18 January 2026
: Case report 
Multi-Pathogen Knee Infection, Including Treponema pallidum and Brucella: A Case Report
Challenging differential diagnosis, Rare disease, Clinical situation which can not be reproduced for ethical reasons
Youhan Yang
ABCDEF 1, Haitao Chen ADEF 1, Yinxian Wen ACDE 1, Qinglong Chai BCE 1, Yi Hua BEF 1, Xu Yang ACDEF 1*, Liaobin Chen ADG 1
DOI: 10.12659/AJCR.950156
Am J Case Rep 2026; 27:e950156
Figure 7 The synovial tissues of the joints were stained with hematoxylin-eosin and assessed by immunohistochemistry. (A) Examination of synovial tissue showed villous hyperplasia, fibrous tissue hyperplasia with mucous degeneration and vitreous degeneration; a few scattered lymphocyte and plasma cell infiltration, and scattered small foci of calcification and ossification were seen. Chronic suppurative inflammation with granulomatous tissue hyperplasia and obvious degeneration and necrosis of the tissue were seen locally. (B) Immunohistochemistry for syphilis in synovial tissue was negative.