P306 Scedosporium spp. and Lomentospora prolificans, fungal agents with unexpected vascular tropism
Authors: Vignals Carole , Lanternier Fanny , Garcia-Hermoso Dea , Emmerich Joseph , Bronnimann Didier 
Published: September 2022

Abstract

Poster session 2, September 22, 2022, 12:30 PM - 1:30 PM

Objectives
Invasive scedosporiosis and lomentosporiosis are deadly fungal infections due to Scedosporium spp. and Lomentospora prolificans. The Scedosporiosis/lomentosporiosis Observational Study (S.O.S.) highlighted for the first time a frequent vascular involvement in these infections including aortitis and peripheral arteritis (PA). We here describe the clinical, microbiological, radiological and anatomopathological characteristics of these vascular infections.

Methods
We retrospectively reviewed cases of arteritis (with the exception of central nervous system arteritis) from the S.O.S. cohort and from the literature.

Results
Seven cases of vascular infections were identified from the S.O.S. cohort representing 24% (7/29) of the disseminated scedosporiosis/lomentosporiosis. Four cases had both aortitis and PA, 2 patients were diagnosed with PA and one patient with aortitis. A total of 9 aortitis and 4 PA cases were identified from the literature. All 20 cases were proven scedosporiosis/lomentosporiosis. The main species was S. apiospermum [60% of cases (12/20)] followed by L. prolificans [35% of cases (7/20)]. One infection was caused by both species. An underlying immunosuppression was present in 70% of the cases (14/20, with 10 cases of solid organ transplantation and 3 cases of hematologic malignancies). The main risk factor in immunocompetent patients was a previous cutaneous trauma (4/6). Interestingly, vascular involvement was identified at diagnosis of the scedosporiosis/lomentosporiosis in only half of the cases. Aortitis was mainly abdominal (8/13). Various PA localizations were reported with frequent iliac or femoral involvement (4/10). Arteritis was the only localization in only 10% (2/20) of the scedosporiosis/lomentosporiosis, other sites involved being mainly osteoarticular (10/20), and pulmonary (9/20) followed by central nervous system (5/20), cutaneous localizations (4/20), and endocarditis (4/20). Of note, three-quarters of the cases were disseminated. Aneurysmal lesion was the most frequent imaging aspect (8/11 of aortitis and 6/10 of PA) which was complicated by a rupture in half of the aortitis (4/8) and only one PA (1/6). Vascular wall thickening (2/11 of aortitis and 1/10 of PA) and perivascular abscess (1/11 and 1/10, respectively) were more rarely described. Hypermetabolism was constant on PET-CT scan when performed (6/6). When available (11/20), pathological analysis showed an invasion of the artery wall by fungal hyphae (10/11), particularly in the media and the adventice. A total of 3-months of mortality related to infection was 44% (8/18), rising to 71% (5/7) in case of fungemia.

Conclusion
The vascular tropism of Scedosporium spp. and L. prolificans underlies the necessity of vascular imaging in the management of these infections, especially in case of dissemination seeking in particular aneurysmal lesions of the abdominal aorta and iliofemoral arteries.