A retrospective analysis across two large U.S. academic centers provides new insight into the clinical features, management strategies, and outcomes of Aspergillus osteomyelitis, a rare manifestation of invasive aspergillosis.
The findings were presented as abstract P-1712 at IDWeek 2025, in Atlanta.
What Is Aspergillus osteomyelitis?
“Aspergillus osteomyelitis is an uncommon manifestation of aspergillosis, has quite mixed presentations, and there's limited data out there,” said Adam G. Stewart, MBBS, PhD, an infectious diseases physician and an assistant professor at MD Anderson Cancer Center, in Houston.
Prior studies, Dr. Stewart noted, have suggested that vertebrae, ribs, sternum, and cranial bones are most commonly involved, and “combined antifungal therapy and surgery” may reduce relapse and clinical failure.
A Need for Better Understanding
To better characterize this condition, Dr. Stewart and his colleagues queried the Mass General Brigham Research Patient Data Registry to identify adult cases of proven or probable Aspergillus osteomyelitis at Massachusetts General Hospital and Brigham and Women’s Hospital between January 2000 and January 2023.
“The aim of our study was to describe the epidemiology, clinical and radiological features, as well as microbiology management and outcomes of proven and probable Aspergillus osteomyelitis across two centers,” Dr. Stewart said.
A total of 27 adults met inclusion criteria, with a median age of 68 years. Predisposing conditions were common and included solid organ transplantation—primarily cardiac and lung (26%)—as well as hematologic malignancy or stem cell transplant (22%), diabetes mellitus (52%), and other forms of immunosuppression (15%). Mechanisms of infection varied, with contiguous spread accounting for nearly half of cases (48%), followed by direct inoculation (37%) and hematogenous spread (15%).
Microbiologically, Aspergillus fumigatus was by far the most common cause of infection at 63%, followed by Aspergillus flavus at 26%. Diagnostic performance of serum galactomannan was limited: It was positive in only 36% of tested patients, with durations of positivity ranging from four to 357 days.
A Combined Treatment Approach
Most patients (96%) received combined surgical and antifungal therapy.
“Surgery and antifungals occurred in almost all patients, and only one patient was treated purely on medical rounds alone,” Dr. Stewart said. Voriconazole was the most frequently used definitive antifungal agent, administered in 78% of cases.
Outcomes were more favorable than those typically reported for other forms of invasive aspergillosis. Overall, 66% of patients achieved a complete or partial response or were placed on suppressive therapy, and 90-day mortality was 22%.
“These important clinical outcomes, such as mortality, may be more favorable when compared to other forms of invasive aspergillosis,” Dr. Stewart said, adding that this may reflect “localized disease which could be surgically resected or risk factors of the host.” As expected, he added, “immunosuppressive conditions are predictably overrepresented in patients with aspergillosis involving bone.”
Dr. Stewart reported no relevant financial disclosures.