Thank you very much for sharing this interesting and complex case. I’m a student, still in training, and I truly appreciate the opportunity to follow these discussions and learn from your expertise.
I hope it’s alright if I share a humble thought based on the images and clinical background.
From what I understand, the 10-year-old girl is immunocompromised due to bone marrow aplasia and was recently treated for a severe perineal infection with fistula and colostomy. A firm medial soft tissue nodule was biopsied (suspected fungal), and now she presents with persistent daily fevers. While no obvious signs of contiguous osteomyelitis were found on MRI, a “bubbly” intramedullary lesion was seen in the tibial diaphysis, with some marrow edema and mild enhancement.
Although the X-ray appears normal, I wonder if this subtle bone marrow lesion could represent early fungal osteomyelitis, especially in the context of recent fungal suspicion and immunosuppression. I read that fungal osteomyelitis (like Aspergillus) can present with mild enhancement, marrow edema, and minimal or absent cortical changes in early stages, making it harder to detect on conventional radiographs.
I may be over-interpreting things, but I thought it might be something to consider as part of the differential. I would be really grateful to hear your thoughts and corrections.
Other considerations (just as thoughts from a student):
• Chronic nonbacterial osteomyelitis (CNO): From what I’ve read, this can show similar marrow findings, but it’s considered rare in immunocompromised patients and usually doesn’t cause persistent fever.
• Fibrous dysplasia or benign bone tumor: The bubbly morphology made me think of this as well, but it might be less likely in this acute infectious setting with fever and immunosuppression.
Conclusion (very humbly submitted):
Although the X-ray doesn’t show any clear abnormalities, the MRI findings made me wonder about early fungal osteomyelitis of the right tibia. Considering the bubbly lesion with faint enhancement and her persistent fever following a biopsy, I was curious whether this might justify:
• Performing fungal cultures or PCR from the biopsy sample (if still available),
• Possibly starting empiric antifungal therapy, given the high-risk context,
• And perhaps discussing with infectious diseases and orthopedics, if not already done.
I’m only a student, so these are just learning thoughts, and I would be very grateful for any corrections or guidance.
Warm regards,
Aseel from Belgium
On Thu, 12 Jun 2025 at 22:45, ‘Sergio wrote:
Hello everyone
This is a 10-year-old girl who was hospitalized with bone marrow aplasia and was about to receive a bone marrow transplant. She had an extensive infection in the perineal region, with the formation of a fistula, and underwent surgery involving a colonic bypass and colostomy. A hard nodule appeared in the medial soft tissues of the upper third of the leg, suspected to be a fungal infection, and she underwent biopsy. After the procedure, she began experiencing daily fevers and had an MRI to assess the possibility of contiguous osteomyelitis. I did not find anything suspicious for osteomyelitis, but a lesion appeared in the tibial diaphysis, somewhat "bubbly," associated with mildly enhancing bone marrow edema. The X-ray looks normal.
I would appreciate it if you could share your opinions.
