In two patients with hip replacement, the pelvic lymph nodes were resected during prostatectomy for carcinoma. The striking histiocytosis was present in lymph nodes. The cytoplasm of histiocytes was bulky, granular, PAS positive, with KP1, lysozyme and alfa-1-antitrypsin positivity. In polarized light microscopy, the birefringent, needle-like particles corresponding to polyethylene or polyester respectively were seen. Those changes are characteristic for reactive lymphadenopathy in regional lymph nodes following joint endoprosthesis.