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The diagnosis of lung cancer in coal-miners with pneumoconiosis
Brit. 07. Dis. Chest (x965) 59, t4 I.
THE DIAGNOSIS OF LUNG CANCER IN COALMINERS WITH PNEUMOCONIOSIS BY K. P . GOLDMAN* SullyHospital,Sully,Glamorgan THE clinical and radiological manifestations of lung cancer in coal-miners may be indistinguishable from those of pneumoconiosis. In particular there is often difficulty in distinguishing a tumour in the periphery of the lung from progressive massive fibrosis (P.M.F.). This may lead either to delay in the diagnosis and treatment of a cancer or to an unnecessary thoracotomy for a non-malignant lesion. Several authors have described cases in which massive fibrosis was thought to be lung cancer, with subsequent discovery of the error at operation or at autopsy (Lovelock, 1939; Bradshaw and Chodoff, 1939; Rendich and Camiel, 1943; Davies and Snow, 1958; Smith, 1959; Kujawski, Myslak and Kossmann, I96o ). By contrast, others have described how the presence of lung cancer may be masked by coincidental pneumoconiosis (Gernez-Rieux et al., i96Ia), so that the tumour may escape detection until death. For example, out of 12 South Wales coal-miners who were found at autopsy to have both lung cancer and P.M.F., in only 2 had the tumour been diagnosed before death (James, 1955). T h e object of this paper is to illustrate some of the points which give rise to difficulties in diagnosis and to discuss criteria for distinguishing lung cancer from coal-workers' pneumoconiosis. The illustrative case reports refer to miners from South Wales, where the incidence of P.M.F. is especially high (Cochrane, Cox, and J a r m a n , 1952 ).
Case Reports T h e first four cases illustrate the diagnostic problems presented by miners with solitary lesions in the periphery of the lung. The fifth case is about the investigation of a miner with pneumoconiosis and atelectasis. Co.$ei
E. R. was a coal-miner aged 62 who was referred for investigation following an acute febrile illness and right chest pain. He had worked underground for 25 years and smoked 20 cigarettes daily for most of his life. Examination revealed a healthy-looking man, with a mild generalized wheeze but no other abnormal physical signs. T h e chest X-ray (Fig. I) showed category 2 simple pneumoconiosis, a small, indistinct shadow in the first left intercostal space, suggesting early P.M.F., and * Present address: Brompton Hospital, London • (Receivedfor publication, February 1965 .)
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a large, dense, oval-shaped shadow in the right upper lobe which was seen on the lateral view to be placed posteriorly. No previous chest X-rays were available for comparison. Bronchoscopic appearances were normal, and a bronchogram showed incomplete peripheral filling of the posterior segment, right upper lobe. The diagnosis was uncertain, and because the patient complained of persistent chest pain and was losing weight it was decided to operate. A thoracotomy was performed and the main lesion was located in the right upper lobe posteriorly, but a biopsy which was sent for frozen section showed the typical histology of massive fibrosis with no evidence of carcinoma. When last seen, four years after operation, the man was well and the main lesion appeared unchanged. In retrospect it would seem that the shadow on this X-ray was unusually clearly outlined for P.M.F. The persistent chest pain favoured the diagnosis of a malignant lesion, although this symptom is not uncommon among miners with massive fibrosis. Case 2 G. P., aged 52, had worked underground for 20 years, but in I945 pneumoconiosis was diagnosed and he left the mines. He was admitted to hospital in 1959 complaining of fever, loss of weight, and pain in the right side of the chest. Examination revealed a thin, ill-looking man; there was clubbing of the fingers and signs of a contracted right upper lobe. The other systems were normal. The chest X-ray (Fig. 2) showed category 2 simple pneumoconiosis, shadows suggesting early P.M.F. in the left upper zone, and a large, dense shadow in the right mid zone. Bronchoscopy was performed which showed a tumour at the orifice of the right upper lobe bronchus, and the histology was that of an oat cell carcinoma. At thoracotomy a tumour was found at the hilum of the right lung which involved all three lobes, and a right pneumonectomy was performed. The pathologist reported that the main part of the tumour was embedded in an area of massive fibrosis and coal-dust. In this case the appearance of the tumour on the chest X-ray had been modified by surrounding pneumoconiosis. The correct diagnosis was suggested by the rapid onset of symptoms and by the presence of finger-clubbing, both these features being more characteristic of lung cancer than of P.M.F. Case 3 H. A. had worked as a gold-miner in Brazil and subsequently as a coalminer in South Wales. He was admitted to hospital at the age of 65 for investigation of a recent ha:moptysis. There had been a chronic productive cough and moderate dyspnoea after exertion for the previous 8 years. He smoked 2o cigarettes daily. O n admission he appeared wasted and ill and there were signs of consolidation over the fight upper lobe. The chest X-ray (Fig. 3) showed category 3 simple pneumoconiosis, and a large, ill-defined shadow in the right mid zone; the mediastinum was slightly displaced to the right. Lateral tomograms showed the lesion to be mainly
