A10-year-old child with pain and mass in right lumbarregion with no fever, with right hip flexed and X-ray shows spine changes. Most probable diagnosis is:

ANS. A# Psoas abscessAn abscess in the psoas muscle of the abdomen may be caused by lumbar tuberculosis. Owing to the proximal attachments of the iliopsoas, such an abscess may drain inferiorly into the upper medial thigh and present as a swelling in the region. The sheath of the muscle arises from the lumbar vertebrae and the intervertebral discs between the vertebrae. The disc is more susceptible to infection, from tuberculosis and Salmonella discitis. Ihe infection can spread into the psoas muscle sheath.Treatment may involve drainage and antibiotics