Pathological findings: Hematopoietic locations. A: Capillarized sinusoids of a bone biopsy with an inflammatory surrounding (HES ×400). B: CD31 positivity of the endothelial lining of capillarized sinusoids (×200). C: Spleen dilated sinusoids (smooth muscle actin ×100). D: Spleen larger cysts lined by a continuous layer of CD31 endothelial cells (CD31 × 100).