Background: Systemic vasculitis (SV) and progressive vascular changes are the most important basic complications of systemic sclerosis (SSc).
Objectives: The aim of this study was to determine:
(1) the prevalence (existence) of vasculitis or vascular changes in various organs of SSc patients,
(2) the frequency, severity, and stages of vasculitis in investigated organs.
Methods: A non-selected autopsy population of 11 in-patients (female 10, average age: 53.6 years; male 1, age of 65 years at death) with SSc was studied.
The existence of vasculitis and vascular changes in various organs, the frequency (incidence) of vasculitis and changes in blood vessels of different sizes, the severity (density), and the stages of vasculitis and changes in blood vessels of different sizes were determined histologically.
Results: (1) Vasculitis or structural changes of blood vessels were observed in all (100%) investigated organs of all patients.
(2) The frequency (incidence) of involved blood vessels by size (in absolute value and in relative % of the total sum of prevalence n=425), the severity (density) of vasculitis or vascular changes in involved blood vessels (in absolute value and in relative % of the total sum of severity n=736), furthermore the stages of vasculitis or vascular changes involving different size of blood vessels (in absolute value and in relative % of the total sum of registered stages n=998) are summarized in Table. Vasculitis was usually severe in the frequently involved organs. Vasculitis and vascular changes existed mostly in advanced stages of pathological processes, and were accompanied by pronounced (multifocal,or diffuse) interstitial fibrosis, or sclerosis.
Table:

Prevalence, Frequency, Severity and Stages of Vasculitis in SSc
Organ	Prevalence of SV / Pts	%	Incidence (rel%) of SV / Organ	Density (rel%) of SV / Organ	Stages (rel%) of SV / Organ
Lung	11 of 11	100 %	11.5	11.8	11.5
Kidney	11 of 11	100 %	10.5	13.3	12.6
Spleen*	9 of 9	100 %	10.3	11.8	9.6
Pancreas*	9 of 9	100 %	9.9	9.1	10.7
Heart	11 of 11	100 %	9.9	9.9	8.9
Liver*	7 of 7	100 %	9.4	7.9	8.7
G-I Tract*	9 of 9	100 %	8.5	9.3	10.4
Skeletal muscle*	10 of 10	100 %	8.2	7.1	8.0
Adrenal glands*	7 of 7	100 %	8.1	7.8	7.3
Peripheral nerve*	8 of 8	100 %	5.2	4.9	5.2
Skin	11 of 11	100 %	5.2	4.7	4.9
Brain	6 of 6	100 %	3.3	2.4	2.2
Total			100 %	100 %	100 %
* Some organs were not available for evaluation.

Conclusion: The presence of vasculitis or structural changes of the vessel walls in all autopsy patients reflects the significance of these processes in the pathogenesis of the progressive systemic sclerosis.
The simultaneously existing different stages of vasculitis or vascular changes indicate the recurrent and progressive nature of these pathological processes.
The frequency, the severity and the recurrence of vasculitis or vascular changes represent different aspects of the same phenomenon usually running parallel to each other in different vessels in various organs. Vasculitis and vascular changes are usually severe in the frequently involved organs.
The high prevalence (incidence) of vasculitis and vascular changes in the lungs, kidneys, spleen, pancreas, and heart should warn to carefully evaluate the clinical and laboratory evidence pointing to involvement of these organs in SSc.
The frequently involved gastrointestinal tract may be a good target for biopsy to confirm the presence of systemic vascular changes (and consecutive submucosal fibrosis) in SSc patients. (N.B. submucosa should be present in the biopsy material).