EPSTEIN-BARR VIRUS-ASSOCIATED LEIOMYOSARCOMAS IN LIVER-TRANSPLANTATION RECIPIENTS - ORIGIN FROM EITHER DONOR OR RECIPIENT TISSUE

Background. Leiomyosarcoma, a mesenchymal malignancy with smooth muscl e differentiation, is extremely rare in children. Immunosuppression, d ue to either antirejection medication in organ transplantation recipie nts or human immunodeficiency virus infection (HIV), appears to consti tute a predisposition. Methods. Two cases of leiomyosarcoma in pediatr ic liver transplantation recipients were investigated and compared cli nically with respect to site of origin and course of the disease and p athologically by routine histology and electron microscopy, by forensi c DNA methodology for origin from donor or recipient tissue, and by EB ER-1 in situ hybridization for evidence of latent Epstein-Barr virus ( EBV) infection. Results. A 9-year-old male developed a high grade, poo rly differentiated leiomyosarcoma in his allografted liver 2 years aft er transplantation, and despite antineoplastic chemotherapy, he died o f metastatic disease, The genotype of his tumor indicated an origin fr om allografted tissue, A 12-year-old female had a low grade retroperit oneal leiomyosarcoma involving the superior mesenteric vein. After res ection, she remained disease free without chemotherapy. The genotype o f her tumor indicated an origin from native tissue. In both tumors, la tent EBV infection was documented. Conclusions. Neoplastic smooth musc le proliferation in immunosuppressed liver transplantation recipients is analogous to the more common posttransplantation lymphoproliferativ e disorder in involving transformation of either engrafted donor tissu e or recipient tissue elsewhere in the body, in displaying a wide spec trum of histologic differentiation, grade and clinical behavior, and i n exhibiting evidence of latent EBV infection.