T I I E D I A G N O S I S OF L U N G C A N C E R IN C O A L - M I N E R S W I T H
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posterior, and there was a suggestion of central cavitation. Bronchoscopic appearances were normal and no malignant cells or tubercle bacilli were seen in the sputum. Lung cancer could not be excluded clinically and a thoracotomy was performed, at which a large, hard mass was felt in the apex of the right lower lobe, with spread to the upper lobe. The hilar glands were also enlarged and hard. A pneumonectomy was performed for apparent carcinoma. However, although the pathologist reported a dense mass of fibrosis and dust and one area offibrocaseous tuberculosis, there was no evidence of a carcinoma. The resected lymph glands were anthracotic, not malignant. A review of the X-ray in this case shows that in comparison with that of case 2 the shadow was less clearly outlined and less dense, and points slightly in favour of P.M.F. rather than cancer. However, there is no evidence of massive fibrosis in the opposite lung, which is misleading because P.M.F. (except in the early stages) usually involves both lungs. Case 4 D. W. R. was a coal-miner aged 34 who had worked underground for 19 years. He was admitted to hospital complaining of a productive cough for the past 3 months and general malaise for the same period. He had also noticed pains in the knees and shoulders for 6 weeks. He had been a heavy cigarettesmoker for m a n y years. At the time of admission he appeared fairly healthy and no abnormal physical signs were detected. The chest X-ray showed (Fig. 4) category i simple pneumoconiosis, a small opacity in the first left intercostal space, and a larger opacity in the right lower zone. No tubercle bacilli or malignant cells were seen in the sputum and bronchoscopic appearances were normal. A bronchogram showed a normal bronchial tree, except that there was incomplete filling of contrast medium in the apical segment, right lower lobe. The provisional diagnosis was tuberculosis, and chemotherapy was given as an out-patient while the results of sputum cultures were awaited. However, the cultures were reported to be negative; and during the course of the next few months, despite continued chemotherapy, the lesion in the right lower lobe was observed to enlarge. This suggested that a neoplasm might be present, although the shadow on the X-ray seemed unusually ill-defined for a carcinoma. The patient was re-admitted to hospital and a right thoracotomy was performed. The lesion was located deep in the lower lobe and the surgeon proceeded to lobectomy. The pathologist reported that the mass consisted of an aggregation of small nodules which had the characteristic histology of Caplan's syndrome. Several isolated nodules were also found in the periphery of the lobe. There was no evidence of carcinoma or tuberculosis. Despite the history of arthralgia in this patient, Caplan's syndrome could not reasonably have been diagnosed before operation. The X-ray appearance was highly atypical compared with the classical presentation, namely of multiple, well-defined, circular opacities in both lung-fields. The one clue was the
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small, round shadow in the left upper lobe, which is fairly typical of that seen in the early stages of this condition. Case 5 A. G. W. had worked underground as a coal-miner for 2o years. He was admitted to hospital at the age of 49, complaining of a productive cough for the past 6 months and difficulty in swallowing for 6 weeks, the food seeming to stick at the mid-sternal level. On examination there were no abnormal physical signs. The chest X-rays (Figs. 5 and 6) showed partial atelectasis of the right middle lobe and a background of category 3 simple pneumoconiosis. Bronchoscopic appearances were normal, and at oesophagoscopy a mass was felt behind the posterior wall of the oesophagus 22 cm. from the mouth. The latter finding was confirmed by a barium swallow examination, which showed a filling defect in the middle third of the oesophagus. It seemed that an enlarged gland, probably malignant, was exerting pressure on the middle lobe bronchus and oesophagus. At thoracotomy partial atelectasis of the middle lobe was confirmed. Several enlarged, hard lymph glands were seen at the hilum of the lung and one such gland was adherent to the middle lobe bronchus and the oesophagus. This gland was partially resected, and histological examination showed fibrosis and coal-dust, but there was no evidence of tuberculosis or carcinoma. When last seen, 5 years later, the patient still noticed mild dysphagia but was otherwise well. This case was unusual, for although the regional lymph glands are commonly affected in both simple and complicated coal-workers' pneumoconiosis, they rarely exert significant pressure on neighbouring structures. Discussion
