Objectives: The aim of this study was to determine:
1. the spectrum and incidence of complications related to progressive systemic sclerosis (SSc), such as systemic vascular changes, complex abnormalities of lungs, heart, kidneys, pancreas, and systemic amyloidosis,
2. the lethality of complications related to SSc,
3. the clinically missed diagnosis of these.
Methods: A randomized autopsy population of 12 in-patients with clinically confirmed SSc was retrospectively investigated.
The associated and basic disease, complication(s), and causes of death were determined by reviewing the clinical protocols and autopsy findings, and were confirmed histologically.
Results: In all patients SSc was the basic disease leading to death. The lethal complications were correctly recognized clinically in 11 of 12 cases (in one case uremia was missed).
In all patients SSc was complicated by a wide spectrum of vascular changes such as non specific inflammatory infiltration of vessel walls, involving all size of vessels, fibromuscular and/or intimal proliferation of medium size and small arteries (with, or without linear fibrinoid necrosis of the vessel wall), total fibrinoid necrosis of small arteries and arterioles (with, or without thrombosis), proliferation of pericytes and successive adventitial fibrosis.
The lungs showed complex abnormalities in 6 of 12 patients.
In the heart the complex vascular changes led to circulatory failure in 5 of 12 cases.
Complex nephropathy (in 10 of 12 patients)led to uremia in 6 of 12 cases.
Multifocal acute pancreatitis (of vascular origin) was observed in 6 of 12 cases.
Amyloidosis complicated SSc in 2 of 12 patients: one case of AA, and one of AL amyloidosis. AA amyloidosis was regarded as consequence of SSc, AL amyloidosis as consequence of associated B-cell lymphoma. Amyloidosis contributed to lethal heart failure in both cases.
Table:

Main complications and associated disease with cause of death
Sex/Basic disease	1. Complication(s	2. Complication(s	3. Complication(s	Cause of death	Assoc diseases
1. SSc/f	Compl.nephropathy	Pneumonitis	Pancreatitis	Uremia
2. SSc/m	Compl.nephropathy	Honeycomb lung	Pancreatitis	Uremia
3. SSc/f	Honeycomb lung	Compl.nephropathy	Myositis	Bronchopneumonia
4. SSc/f	Compl.nephropathy			Uremia
5. SSc/f	Compl.nephropathy	Pneumonitis	Pancreatitis	Uremia
6. SSc/f	Endo-myocardial f	Compl.nephropathy	Honeycomb lung	Heart failure	Tuberculosis
7. SSc/f	Compl.nephropathy	Myositis	Pancreatitis	Uremia	Meningeoma
8. SSc/f	Compl.nephropathy	Pneumonitis	Pancreatitis	Uremia
9. SSc/f	Honeycomb lung	Compl.cardiopathy	Compl.cardiopathy	Heart failure
10. SSc/f	Myocardiocytolysi	Myositis	Pancreatitis	Heart failure
11. SSc/f	Myocardial necros	Compl.cardiopathy	AA amyloidosis	Heart failure	Renal adenoma
12. SSc/f	Endo-myocardial f	AL amyloidosis		Heart failure	B cell lymphoma

Conclusion: SSc is a progressive multifocal process characterized by histological (vascular and interstitial) changes co-existing in different stages of their progression. In the course of the disease new foci develop, which increase in size and number, may become confluent, ultimately leading to diffuse, systemic interstitial sclerosis.
Diffuse fibrosis of the end stage is, however, not necessarily present if the patient dies of early renal insufficiency (6 of 12 SSc patients), of respiratory or heart failure (6 of 12 SSc patients), or due to some other complication.
Most lethal complications in SSc were clinically recognized; only one case of uremia was missed