Brodie's Abscess of Posterior Ilium with Gluteal Syndrome, an Unusual Cause of Paediatric Low Back Pain: A Case Report.

Brodie's abscess is a variety of subacute osteomyelitis with a long duration of presentation and intermittent pain. It usually involves the metaphyseal region of long bones of the lower limbs. Brodie's abscess of pelvic bone is very rare. Involvement of posterior ilium with gluteal syndrome is extremely unusual and can be easily missed or misdiagnosed. We present a 9-year old boy who reported to us with intermittent low back pain of three months duration without any other constitutional symptoms. Clinically, there was mild tenderness over the posterior ilium. Computed tomography showed a lytic lesion in the posterior ilium with a breach in the outer cortex. MRI and bone scan were suggestive of inflammatory pathology. Keeping infective, tubercular and benign bone tumors as differential diagnoses, open biopsy and curettage were done. Staphylococcus aureus was cultured and histopathology was suggestive of osteomyelitis. The patient received appropriate antibiotics for six weeks. He was asymptomatic till 18 months of follow up without any recurrence. We present this case because of its rarity and unusual presentation as gluteal syndrome and low back pain, and its resemblance to other pelvic and sacroiliac joint pathologies which are often missed or misdiagnosed in paediatric patients.