The clinical distinction between lung cancer and P.M.F. is uncertain, for many symptoms are common to both diseases. Thus cough, dyspnoea, h~emoptysis, chest pain, and loss of weight can all be caused by either malignant or pneumoconiotic lesions. In general P.M.F. produces no symptoms in the early stages, but this is equally true of tumours in the periphery of the lung. The onset and progression of symptoms, particularly dyspnoea, is more gradual in P.M.F. than in cancer, and characteristically the dyspnoea may be quite severe without there being any other symptoms. The main radiographic problem is to distinguish P.M.F. from a peripheral carcinoma, and in such cases bronchoscopy is rarely helpful. Of great importance is the presence of simple pneumoconiosis, for its absence virtually excludes the diagnosis of P.M.F. (Fletcher, 1955; Cochrane and Miall, 1956). However, there have been two reports of massive fibrosis occurring in the absence of any radiographic sign of simple pneumoconiosis, and in each case a thoracotomy was performed because the lesion was thought to be a carcinoma (Davies and Snow, I958; Smith, i959) , two cases of exceptional rarity. The location of a peripheral lesion is often of diagnostic importance, for,
PLATE I I I
FIG. l.--Simple pneumoconiosis. Early P.M.F. in the left upper lobe, and a large, dense shadow in the right upper lobe.
FIG. 2.--Simple pneumoconiosis. Early P.M.F. in the left upper lobe, and a dense shadow extending from the right hilum to the periphery of the lung.
FIG. 3.--Simple pneumoconiosis and a dense, ill-defined shadow in the right mid-zone.
FIG. 4.--N[inimal simple pneumoconiosis. A small opacity at the periphery of the first left intercostal space, and a large, ill-defined opacity at the periphery of the right lower' zone.
To face p. 244.
P L A T E IV
FIG. 5.--Simple pneumoconiosis. Early P.M.F. in both upper lobes and partial atelectasis of the right middle lobe.
FIG. 6.--Right lateral view showing partial
atelectasis of the middle lobe.
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whereas a tumour can arise in any part of the lung, P.M.F. usually arises in the upper part, in either an upper lobe or the apex of a lower lobe. Thus a solitary lesion in a basal segment is more likely to be cancer, in which respect case 3 was exceptional. A large opacity in any part of one lung-field, in the absence of other opacities, is unlikely to be caused by P.M.F., which (except in its early stages) is usually bilateral, and in this respect also case 3 was unusual. The shape, size, and density of an X-ray shadow are of little help in distinguishing lung cancer from P.M.F., but the latter is generally less clearly outlined. This difference is not applicable if the tumour is located in an area of massive fibrosis, as it was in case 2. The most reliable guide to the patholog-y of a pulmonary lesion is its rate of growth as seen on serial X-rays. The growth rate of P.M.F. is comparatively slow and only appreciable on the X-ray over a period of several years, whereas the growth of lung cancer is more rapid and can be appreciated over a period of months or even weeks. There are exceptions, and rarely a small tumour remains radiographically unchanged for months or years before entering a phase of rapid expansion (Simon, I962 ) . The rate of growth can only be assessed if previous films are available for comparison--which they often are for miners, if all possible sources are searched, including the Coal Board, the Ministry of Pensions and the M.M.R. A peripheral pulmonary lesion in Caplan's syndrome may be mistaken for lung cancer (case 4)- The typical case, with rheumatoid arthritis and multiple circular shadows on the X-ray, presents no problem. Diagnosis is more difficult if there is a solitary pulmonary lesion (case 4), or if the appearance of the X-ray shadow precedes the onset of arthritis. The rate of growth of a pulmonary rheumatoid nodule is comparable to that of a malignant lesion, and in such a case the occurrence ofjoint symptoms might be mistaken for hypertrophic osteoarthropathy. Although the lesions of massive fibrosis are typically solid, on occasion they excavate due to ischmmic necrosis or concomitant tuberculosis (Kdlpatrick, Heppleston, and Fletcher, 1954). The appearances on the X-ray, namely of a thick-walled abscess, often resemble