[Hymenolepis diminuta infection in an adult's lung: a case report]

Hymenolepis diminuta is a common parasite of rats and mice, but is very rare in humans with cases reported from various parts of the world. Here, we reported a case of Hymenolepis diminuta infection involving both the respiratory and digestive tracts in a 49-year-old male patient whose initial imaging and symptoms were strikingly similar to pneumonia. Since no disease-causing pathogens were found during routine examinations, we considered respiratory infection by specific pathogens before metagenomic next-generation sequencing of broncho-alveolar lavage fluid confirmed the diagnosis of Hymenolepis diminuta. After confirming the diagnosis, we retested the patient's stool repeatedly and found Hymenolepis diminuta eggs finally. To help doctors better understand this condition and avoid misdiagnosis, this article provided a summary of the clinical characteristics, diagnostic techniques, and therapeutic options for infection by Hymenolepis diminuta.