure to asbestos dust.

The prevalence of pleural and pulmonary abnormalities attributed to asbestos among 15,000 workers in a naval dockyard has been studied by means of a one-in-ten sample. Ninety-four per cent. of the men in the sample were examined. Of these, 3% had experienced continuous occupational exposure to asbestos and half of the remainder (representing approximately 6,800 men) had been exposed intermittently. The prevalence of pleural fibrosis ranged from 28% in continuously exposed workers to 1.9% in those with least exposure.Most cases of pulmonary fibrosis occurred in laggers and sprayers who had been continuously exposed for between 15 and 20 years. Pulmonary fibrosis was also seen in a variety of intermittently exposed trades, and had been preceded by extensive pleural thickening in some cases. Ten cases of pleural mesothelioma have occurred in the last three years and a large number of men appear to be potentially at risk.

In a retrospective study of the incidence of mesothelioma in Scotland for 1950-67 80 cases were traced from pathological reports and biopsy material of malignant tumours invading the pleura and peritoneum. These cases were matched with two sets of controls. Detailed histories of residence, occupation, and degree of exposure to asbestos confirmed that the incidence of mesothelioma in Scotland is similar to that in other parts of Britain.

In Muenster in 1957 [1], I presented a paper entitled “A preliminary experimental assessment of the significance of asbestos bodies”. I stated in the paper that following Fahr’s [2] first observation of peculiar bodies in sections from the lung of a patient dying of asbestosis, there had been considerable controversy concerning the composition of these bodies and the role that they play in the pathogenesis of the disease.

To the Editor:— May I comment on the excellent paper by Maxwell Borow et al which appeared inThe Journal( 201 :587, 1967)? On page 591 they quote me as stating that I produced experimental mesotheliomas with three types of asbestos, and also with silica. This appeared in the preliminary paper ( Nature 196 :180,1962). Further experiments were undertaken which were mentioned in New York ( Ann NY Acad Sci 132 :505, and not 77-86, as quoted by the authors of the paper). In this paper I explained that we had confirmed the previous results with the three types of asbestos, but were doubtful if the silica tumors were in fact mesotheliomas. In a further paper given at Perugia 1 I described the silica tumors in detail and concluded that they were not mesotheliomas, but definitely reticulum cell sarcomata. This view has since been confirmed by Dr. A. H. T. Robb-Smith.

Greenberg, M., and Lloyd Davies, T. A. (1974).British Journal of Industrial Medicine,31, 91-104. Mesothelioma Register 1967-68. A register of mesothelioma cases is maintained by the Department of Employment, Medical Services Division (now Employment Medical Advisory Service). This paper describes an investigation of 413 notifications to the Register in 1967-68 from England and Wales and Scotland. Cases were regarded as `definite9 when histological confirmation of diagnosis had been obtained, either by hospital pathologists, or by the UICC Panel of Pathologists, to whom pathological material was submitted whenever possible. Two hundred and forty-six cases were accepted as `definite9 and 76 cases were regarded as `definitely not9 mesothelioma. The remainder were classified as `undecided9 or `insufficient pathological material9. Thirty-five of the 76 cases definitely not mesothelioma had nevertheless been so described on death certificates. The investigation carried out covers clinical aspects, survival, and evidence of exposure to asbestos. Twelve per cent of definite mesotheliomata were of peritoneal origin. The age range was 21 to 87 years, but, in general, mesothelioma occured at an earlier age than `carcinoma of bronchus and lung9 or `all malignant tumours9 in the Registrar General9s statistical mortality tables. Concomitant asbestosis and the finding of asbestos bodies or pleural plaques occured as frequently in those cases classified as definitely not mesothelioma as in confirmed cases. Occupational exposure to asbestos was found in 68% of definite cases, apparently significantly more frequently than in those definitely not mesothelioma, but there was observer bias. The interval between the first exposure and death from mesothelioma exceeded 25 years in 85% of cases but was only three and a half years in one case. The duration of exposure varied widely: in 12% of cases it was under five years. The type of asbestos could be ascertained in so few cases that it was impossible to asses the role of crocidolite in aetiology. There were 38 definite cases in which no history of any exposure to asbestos could be obtained. Definite mesotheliomata showed marked clustering in areas where there is substantial industrial use of asbestos. Whether this should be interpreted as evidence of causation or an effect of heightened awareness in these areas cannot be deduced from this study. Evidence is quoted suggesting that the observed annual incidence of approximately 120 definite mesotheliomata in England, Scotland, and Wales may considerably understate the true prevalence.

