A three-year-old boy with leukemia received a bone marrow transplant and developed a serious fungal lung infection caused by Neosartorya udagawae, a rare fungal pathogen. Despite receiving multiple antifungal medications at appropriate doses, the infection continued to worsen and spread in his lungs. Doctors ultimately had to surgically remove the infected portion of his lung (left upper lobe) to successfully treat the infection, and the child recovered completely without recurrence after three years of follow-up.