those of a cavitating carcinoma of the lung. In such cases the clinical history should help to distinguish between the two, for excavation in P.M.F. is preceded by melanoptysis, or the expectoration of sputum blackened with coal-dust. The sputum should also be examined for malignant cells and tubercle bacilli. Bronchography can be a useful aid to differential diagnosis. A peripheral carcinoma usually occludes the bronchus proximal to it, the filling defect on the bronchogram being either abrupt or of the " r a t tail" variety, and at a later stage there is evidence of occlusion of the surrounding bronchioli (Molmar and Rieble, I963). By contrast, in P.M.F. the bronchographic appearances are essentially of bronchial distortion rather than occlusion. A personal review of 15 bronchograms in cases of complicated pneumoconiosis showed that irregularity of the small bronchi and displacement towards areas of massive fibrosis were the commonest abnormalities, and in three cases there was bronchiectasis associated with concomitant tuberculosis. In only one bronchogram was there an abrupt
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filling defect of a segmental bronchus in relation to massive fibrosis which might have been mistaken for carcinoma. Similar bronchographic appearances to these in P.M.F. have been reported by Rosmanith and Bruckner (1958) and by Gernez-Rieux and colleagues (i 961 b), who described the essential changes as those o f " bronchitis deformans". Although most of this discussion has been confined to the diagnosis of peripheral tumours, lung cancer more commonly arises in one of the main bronchi. Here it may cause pneumonia or atelectasis, and produce a segmental or lobar X-ray shadow of a type rarely seen in pneumoconiosis. Case 5 is an exception, in which an enlarged anthracotic gland exerted pressure on the middle lobe bronchus and on the oesophagus, causing atelectasis and dysphagia. Middle lobe atelectasis has also been reported by Ellis (I964) in five coalminers and a foundry worker with simple pneumoconiosis; active tuberculosis was confirmed in four of them. The author considered the condition was secondary to active or healed tuberculous endobronchitis, perhaps following invasion by an adjacent tuberculous lymph node, although enlarged glands were evident in only one of his patients. Atelectasis has also been described as a complication of enlarged pulmonary lymph glands in classical silicosis (Kergin, 1952 ; Paul, I96I ). Inevitably cases arise in which the diagnosis of a pulmonary lesion cannot be achieved without a thoracotomy. However, even after inspection and palpation of a lesion the surgeon may still be unable to distinguish between lung cancer and massive fibrosis or between malignant and anthracotic lymph glands, so closely can they resemble each other. This situation sometimes results in a pulmonary resection for what is later found to be a pneumoconiotic lesion (case 3). This type of error is particularly liable to occur if the patient is an ex-miner and the relevant occupational history has not been elicited. I f there has been a thorough clinical and radiological assessment before operation the surgeon will be aware of the possibilities and if necessary will take a biopsy for frozen section before proceeding to pulmonary resection.
Summary The diagnosis of lung cancer in men who have worked in coal-mines is complicated by the clinical and radiographic similarities of malignant and pneumoconiotic lesions. Cases are reported which illustrate some of the problems, namely the similarity between peripheral lung cancer and coalworkers' massive fibrosis, between lung cancer and Caplan's syndrome, and between bronchial obstruction caused by a tumour and by an anthracotic lymph gland. Criteria for distinction between the two types of lesion are discussed, and bronchography as an aid to differential diagnosis is referred to. ACKNOWLEDGEMENTS I wish to thank Dr. H. M. Foreman, Dr. L. R. West, Mr. D. M. E. Thomas, and Mr. H. R. S. Harley for permission to write about patients who were under their care at Sully Hospital. I am most grateful to Dr. L. R. West for advice about the interpretation of bronchograms. Mr. F. Midgley prepared the photographic illustrations.
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REFERENCES BRADSHAW,H. H., & CI-XODOFF,R . J . (1939). Amer. Rev. Tuberc., 39, 817COCHRANE,A. L., Cox, J. G., & JARMAN,T. F. (1952). Brit. med. 07., 2, 843. COCHRANE,A. L., & MIALL, W. E. (I956). Brit. reed. 07., x, I I93. DAVIES, W. C., & SNOW, W. T. (I958). 07. thorac. Surg., 36, x85. ELLIS, R. H. (i 964). Brit. 07. Dis. Chest, 58, 169. FLETCHER, C. M. (I955). A.M.A. Arch. industr. Hlth, xI, 17. GERNEZ-RI~ux, CH., VOISIN, C., BALGAIRES,E., DELEPOULLE, E., & LENOIR, L. (I96Ia). Lille mgd., 6, 551 . GERNEZ-RIEUX, CH.,
~¢[ARCHAND, IVY.,M O U N I E R - K u H N ,
P.,POLICARD, A., & ROCHE, L. (1961b).
