1. Prepared by Seena Tabibi MD
Reviewed by Sean Zhang MD PhD

A pediatric patient with recurrent high-risk leukemia status post bone marrow transplant. Recently, the patient was found to have relapse of their leukemia and was started on methotrexate, dexamethasone, and vincristine with the eventual goal to undergo additional therapy.

Several weeks after restarting treatment, the patient presented to the Emergency Department (ED) with a fever of 38.8 Celsius. A few days prior to presentation, the patient had fallen and scraped their skin. One day prior to presenting to the hospital, the site of the scrape was painful and swollen. Of note, the patient did not have cough, rhinorrhea, vomiting, or diarrhea and did not have any sick contacts at home.

Select ancillary studies and images are provided below:

White Blood Cell Count: 1.06 K/cu mm (Reference: 5.50-15.50 K/cu mm)
Hemoglobin: 7.1 g/dL (Reference: 11.8-13.7 g/dL)
Platelets: 37 K/cu mm (Reference: 150-350 K/cu mm)
Beta-D-Glucan: Positive (Reference: Negative)
Dermatopathology (Biopsy): GMS + and PAS + hyphal Forms identified throughout dermis and associated vessels

What is the most likely diagnosis?