Statistical and clinical studies were carried out in 1443 patients with tumors of reticuloendothelial system (RES) and 2188 patients with tumors of lymphoid tissue treated between 1953 and 1962 at universities and other hospitals in Japan. It is noteworthy that the incidence of lymphoid reticulum cell sarcoma is high in Japan. However, the incidence of tumors of RES and lymphoid tissue is still lower than that in most of other countries. As to the age distribution there was a significant difference between Japan and other countries, and it has been suggested that the incidence of lymphoid reticulum cell sarcoma in over 55 years of age was actually increasing. There were some differ-ences in frequency of initial symptom, presenting symptoms and signs between tumors of RES except lymphoid reticulum cell sarcoma and lymphoid tissue. The characteristic hematologic findings have not been observed at the initial phase of tumors of RES and lymphoid tissue. Also in this paper pathophysiology, effects of therapies and survival time of patients with tumors of RES and lymphoid tissue have been reported.

ALTHOUGH excellent accounts have been published in recent years of the gross and histological pathology of neoplasms believed to be diffuse malignant mesotheliomas, there remains a scarcity of adequate descriptions of their exfoliative cytology. One purpose of this paper is to help correct this deficiency. Another is to present further evidence that diffuse malignant mesothelioma really exists, for undoubtedly there are still some who are not convinced that there is such an entity.

The present study deals with 11 malignant tumors arising from the spermatic cord. Ten of the tumors were of mesoblastic origin and one was a teratoma. Local recurrence appeared to be a common problem and was attributed to inadequate removal of the primary tumor at biopsy. Distant metastasis occurred only in the late stages of disease after local recurrence could not be controlled or when retroperitoneal disease had become extensive. Radical orchiectomy followed by retroperitoneal node dissection was considered the treatment of choice for this disease. ETWEEN THE YEARS 1931 AND 1966, 24 PAB tients with tumors of the testicular adnexa were seen at the Memorial and James Ewing Hospitals. Of these, 13 arose in the spermatic cord, 7 in the epididymis, 2 from the tunica albuginea and 1 each from the rete testis and an adrenal rest, respectively. Of particular interest were those cases which were histologically malignant, since many of these had presented with primary intrascrotal swellings often confused with testicular tumor. In addition, these tumors constituted an uncommon group of neoplasms for which the clinical course and prognosis had not been clearly defined.l.11, 21, 34 The present paper deals specifically with the spermatic cord tumors considered to be histologically malignant. Experience with the other adnexal lesions will be described sep

This paper describes techniques used in tracing and obtaining cooperation from relatives in a retrospective study in Scotland. The purpose of the study was to investigate the associations between the development of mesothelioma and exposure to asbestos dust. From the information obtained from relatives, it was possible to show that, compared with controls, patients who died of mesothelioma had a significantly greater occupational exposure to asbestos.

I would like to make a few comments and pose a question or two concerning the question of the lymphohematogenous spread of asbestos. The paper by Godwin and Jagatic (1) is one of the more important publications that I have come across concerning the distribution of fibers in patients in whom there was both asbestosis and mesothelioma. This study was done very carefully and demonstrated rather nicely the presence of fibers in various organs throughout the body including the spleen and lymph nodes, hilar lymph nodes particularly. Another study with of considerable interest is by Kanazawa et al. (2). They injected crocidolite subcutaneously in rats and found the regional lymph nodes to be rather heavily involved by these fibers. The fact that these fibers apparently can cross various natural barriers such as the endothelial wall and the gastric, small intestinal, and even colonic epithelium seems to be fairly well shown. This raises several very interesting questions. Those of us who have had an opportunity over the years to look at the gastric and intestinal mucosa are very impressed by the dynamic nature of this epithelial surface. The epithelial surface of the gastro intestinal tract is a highly dynamic structure, the cells changing shape and size continuously. The renewal rate varies somewhat, but is in the range of 2-5 days. So when you have a very dynamic situation all sorts of things can happen, including the insorption of relatively large particles, which you would not ordinarily predict from the static

Primary neoplasms of the pleura are among the very rare tumors. They occur considerably less frequently than primary growths of the lung or bronchi. Clinically and pathologically the malignant tumors of the pleura form the most interesting and important group. The pathogenesis and consequently the nomenclature of these tumors is still in confusion. Wagner,1in 1870, described the classical pleural tumor under the name "tuberkelaehnliche lymphadenome," which opened a long controversy. Schultz,2in 1875, reexamined the preparations of Wagner and gave a complete description of the above tumor, emphasizing the neoplastic nature of the growth and naming it "endothelial cancer." These two papers mark the beginning of a stubborn contention which, fifty years after its inception, still remains unsettled. Among the other designations which have been used to describe malignant pleural tumors may be mentioned: lymphangitis proliferans (Fraenkel, Schweninger); lymphangitis carcinomatodes (Neelson); sarcocarcinoma (Boehme), alveolar endothelial sarcoma (Podak), endothelioma (Eppinger