Abstract
Epstein-Barr virus associated smooth muscle tumors (EBV-SMT) are rare neoplasms that can occur in various anatomical locations. They mainly affect immunocompromised patients, and their clinical presentation is variable depending on size and organ involvement. They can pose diagnostic challenges, therefore if they are not considered in the differential diagnosis, they can be definitely misdiagnosed. Synchronous and multifocal involvement has been reported. Although malignant behavior maybe rarely seen; most behave in a benign fashion with favorable clinical outcome. We herein report an unusual case of synchronous EBV-SMT that occurred in the lung and liver in a 44-year-old female patient 7 years after renal transplantation. Both lesions were histologically examined revealing benign appearing spindle cell neoplasm that was positive on immunohistochemical staining for smooth muscle actin, desmin, and caldesmon with strong nuclear staining for EBV RNA by in situ hybridization. A brief pertinent literature review and discussion of EBV-SMT pathogenesis is offered. Saudi Med J 2012; Vol. 33 (9): 1010-1013