A 64-year-old woman experienced persistent vaginal bleeding for three months, which was found to be caused by a rare fungal infection (Aspergillus quadrilineatus) in her uterus. Through tissue examination and molecular testing, doctors identified the fungus and found it was sensitive to common antifungal medications. The patient was successfully treated with antifungal medication combined with surgical cleaning of the uterus, making a complete recovery. This case highlights that fungal infections should be considered when patients have abnormal vaginal bleeding, even if they appear otherwise healthy.