In Broncho-Pneumopathies professionnelles. Paris: Masson. p. 3 19" JAMES, W. R. L. (I955). Brit. 07. industr. Med., I2, 8 7. I~ROIN, F. G. (I952). 07. thorac. Surg., 24, 545. KXLPATRmK,G. S., HEPPLESTON,A. G., & FLETCheR, C. M. (I954). Thorax, 9, 260. KUJAWSKA,A., 1V[YSLAK,Z., & KOSSMANN,S. (I96o). Pol. Tyg. lek., x5, 825. LOVBLOCK,J. E. (i939). Brit. reed. 07., 2, 8. MOLNAR, W., & RI~.BEL, F. A. (I963). Radiologic Clinics of N. America, I, 3%. PAUL, R. (I96I). Arch. environm. Hlth, 2, 9 6. RENDICH, R. A., & CAM!F.L,M. R. (I943). 07. thorac. Surg., x2, 686. ROSMANITH,J., • BRUCKNER,L. (I958). 07. thorac. Surg., x2, 686. SIMON,G. (I962) . In Principles of Chest X-ray Diagnosis, 2nd edition. London: Butterworth. p. 6 9. S~IT~, R. A. (I959). Brit. 07. industr. Med., x6, 318.
THE DIAGNOSIS OF LUNG CANCER IN COALMINERS WITH PNEUMOCONIOSIS BY K. P . GOLDMAN* SullyHospital,Sully,Glamorgan THE clinical and radiological manifestations of lung cancer in coal-miners may be indistinguishable from those of pneumoconiosis. In particular there is often difficulty in distinguishing a tumour in the periphery of the lung from progressive massive fibrosis (P.M.F.). This may lead either to delay in the diagnosis and treatment of a cancer or to an unnecessary thoracotomy for a non-malignant lesion. Several authors have described cases in which massive fibrosis was thought to be lung cancer, with subsequent discovery of the error at operation or at autopsy (Lovelock, 1939; Bradshaw and Chodoff, 1939; Rendich and Camiel, 1943; Davies and Snow, 1958; Smith, 1959; Kujawski, Myslak and Kossmann, I96o ). By contrast, others have described how the presence of lung cancer may be masked by coincidental pneumoconiosis (Gernez-Rieux et al., i96Ia), so that the tumour may escape detection until death. For example, out of 12 South Wales coal-miners who were found at autopsy to have both lung cancer and P.M.F., in only 2 had the tumour been diagnosed before death (James, 1955). T h e object of this paper is to illustrate some of the points which give rise to difficulties in diagnosis and to discuss criteria for distinguishing lung cancer from coal-workers' pneumoconiosis. The illustrative case reports refer to miners from South Wales, where the incidence of P.M.F. is especially high (Cochrane, Cox, and J a r m a n , 1952 ).
Case Reports T h e first four cases illustrate the diagnostic problems presented by miners with solitary lesions in the periphery of the lung. The fifth case is about the investigation of a miner with pneumoconiosis and atelectasis. Co.$ei
E. R. was a coal-miner aged 62 who was referred for investigation following an acute febrile illness and right chest pain. He had worked underground for 25 years and smoked 20 cigarettes daily for most of his life. Examination revealed a healthy-looking man, with a mild generalized wheeze but no other abnormal physical signs. T h e chest X-ray (Fig. I) showed category 2 simple pneumoconiosis, a small, indistinct shadow in the first left intercostal space, suggesting early P.M.F., and * Present address: Brompton Hospital, London • (Receivedfor publication, February 1965 .)
