Fragments of extensively ulcerated synovial lining with dense infiltration by neutrophils, lymphocytes, plasma cells and macrophages with vascular endothelial proliferation and macrophages. No evidence of specific granulomas. No evidence of atypia or malignancy.
1.5-month history of right hip pain, with MRI findings suggestive of an abscess in the adjacent vastus lateralis muscle.
Soft tissue fragments collectively measured 2x1.7x0.7 cm, totally embedded.
Hip lesion, biopsy: