Epstein-Barr virus-associated smooth muscle tumor-report of 3 tumors including 1 intracerebral case with a prominent intratumoral B-lymphocytic component and plasma cells.

Three Epstein-Barr virus-associated smooth muscle tumors (intracranial, endobronchial, and paraspinal) in 2 patients are presented. The patient with the intracranial tumor had no concurrent or previous manifestation of this neoplasm and was immunosuppressed because of a renal transplant. The other patient had AIDS and radiologic evidence of involvement of multiple other sites. Although mitotic activity was present, none of the tumors displayed any high-grade malignant histologic features. All tumors were strongly positive for smooth muscle actin and variably expressed h-caldesmon. Desmin was negative in all 3 tumors. The intracranial tumor was associated with prominent intracerebral edema and displayed, in addition to a prominent intratumoral T-cell component, a hitherto unreported component of prominent intratumoral B cells and plasma cells.