Retroperitoneal and pleural fibrosis in an insulator working in power plants

Abstract

We describe a case history of a former insulator who developed concomitant retroperitoneal and pleural fibrosis. In his work, the patient had been exposed on a daily basis to asbestos dust while demolishing and installing pipeline insulations. The heavy asbestos exposure was confirmed by a high level of asbestos content in his autopsy lung sample. We propose that both retroperitoneal fibrosis and diffuse pleural thickening were induced in our patient by an abundant amount of amphibole asbestos fibres found in his lung and retroperitoneal tissues.

CASE PRESENTATION

In 1979, a 52-year-old man with slowly progressing back and abdominal pain was admitted to our hospital. He had previously been healthy, had used no medication and had smoked for 10 pack-years. Laboratory tests showed elevated creatinine and erythrocyte sedimentation rates. The findings of the intravenous urography–bilateral hydronephrosis and medialisation of the ureters–suggested the rare fibroinflammatory disorder, retroperitoneal fibrosis (RPF). Laparotomy revealed a large fibrous mass that covered the ureters and the major abdominal vessels (fig 1C). The ureters were dissected from the fibrous mass and wrapped in the omentum to prevent restenosis. The renal function remained stable until 1990, when a relapse of RPF was treated with corticosteroids.

Figure 1.

(A) Chest radiograph taken in 1998 showing intense profusions suspected of being partially parenchymal and pleural thickening. (B) Chest high resolution computed tomography (HRCT) taken in 2002 showing bilateral partly calcified diffuse pleural thickening (arrowheads) with rounded atelectasis (black arrow). (C) Abdominal CT scan taken in 1994 showing a para-aortal thick fibrous mass.

In 1989 the patient was referred because of suspicion of occupational lung disease. He had worked from 1952 to 1986 as an insulator in power plants. In his work, he was exposed to asbestos dust daily while demolishing old pipeline insulation and installing new insulation. His cumulative asbestos exposure was estimated to exceed 25 fibre-years, which is sufficient to induce asbestosis. Chest x ray showed extensive bilateral fibrotic lesions (fig 1A), some of which were anticipated on the x ray taken at the time of the RPF diagnosis. Asbestosis, bilateral pleural adhesions and parietal pleural plaques were diagnosed and accepted as occupational diseases. Occupational asbestos exposure was also proposed as the cause of RPF, but it was not accepted by the insurance company.

In 2002 the lung fibrosis was re-evaluated using chest high resolution computed tomography (HRCT). There was extensive bilateral diffuse pleural thickening (DPT) with rounded atelectasis (fig 1B), but the parenchymal fibrosis was only mild. DPT may cause substantial loss of lung function.¹ During 14 years of follow-up, our patient’s vital capacity decreased from 2.8 litres (55% of normal) to 2.00 litres (47%) and diffusion capacity decreased from 77% to 61% of the expected normal value. He had moderate exertional dyspnoea and chronic productive cough.

In 2004 the patient developed unstable angina pectoris. He underwent coronary revascularisation that was complicated by postoperative stroke. Rehabilitation was difficult, interrupted by several episodes of cardiopulmonary failure, some aggravated by iatrogenic adrenal insufficiency. The patient developed chronic hypercapnia and died a year later through cardiorespiratory failure at the age of 79 years.

The medico-legal autopsy showed bilateral pleural plaques and widespread thickening and adhesions of the visceral pleura. The retroperitoneal structures were adherent and the abdominal aorta was intensely calcified. There was no continuity between the pleural and retroperitoneal fibrotic lesions. Histology showed fibrosis with inflammatory cell infiltration both in the pleural and retroperitoneal tissue. Unfortunately the lungs were not distended before sampling and reliable post mortem grading of the lung parenchymal fibrosis was not possible. There was a very high concentration of asbestos fibres in the lung parenchyma (59 million fibres/g) consistent with heavy asbestos exposure. The asbestos content of the abdominal lymph nodes and retroperitoneal fibrous tissue was also substantial and the same amphibole asbestos fibres were present (table 1). The cause of death was asbestos related lung disease, with atherosclerotic heart disease acting as a contributing condition.

Table 1.

Asbestos fibres in tissue samples of the patient with retroperitoneal fibrosis

Tissue	Number of fibres detected			Asbestos content*
	Anthophyllite	Amosite	Crocidolite	106 fibres/g of dry tissue
Lung parenchyma	18	3	5	59·00
Lymph node at the level of renal arteries	13	1	1	0·80
Lymph node behind the proximal end of the abdominal aorta	11	1	4	1·01
Retroperitoneal fibrosis mass, right side	0	4	3	0·14
Retroperitoneal fibrosis mass, left side	1	1	6	0·09

*Asbestos fibres over 1 μm in length were detected using scanning transmission electron microscopy. The concentration of asbestos fibres is given according to the original dry weight of the samples.

DISCUSSION

At the time of diagnosis the patient did not have any other known risk factors for RPF than asbestos exposure (for example, ergotamine medication, abdominal aortic aneurysm, abdominal trauma or infection),² and no signs of autoimmune disease were found during the follow-up. We propose that both RPF and DPT were induced in our patient by the abundant amount of amphibole asbestos fibres found in his lung and retroperitoneal tissues. This case also illustrates the progressive nature of asbestos induced DPT causing the lungs to “shrink” and leading to respiratory failure.

This is one of several patients with retroperitoneal fibrosis referred to our clinic of occupational medicine for suspicion of asbestos related lung disease. Using these cases, we have argued that there may be a causal relationship between occupational asbestos exposure and RPF, which was supported by our case–control study.³ There are no data indicating that non-occupational asbestos exposure would be associated with RPF. Recently, two cases of RPF and pleural fibrosis continuing into the mediastinum have been reported by Cottin et al.⁴ The asbestos exposure of these men appeared to be slight, but no other causative factors were found. In our unpublished series we have observed three similar asbestos exposed RPF patients with large pleural masses extending into the anterior mediastinum.

LEARNING POINTS

• Retroperitoneal fibrosis (RPF) is a rare multi-aetiologic fibroinflammatory condition that causes hydronephrosis and renal failure.

• Asbestos fibres reach the retroperitoneal space and may induce retroperitoneal fibrosis.

• All RPF patients should be evaluated for asbestos exposure, and chest high resolution CT should be performed, if pleural or lung fibrosis is suspected on the chest x ray.