A Rare Case Report on Xanthogranulomatous Osteomyelitis of Hip Mimicking Tuberculosis and Review of Literature

Abstract

Xanthogranulomatous osteomyelitis (XO) is a rare chronic inflammatory process characterized by the presence of a large number of lipid-containing macrophages with lymphocytes and plasma cells. We present a case of XO of the hip in a 50-year-old woman with pain in the left hip for 28 months. The patient had a history of taking anti-tuberculosis chemotherapy for five months. Laboratory data revealed an increased erythrocyte sedimentation rate and C-reactive protein (CRP) level. Plain radiographs showed the destruction of the femoral head with arthritis and subluxation. Magnetic resonance imaging (MRI) was suggestive of tubercular infection of the left hip and a benign lesion in the left ilium. The histopathologic examination of the specimen demonstrated the presence of dead bone surrounded by lymph-plasma cells, foamy cells, and histocytes, which was consistent with XO, and culture was positive for Staphylococcus aureus infection. The patient was successfully treated with resection arthroplasty and antibiotics. It is important for the surgeons to keep XO in the list of differentials in cases with lytic lesions of bone and assessment should include microbiological culture along with the biopsy.

Keywords: foamy macrophages; infection; tuberculosis hip; tumor; xanthogranulomatous inflammation.

Figure 1. Plain anteroposterior radiographs of pelvis with both hips with the gross destruction of the femoral head with head subluxation (black arrow)

Figure 2. Sagittal T1-weighted MRI image of left hip showing destruction of the left femoral head with superolateral hip dislocation (white arrow) and hypointense focal lesion of the left ilium (black arrow)

MRI, magnetic resonance imaging

Figure 3. Sagittal T2-weighted MRI showing fluid collection around left hip (white arrow head) with a hyperintense focal osseous lesion in the left ilium (white arrow)

MRI, magnetic resonance imaging

Figure 4. Plain anteroposterior radiographs of pelvis with left femoral head and neck resection and proximal migration of shaft (black arrow)

Figure 5. Histopathology sample of resected femoral head

Figure 6. Composite photomicrograph image showing bony spicule with foamy macrophage (hematoxylin and eosin stain, 100x magnification)

Black arrow: foamy histiocyte; white arrow: dead bony spicule; black arrowhead: acute inflammatory infiltrate

Figure 7. Composite photomicrograph image showing foamy macrophages histiocytes, and plasma cells (hematoxylin and eosin stain, 100x magnification)

Yellow arrow: foamy macrophages