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Epstein-Barr virus (EBV)-associated smooth muscle tumors following solid organ transplantation are extremely rare, with only 12 cases reported in the literature thus far. The exact pathogenetic role of EBV infection in the oncogenesis of these soft tissue tumors in immunodeficient patients and the biologic behavior of such tumors is still unclear. We report a 26-year-old man in whom multiple smooth muscle tumors developed 36 to 51 months after heart transplantation. All tumors, two synchronous liver nodules, two subsequently occurring paravertebral tumors, and a single tumor in a vein at the left ankle were surgically resected. The tumor tissue was processed for routine histology and immunohistochemical (IHC) stains. Additionally, competitive polymerase-chain-reaction (PCR), reverse-transcriptase PCR (RT-PCR), as well as in situ hybridization (ISH) were used for EBV particle quantification and gene transcription analysis. The histologic features and immunohistochemical profiles were consistent with leiomyosarcoma in all tumor nodules. EBV infection was detected in >95% of tumor cell nuclei by EBER 1/2 ISH. Competitive PCR revealed 3105 EBV particles per milligram of tumor tissue. The EBV gene expression pattern analyzed by RT-PCR and IHC corresponded to the latency type III with specific expression of EBNA1, EBNA2, LMP1, and LMP2A genes. Under continuous antiviral therapy (famcyclovir) the patient currently shows no evidence of disease. Our data indicate that EBV infection plays a causal role in the development of smooth muscle tumors following organ transplantation. A latency type III, identical to EBV-associated posttransplant lymphoproliferative disorders, was identified and suggests a common pathogenetic mechanism in the development of these histogenetically distinct neoplasms. The fact that the patient currently shows no evidence of disease may be the result of the continuous administration of antiviral therapy because the soft tissue recurrences of the leiomyosarcoma occurred while the patient was not receiving antiviral prophylaxis.

We report an unusual case of multifocal leiomyosarcoma involving the thyroid gland, liver, and right lung in a child with congenital immunodeficiency disease. The smooth muscle nature of these neoplasms was confirmed by immunohistochemistry and electron microscopic studies. In situ hybridization showed large amounts of Epstein-Barr virus messenger RNA within the tumor cells. Although Epstein-Barr virus-associated smooth muscle tumors have been reported in children with AIDS and after organ transplantation, we are unaware of any case report in congenital immunodeficiency disease.

The occurrence of Epstein-Barr virus-associated smooth-muscle tumors in immunocompromised patients has been reported, particularly in the pediatric population. In posttransplantation tumors, the tissue of origin has been either donor or recipient. Mixed-genotype sarcomas within the same patient have not yet been reported. We describe the occurrence of multiple leiomyosarcomas of both donor (arising in the lung allograft) and recipient (arising in the host liver) origin in a 15-year-old boy 3 years after heart-lung transplantation. Analysis of premortem lung tumors demonstrated the presence of Epstein-Barr virus DNA. Despite decreasing immunosuppression and commencing acyclovir, the patient died of systemic Pseudomonas infection. Immunohistochemical analysis revealed that both lung and liver tumors were negative for the Epstein-Barr virus receptor (CD21), and suggests that Epstein-Barr virus entry into the cells was not via this receptor but via an alternate mechanism such as cell fusion.