PMC4400450_01
Extensive severe tophaceous gout. (A) Extensive tophi in both hands. (B) Extensive gluteal tophi. (C) CT scan imaging of hypervascularized gouty tophi in buttocks. The nature of the lesions was confirmed by fine needle aspiration biopsy.
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Physical findings included disorientation and extensive, severe tophi in hands, elbows, arms, thighs and gluteus (Figure 1A and B). The CT scan showed vascular enhancement in the subcutaneous tissue in both buttocks (Figure 1C).
Macrophage expression of 1alpha-hydroxylase. (A) Gouty tophi stained with H&E. Granulomatous inflammation is observed surrounding the matrix in which urate crystals, dissolved during the deprocessing procedure, were originally embedded. Original magnification x100. (B) Representative image of 1alpha-hydroxylase-expressing histiocytic mononucleated and multinucleated giant cells (arrows) in gouty tophi, as assessed by immunohistochemistry. Original magnification x100, detail x400. (C) 24-Hydroxylase-expressing 'macrophagic' mononucleated and multinucleated giant cells (arrows) in gouty tophi, as assessed by immunohistochemistry. Original magnification x100. (D) CD68 staining confirmed the macrophagic nature of cells surrounding the urate core (arrows) in gouty tophi. Original magnification x100.
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Thus, we performed immunohistochemistry for 1alpha-hydroxylase in biopsies from three additional tophaceous gout patients, which showed intense 1alpha-hydroxylase expression by macrophages and multinucleated cells surrounding tophi (Figure 2B). Furthermore, these cells stained for 24-hydroxylase (Figure 2C) and were confirmed to be CD68-positive macrophages (Figure 2D).