Kidney Graft Leiomyosarcoma: A Case Report

Kidney transplant (KT) recipients have a higher incidence of malignancy than the general population. Smooth muscle tumors (SMT), including leiomyosarcoma, are rare in kidney transplant recipients, and most cases are associated with Epstein-Barr virus (EBV) infection.

A 57-year-old man received a deceased donor kidney transplant at the age of 53 years, with 5 human leukocyte antigen (HLA) mismatches. Before the transplantation, the patient was IgG positive for EBV viral capsid antigen (VCA), negative for IgM EBV VCA, and also negative for IgG EBV nuclear antigen (EBNA), suggesting a prior EBV infection. He received immunosuppressive induction with basiliximab, and maintenance with tacrolimus, mycophenolate mofetil, and prednisolone. Two years after transplantation, he had an acute cellular rejection episode treated with methylprednisolone. An increased graft size was found 4 years after transplantation. A computed tomographic scan showed 3 solid tumors involving the renal graft with extension to the perinephric fat; no secondary localizations were found. A nephrectomy of the graft was performed. The histologic diagnosis was a high-grade leiomyosarcoma. In situ hybridization for EBV was negative. Nine months after nephrectomy, local recurrence was diagnosed. The surgical approach was unsuccessful, and the patient died after a brief period.

Kidney leiomyosarcoma is a very rare clinical condition. Most of these neoplasms that arise in transplanted recipients are associated with EBV in tumor tissue. Only one case of renal graft leiomyosarcoma without EBV RNA in the tumor has been previously reported.