Tuberculous septic arthritis of the hip with large abscess formation mimicking soft tissue tumors: A case report

Background Tuberculous septic arthritis is an infection that occurs inside the joint or synovial fluid and joint tissues caused by Mycobacterium tuberculosis . It may show wide variability of clinical symptoms and imaging appearance, ranging from asymptomatic with a normal radiographic examination to severe joint pain along with joint destruction, osteomyelitis, and abscess formation. This article presents radiographic and MR imaging appearance from a case of tuberculous septic arthritis with large abscess formation mimicking soft tissue tumor. Case presentation We reported a 32-year-old female with a slowly enlarging lump on her right proximal thigh within the last 4 months along with slowly progressing joint pain. Both radiographic and MR images showed destruction of the femoral head and acetabular roof, with a formation of large rim-enhanced abscess that extending superficially and distally until mid-thigh. The patient underwent open drainage surgery and excisional biopsy. Histopathological examination showed chronic granulomatous inflammation caused by tuberculous infection. Conclusion MR imaging combined with radiographic and clinical information played a very important role in the diagnosis of tuberculous septic arthritis with abscess, and to differentiate it from soft tissue neoplasms.