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a large, dense, oval-shaped shadow in the right upper lobe which was seen on the lateral view to be placed posteriorly. No previous chest X-rays were available for comparison. Bronchoscopic appearances were normal, and a bronchogram showed incomplete peripheral filling of the posterior segment, right upper lobe. The diagnosis was uncertain, and because the patient complained of persistent chest pain and was losing weight it was decided to operate. A thoracotomy was performed and the main lesion was located in the right upper lobe posteriorly, but a biopsy which was sent for frozen section showed the typical histology of massive fibrosis with no evidence of carcinoma. When last seen, four years after operation, the man was well and the main lesion appeared unchanged. In retrospect it would seem that the shadow on this X-ray was unusually clearly outlined for P.M.F. The persistent chest pain favoured the diagnosis of a malignant lesion, although this symptom is not uncommon among miners with massive fibrosis. Case 2 G. P., aged 52, had worked underground for 20 years, but in I945 pneumoconiosis was diagnosed and he left the mines. He was admitted to hospital in 1959 complaining of fever, loss of weight, and pain in the right side of the chest. Examination revealed a thin, ill-looking man; there was clubbing of the fingers and signs of a contracted right upper lobe. The other systems were normal. The chest X-ray (Fig. 2) showed category 2 simple pneumoconiosis, shadows suggesting early P.M.F. in the left upper zone, and a large, dense shadow in the right mid zone. Bronchoscopy was performed which showed a tumour at the orifice of the right upper lobe bronchus, and the histology was that of an oat cell carcinoma. At thoracotomy a tumour was found at the hilum of the right lung which involved all three lobes, and a right pneumonectomy was performed. The pathologist reported that the main part of the tumour was embedded in an area of massive fibrosis and coal-dust. In this case the appearance of the tumour on the chest X-ray had been modified by surrounding pneumoconiosis. The correct diagnosis was suggested by the rapid onset of symptoms and by the presence of finger-clubbing, both these features being more characteristic of lung cancer than of P.M.F. Case 3 H. A. had worked as a gold-miner in Brazil and subsequently as a coalminer in South Wales. He was admitted to hospital at the age of 65 for investigation of a recent ha:moptysis. There had been a chronic productive cough and moderate dyspnoea after exertion for the previous 8 years. He smoked 2o cigarettes daily. O n admission he appeared wasted and ill and there were signs of consolidation over the fight upper lobe. The chest X-ray (Fig. 3) showed category 3 simple pneumoconiosis, and a large, ill-defined shadow in the right mid zone; the mediastinum was slightly displaced to the right. Lateral tomograms showed the lesion to be mainly
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posterior, and there was a suggestion of central cavitation. Bronchoscopic appearances were normal and no malignant cells or tubercle bacilli were seen in the sputum. Lung cancer could not be excluded clinically and a thoracotomy was performed, at which a large, hard mass was felt in the apex of the right lower lobe, with spread to the upper lobe. The hilar glands were also enlarged and hard. A pneumonectomy was performed for apparent carcinoma. However, although the pathologist reported a dense mass of fibrosis and dust and one area offibrocaseous tuberculosis, there was no evidence of a carcinoma. The resected lymph glands were anthracotic, not malignant. A review of the X-ray in this case shows that in comparison with that of case 2 the shadow was less clearly outlined and less dense, and points slightly in favour of P.M.F. rather than cancer. However, there is no evidence of massive fibrosis in the opposite lung, which is misleading because P.M.F. (except in the early stages) usually involves both lungs. Case 4 D. W. R. was a coal-miner aged 34 who had worked underground for 19 years. He was admitted to hospital complaining of a productive cough for the past 3 months and general malaise for the same period. He had also noticed pains in the knees and shoulders for 6 weeks. He had been a heavy cigarettesmoker for m a n y years. At the time of admission he appeared fairly healthy and no abnormal physical signs were detected. The chest X-ray showed (Fig. 4) category i simple pneumoconiosis, a small opacity in the first left intercostal space, and a larger opacity in the right lower zone. No tubercle bacilli or malignant cells were seen in the sputum and bronchoscopic appearances were normal. A bronchogram showed a normal bronchial tree, except that there was incomplete filling of contrast medium in the apical segment, right lower lobe. The provisional