The Great Imitator - Disseminated Tuberculosis Presenting as Baker's Cyst: A Case Report

Area of Science:

• Orthopedics
• Infectious Diseases
• Radiology

Background:

• Tuberculosis (TB) is a significant global health challenge, known for its diverse clinical presentations that can mimic other diseases.
• Baker's cysts, often associated with intra-articular pathology, can present diagnostic challenges, particularly in TB-endemic areas.

Observation:

• A 46-year-old male presented with a year-long posterior knee swelling, initially suspected to be pigmented villonodular synovitis (PVNS) based on MRI.
• The patient later developed a foot drop, prompting further investigation which revealed an L4-L5 spinal lesion and chest radiograph changes suggestive of TB.

Findings:

• Synovial biopsy of the knee confirmed tuberculous arthritis with a positive tuberculosis culture.
• Histology also confirmed tuberculous synovitis, and the patient had an associated spinal lesion.

Implications:

• This case underscores the importance of considering tuberculosis in the differential diagnosis of knee swellings, even when imaging suggests other conditions like PVNS.
• Early diagnosis and prompt initiation of anti-tubercular treatment, combined with surgical intervention and physiotherapy, led to a favorable clinical and radiological outcome.
• Clinicians in TB-endemic regions should maintain a high index of suspicion for tuberculosis and consider baseline chest radiography in patients with unexplained joint swelling.