Written informed consent was obtained from the patient. A 20-year-old man who presented with 2 month history of fever was admitted in our hospital on 8 October 2016. Without obvious cause, the patient had repeated chills and fever 2 months ago and the highest temperature raised to 39 C. He passed bloody stools and got abdominal pain during hospitalization. Physical examination was non-remarkable. Blood examination revealed 10.42 x 109 white blood cells/L, with 69.40% neutrophils and 16.17% lymphocytes. HIV antibody, immunochemistry, dengue antigen, hepatitis B, hepatitis C, influenza A, and influenza B antigen were all unremarkable. Chest and abdominal computed tomography (CT) scan showed ileocecus of ascending colon, and transverse colon showed diffuse thickening of the wall. The most obvious was in the transverse colon, which was considered as inflammation. On 13 October 2016, colonoscopy showed multiple segmental colon ulcers, which was considered as Crohn's disease or tuberculosis (Figure 1(a) and (b)). Pathology showed that there were a lot of acute and chronic inflammatory cells infiltration in lamina propria, submucosa, and muscle layer, and there were multiple granulomatous lesions without obvious caseous necrosis. In addition, the possibility of intestinal bacterial infection, inflammatory bowel disease (IBD), intestinal tuberculosis, lymphoma, histoplasmosis, and other diseases were excluded. It tended to be Crohn's disease, but tuberculosis was not excluded (Figure 2). The CTE of the small intestine showed that ileocecus and distal ileum were thickened and strengthened obviously after injection, so that the patient was conformed to Crohn's disease (Figure 3(c) and (d)). From 8-25 October, we gave him antibiotic treatments. Taking small intestinal computed tomography enterography (CTE), colonoscopy, and pathology into consideration, he was diagnosed as Crohn's disease and given glucocorticoids and immunosuppressant therapy from 20 October. After 5 days of treatment, the patient still had repeated fever, and the anti-infection treatment was upgraded to imipenem. However, his symptoms still have not improved. Therefore, we rechecked the colonoscopy. On 30 October, IBD was considered by colonoscopy, but it was not confirmed (Figure 1(a) and (b)). Meanwhile, tuberculosis was not excluded. Sample of intestinal biopsy was sent to our hospital and the Southern Hospital of Southern Medical University for examination. In the oral report of intestinal pathology in our hospital, the microbes with positive Periodic acid-Schiff (PAS) staining were examined, which were also seen in the intestinal pathology on 13 October. Therefore, we thought that we made a wrong diagnosis. Pathology reported that distal ileum, ascending colon, transverse colon, and sigmoid colon mucosa were infiltrated by a large number of tissue cells that had a large number of blue purple granules. Special staining showed purple blue particles with positive PAS staining and Gomori's Methenamine-Silver (GMS) staining. It was considered to be histoplasmosis. On 7 November, Southern Hospital Pathology Consultation Report described that a large number of tissue cells and multinuclear giant cells were seen in the lamina propria of ileum mucosa, and fungal spores were found in tissue cells, so that he was diagnosed as talaromycosis (Figure 4). On 8 November, immunologic testing showed that CD3 cells accounted for 17.40%, CD4 cells accounted for 11.50%, CD8 cells accounted for 4.10% and a CD4/CD8 ratio of 2.8. According to the pathology consultation report, he was finally diagnosed as talaromycosis. A treatment of itraconazole 0.2 g twice daily for a long term was given to him. The temperature dropped to normal and bloody stools disappeared after anti-fungal treatment for 5 days. We knew that he used to have a history of taking methamphetamine many times between July and August after inquiring about his medical history again. He reviewed colonoscopy in the hospital again on 17 January 2017. The examination results suggested that the intestinal inflammation subsided.