diagnosis was tuberculosis, and chemotherapy was given as an out-patient while the results of sputum cultures were awaited. However, the cultures were reported to be negative; and during the course of the next few months, despite continued chemotherapy, the lesion in the right lower lobe was observed to enlarge. This suggested that a neoplasm might be present, although the shadow on the X-ray seemed unusually ill-defined for a carcinoma. The patient was re-admitted to hospital and a right thoracotomy was performed. The lesion was located deep in the lower lobe and the surgeon proceeded to lobectomy. The pathologist reported that the mass consisted of an aggregation of small nodules which had the characteristic histology of Caplan's syndrome. Several isolated nodules were also found in the periphery of the lobe. There was no evidence of carcinoma or tuberculosis. Despite the history of arthralgia in this patient, Caplan's syndrome could not reasonably have been diagnosed before operation. The X-ray appearance was highly atypical compared with the classical presentation, namely of multiple, well-defined, circular opacities in both lung-fields. The one clue was the
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small, round shadow in the left upper lobe, which is fairly typical of that seen in the early stages of this condition. Case 5 A. G. W. had worked underground as a coal-miner for 2o years. He was admitted to hospital at the age of 49, complaining of a productive cough for the past 6 months and difficulty in swallowing for 6 weeks, the food seeming to stick at the mid-sternal level. On examination there were no abnormal physical signs. The chest X-rays (Figs. 5 and 6) showed partial atelectasis of the right middle lobe and a background of category 3 simple pneumoconiosis. Bronchoscopic appearances were normal, and at oesophagoscopy a mass was felt behind the posterior wall of the oesophagus 22 cm. from the mouth. The latter finding was confirmed by a barium swallow examination, which showed a filling defect in the middle third of the oesophagus. It seemed that an enlarged gland, probably malignant, was exerting pressure on the middle lobe bronchus and oesophagus. At thoracotomy partial atelectasis of the middle lobe was confirmed. Several enlarged, hard lymph glands were seen at the hilum of the lung and one such gland was adherent to the middle lobe bronchus and the oesophagus. This gland was partially resected, and histological examination showed fibrosis and coal-dust, but there was no evidence of tuberculosis or carcinoma. When last seen, 5 years later, the patient still noticed mild dysphagia but was otherwise well. This case was unusual, for although the regional lymph glands are commonly affected in both simple and complicated coal-workers' pneumoconiosis, they rarely exert significant pressure on neighbouring structures. Discussion
The clinical distinction between lung cancer and P.M.F. is uncertain, for many symptoms are common to both diseases. Thus cough, dyspnoea, h~emoptysis, chest pain, and loss of weight can all be caused by either malignant or pneumoconiotic lesions. In general P.M.F. produces no symptoms in the early stages, but this is equally true of tumours in the periphery of the lung. The onset and progression of symptoms, particularly dyspnoea, is more gradual in P.M.F. than in cancer, and characteristically the dyspnoea may be quite severe without there being any other symptoms. The main radiographic problem is to distinguish P.M.F. from a peripheral carcinoma, and in such cases bronchoscopy is rarely helpful. Of great importance is the presence of simple pneumoconiosis, for its absence virtually excludes the diagnosis of P.M.F. (Fletcher, 1955; Cochrane and Miall, 1956). However, there have been two reports of massive fibrosis occurring in the absence of any radiographic sign of simple pneumoconiosis, and in each case a thoracotomy was performed because the lesion was thought to be a carcinoma (Davies and Snow, I958; Smith, i959) , two cases of exceptional rarity. The location of a peripheral lesion is often of diagnostic importance, for,
PLATE I I I
FIG. l.--Simple pneumoconiosis. Early P.M.F. in the left upper lobe, and a large, dense shadow in the right upper lobe.
FIG. 2.--Simple pneumoconiosis. Early P.M.F. in the left upper lobe, and a dense shadow extending from the right hilum to the periphery of the lung.
FIG. 3.--Simple pneumoconiosis and a dense, ill-defined shadow in the right mid-zone.
FIG. 4.--N[inimal simple pneumoconiosis. A small opacity at the periphery of the first left intercostal space, and a large, ill-defined opacity at the periphery of the right lower' zone.
To face p. 244.
P L A T E IV
FIG. 5.--Simple pneumoconiosis. Early P.M.F. in both upper lobes and partial atelectasis of the right middle lobe.
FIG. 6.--Right lateral view showing partial
atelectasis of the middle lobe.
