POSTARTHROPLASTY HISTIOCYTIC LYMPHADENOPATHY IN GYNECOLOGIC ONCOLOGY PATIENTS - A BENIGN REACTIVE PROCESS THAT CLINICALLY MAY BE MISTAKEN FOR CANCER

BACKGROUND. A distinctive histiocytosis occurs in the regional drainin g lymph nodes after large joint replacements, resulting in lymphadenop athy that may mimic cancer both grossly and microscopically. Postarthr oplasty histiocytic lymphadenopathy has most often been observed in ma les during surgery for prostate cancer. METHODS. The authors present t hree examples of postarthroplasty histiocytic lymphadenopathy that occ urred in gynecologic oncology patients. We studied the clinical, histo logic, and immunohistochemical features of all three cases and the ult rastructure of one of them. RESULTS. Most involved lymph nodes were en larged, but histiocytosis was also seen in normal sized lymph nodes. M icroscopically, histiocytes with abundant granular cytoplasm were pres ent in the lymph node parenchyma, and, to a lesser extent, in the sinu ses. Normal lymph node architecture was variably effaced and the histi ocytic infiltrate extended focally into the perinodal tissue. Small, b lack metal particles were present in the histiocytes in every case. Bi refringent polyethylene particles were a prominent finding in all thre e cases as confirmed by positive modified oil red O staining, and, in one case, by electron microscopy. The histiocytes were strongly immuno reactive for CD68, but immunostains for S100 protein, MAC 387, and cyt okeratin were negative. CONCLUSIONS. Enlargement of the lymph nodes in cancer patients who have had large joint replacements may be due to a benign histiocytosis rather than to metastatic cancer. The histologic features of the lymphadenopathy are distinctive and recognizable in r outine histologic preparations. Polyethylene wear particles shed from joint prostheses are the most common substances in the histiocytes and are the most likely cause of the histiocytosis. (C) 1996 American Can cer Society.