OBJECTIVES: Emerging invasive fungal infections (IFI) have become a notable challenge. Apart from the more frequently described fusariosis, lomentosporiosis, mucormycosis, scedosporiosis, and certain dematiaceae or yeasts, little is known about extremely rare IFI. METHODS: Extremely rare IFI collected in the FungiScopeⓇ registry were grouped as Dematiaceae, Hypocreales, Saccharomycetales, Eurotiales, Dermatomycetes, Agaricales, and Mucorales. RESULTS: Between 2003 and June 2019, 186 extremely rare IFI were documented in FungiScopeⓇ. Dematiaceae (35.5%), Hypocreales (23.1%), Mucorales (11.8%), and Saccharomycetales (11.3%) caused most IFI. Most patients had an underlying malignancy (38.7%) with acute leukemia accounting for 50% of cancers. Dissemination was observed in 26.9% of the patients. Complete or partial clinical response rate was 68.3%, being highest in Eurotiales (82.4%) and in Agaricales (80.0%). Overall mortality rate was 29.3%, ranging from 11.8% in Eurotiales to 50.0% in Mucorales. CONCLUSIONS: Physicians are confronted with a complex variety of fungal pathogens, for which treatment recommendations are lacking and successful outcome might be incidental. Through an international consortium of physicians and scientists, these cases of extremely rare IFI can be collected to further investigate their epidemiology and eventually identify effective treatment regimens.

Center of Microbiological Research of Cesar Rosario Pumarejo de López Hospital Laura Daniela Clinic Médicos Clinic LTDA Valledupar Colombia

Centre for Diseases and Microbiology Laboratory Services ICPMR New South Wales Health Pathology Westmead Hospital Sydney NSW Australia; The University of Sydney Westmead Sydney NSW Australia

Clinical and Translational Fungal Working Group University of California San Diego La Jolla CA United States; Division of Infectious Diseases and Global Public Health Department of Medicine University of California San Diego San Diego CA United States; ECMM Excellence Center for Clinical Mycology Section of Infectious Diseases and Tropical Medicine and Division of Pulmonology Medical University of Graz Graz Austria

Clinical Microbiology and Parasitology Department University Hospital La Paz Madrid Spain

Department of Infectious Diseases Royal Perth Hospital Perth WA Australia; School of Pathology and Laboratory Medicine University of Western Australia Perth WA Australia

Department of Internal Medicine Division of Infectious Diseases University of Alabama at Birmingham AL United States; Medical Service Birmingham VA Medical Center AL United States; Institute for Human Virology University of Maryland School of Medicine Baltimore MD United States

Department of Internal Medicine Division of Infectious Diseases University of California Davis Medical Center Sacramento CA United States; Department of Medical Microbiology and Immunology University of California Davis Medical Center Sacramento CA United States

Department of Internal Medicine Hematology and Oncology Masaryk University Brno Czech Republic; University Hospital Brno Brno Czech Republic; Institute of Hematology and Blood Transfusion Prague Czech Republic

Department of Medical Microbiology Postgraduate Institute of Medical Education and Research Research Chandigarh India

Department of Medicine Division of Infectious Diseases University of Pittsburgh Pittsburgh Palestine State of United States

Department of Medicine Section of Infectious Diseases and Global Health University of Chicago Chicago IL United States

Department of Microbiology Government Medical College and Hospital Chandigarh India

Department of Microbiology School of Medicine Universidad Autonóma de Nuevo León Nuevo León Mexico

Department of Microbiology Sri Ramachandra Medical College and Research Institute SRIHER Chennai India

Department of Oncology and Hematology Hôpitaux Universitaires de Strasbourg and Université de Strasbourg Inserm UMR S1113 IRFAC Strasbourg France

Department of Pediatrics Division of Pediatric Infectious Disease Okan University School of Medicine Istanbul Turkey

Division of Infectious Diseases Departments of Medicine Microbiology and Immunology Research Institute of the McGill University Health Centre Montreal QC Canada

epartment of Clinical Microbiology Mycology and Antibiotic Therapy National Research Center for Hematology Moscow Russia

Institut des Agents Infectieux Parasitologie Mycologie Hôpital de la Croix Rousse Hospices Civils de Lyon Lyon France; Integrative Physiology of the Brain Arousal Systems Centre de Recherche en Neurosciences de Lyon INSERM U1028 CNRS UMR 5292 Faculté de Médecine Université Claude Bernard Lyon 1 Lyon France

Institute of Hygiene and Medical Microbiology Medical University of Innsbruck Innsbruck Austria

Invasive Fungi Research Center Communicable Diseases Institute Mazandaran University of Medical Sciences Sari Iran

Laboratory of Antimicrobial Chemotherapy Ion Ionescu de la Brad University Iași Romania

Mechnikov North Western State Medical University St Petersburg Russian Federation

MTA SZTE Lendület Mycobiome Research Group Szeged Hungary; Department of Microbiology Faculty of Science and Informatics University of Szeged Szeged Hungary

Parasitologie Mycologie Médecine Tropicale CHU de Tours France; Centre d'Etude des Pathologies Respiratoires Unité Inserm U1100 Université de Tours Tours France

Parasitology Mycology Unit University Hospital Center Fort de France Martinique French West Indies

Pediatric Hematology Oncology Department of Mother and Child Azienda Ospedaliera Universitaria Integrata Verona Italy

Research Institute McGill University Health Centre Infectious Diseases and Immunity in Global Health Program Montreal QC Canada

University of Cologne Faculty of Medicine and University Hospital Cologne Department 1 of Internal Medicine Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf Cologne Germany

University of Cologne Faculty of Medicine and University Hospital Cologne Department 1 of Internal Medicine Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf Herderstrasse 52 54 50931 Cologne Germany

University of Cologne Faculty of Medicine and University Hospital Cologne Department 1 of Internal Medicine Center for Integrated Oncology Aachen Bonn Cologne Duesseldorf University of Cologne Cologne Germany

Wisplinghoff Laboratories Cologne Germany; Institute for Medical Microbiology University of Cologne Cologne Germany; Institute for Virology and Microbiology Witten Herdecke University Witten Germany

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