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whereas a tumour can arise in any part of the lung, P.M.F. usually arises in the upper part, in either an upper lobe or the apex of a lower lobe. Thus a solitary lesion in a basal segment is more likely to be cancer, in which respect case 3 was exceptional. A large opacity in any part of one lung-field, in the absence of other opacities, is unlikely to be caused by P.M.F., which (except in its early stages) is usually bilateral, and in this respect also case 3 was unusual. The shape, size, and density of an X-ray shadow are of little help in distinguishing lung cancer from P.M.F., but the latter is generally less clearly outlined. This difference is not applicable if the tumour is located in an area of massive fibrosis, as it was in case 2. The most reliable guide to the patholog-y of a pulmonary lesion is its rate of growth as seen on serial X-rays. The growth rate of P.M.F. is comparatively slow and only appreciable on the X-ray over a period of several years, whereas the growth of lung cancer is more rapid and can be appreciated over a period of months or even weeks. There are exceptions, and rarely a small tumour remains radiographically unchanged for months or years before entering a phase of rapid expansion (Simon, I962 ) . The rate of growth can only be assessed if previous films are available for comparison--which they often are for miners, if all possible sources are searched, including the Coal Board, the Ministry of Pensions and the M.M.R. A peripheral pulmonary lesion in Caplan's syndrome may be mistaken for lung cancer (case 4)- The typical case, with rheumatoid arthritis and multiple circular shadows on the X-ray, presents no problem. Diagnosis is more difficult if there is a solitary pulmonary lesion (case 4), or if the appearance of the X-ray shadow precedes the onset of arthritis. The rate of growth of a pulmonary rheumatoid nodule is comparable to that of a malignant lesion, and in such a case the occurrence ofjoint symptoms might be mistaken for hypertrophic osteoarthropathy. Although the lesions of massive fibrosis are typically solid, on occasion they excavate due to ischmmic necrosis or concomitant tuberculosis (Kdlpatrick, Heppleston, and Fletcher, 1954). The appearances on the X-ray, namely of a thick-walled abscess, often resemble those of a cavitating carcinoma of the lung. In such cases the clinical history should help to distinguish between the two, for excavation in P.M.F. is preceded by melanoptysis, or the expectoration of sputum blackened with coal-dust. The sputum should also be examined for malignant cells and tubercle bacilli. Bronchography can be a useful aid to differential diagnosis. A peripheral carcinoma usually occludes the bronchus proximal to it, the filling defect on the bronchogram being either abrupt or of the " r a t tail" variety, and at a later stage there is evidence of occlusion of the surrounding bronchioli (Molmar and Rieble, I963). By contrast, in P.M.F. the bronchographic appearances are essentially of bronchial distortion rather than occlusion. A personal review of 15 bronchograms in cases of complicated pneumoconiosis showed that irregularity of the small bronchi and displacement towards areas of massive fibrosis were the commonest abnormalities, and in three cases there was bronchiectasis associated with concomitant tuberculosis. In only one bronchogram was there an abrupt
I46
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filling defect of a segmental bronchus in relation to massive fibrosis which might have been mistaken for carcinoma. Similar bronchographic appearances to these in P.M.F. have been reported by Rosmanith and Bruckner (1958) and by Gernez-Rieux and colleagues (i 961 b), who described the essential changes as those o f " bronchitis deformans". Although most of this discussion has been confined to the diagnosis of peripheral tumours, lung cancer more commonly arises in one of the main bronchi. Here it may cause pneumonia or atelectasis, and produce a segmental or lobar X-ray shadow of a type rarely seen in pneumoconiosis. Case 5 is an exception, in which an enlarged anthracotic gland exerted pressure on the middle lobe bronchus and on the oesophagus, causing atelectasis and dysphagia. Middle lobe atelectasis has also been reported by Ellis (I964) in five coalminers and a foundry worker with simple pneumoconiosis; active tuberculosis was confirmed in four of them. The author considered the condition was secondary to active or healed tuberculous endobronchitis, perhaps following invasion by an adjacent tuberculous lymph node, although enlarged glands were evident in only one of his patients. Atelectasis has also been described as a complication of enlarged pulmonary lymph glands in classical silicosis (Kergin, 1952 ; Paul, I96I ). Inevitably cases arise in which the diagnosis of a pulmonary lesion cannot be achieved without a thoracotomy. However, even after inspection and palpation of a lesion the surgeon may still be unable to distinguish between lung cancer and massive fibrosis or between malignant and anthracotic lymph glands, so closely can they resemble each other. This situation sometimes results in a pulmonary resection for what is later found to be a pneumoconiotic lesion (case 3). This type of error is particularly liable to occur if the patient is an ex-miner and the relevant occupational history has not been elicited. I f there has been a thorough clinical and radiological assessment before operation the surgeon will be aware of the possibilities and if necessary will take a biopsy for frozen section before proceeding to pulmonary resection.
Summary The diagnosis of lung cancer in men who have worked in coal-mines is complicated by the clinical and radiographic similarities of malignant and pneumoconiotic lesions. Cases are reported which illustrate some of the problems, namely the similarity between peripheral lung cancer and coalworkers' massive fibrosis, between lung cancer and Caplan's syndrome, and between bronchial obstruction caused by a tumour and by an anthracotic lymph gland. Criteria for distinction between the two types of lesion are discussed, and bronchography as an aid to differential diagnosis is referred to. ACKNOWLEDGEMENTS I wish to thank Dr. H. M. Foreman, Dr. L. R. West, Mr. D. M. E. Thomas, and Mr. H. R. S. Harley for permission to write about patients who were under their care at Sully Hospital. I am most grateful to Dr. L. R. West for advice about the interpretation of bronchograms. Mr. F. Midgley prepared the photographic illustrations.
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