Clinical Manifestations of Pulmonary Mucormycosis in Recipients of Allogeneic Hematopoietic Stem Cell Transplantation: A 21-Case Series Report and Literature Review

INTRODUCTION: Mucormycosis is a rare, invasive disease caused by opportunistic pathogens related to the Mucorales order with high fatality rates in immunocompromised hosts, especially in recipients of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Diagnosis and treatment of pulmonary mucormycosis in recipients of allo-HSCT remains challenging. PURPOSE: The aim of this study is to summarize and analyze the clinical features of pulmonary mucormycosis in recipients of allo-HSCT to explore further clinical research directions for this rare fungal infection in the particular populations. METHODS: We retrospectively reviewed pulmonary mucormycosis in patients who received allo-HSCT in our hospital from January 2010 to December 2020. A total of 21 patients fulfilled the diagnostic criteria for pulmonary mucormycosis according to the European Organization for Research and Treatment of Cancer and Mycoses Study Group (EORTC/MSG) criteria. Demographic and clinical data, mycological and histopathological records, and treatment and prognosis data were collected. Clinical variables were compared between survivors and nonsurvivors. The survival days of patients with and without graft-versus-host disease (GVHD) and hemoptysis were compared separately. RESULTS: Most of the recipients of allo-HSCT were male patients with a mean age of 43 years. Acute myeloid leukemia (AML) was the most common primary hematologic malignancy. Extrapulmonary involvement accounted for 28.6%, of the cases, including central nervous system (n = 5) and skin and soft tissue (n = 1). The median time to infection was 96 days after allo-HSCT. Clinical presentations were nonspecific, including fever (76.2%) and cough (85.7%), as well as dyspnea (19.0%), chest pain (38.1%), and hemoptysis (61.9%). Ground-glass infiltrates (95.0%) and nodules/masses (80%) were the most common radiographic patterns on chest CT. The most common pathogen was Rhizopus (63.2%), and breakthrough infection accounted for 90.5%. Fifteen of the patients died within one year, and the median time from diagnosis to death was 47 days. CONCLUSION: Mucormycosis is a fatal infection disease. Opportunistic infections in recipients of allo-HSCT are mainly breakthrough infections and may have a seasonal distribution (summer and autumn) and more cases of death in autumn. The marked reversed halo sign can be seen both in the initial stage of infection and after antifungal treatment. In our case series, patients with pulmonary mucormycosis with extrapulmonary involvement 100% died within one year. There are more patients with GVHD before infection and hemoptysis in nonsurvivors than survivors within 100 days. Patients with GVHD before infection and hemoptysis have a shorter survival time than those without.