Epstein-Barr virus-associated smooth muscle tumor of the cavernous sinus: a delayed complication of allogenic peripheral blood stem cell transplantation: case report.

Epstein-Barr virus (EBV)-associated smooth muscle tumors (SMTs) have recently been associated with primary and secondary immunodeficiencies. They are broadly divided into 3 subgroups: HIV-related, posttransplant, and congenital immunodeficiency. Subsequent to organ transplantation and acquired immunosuppression, a few cases of EBV-associated SMTs have been described in the liver, respiratory tract, and gastrointestinal system. To the authors' knowledge, intracranial involvement after peripheral blood stem cell transplantation has never been reported previously. The authors describe the case of a 65-year-old woman who presented with recent-onset painful ophthalmoplegia. She had a prior history of acute myelogenous leukemia requiring allogenic peripheral blood stem cell transplantation 2 years earlier, but she was in a remission phase. Imaging revealed a T1/T2 isointense, homogeneously enhancing lesion of the left cavernous sinus. A presumptive diagnosis of Tolosa-Hunt syndrome was made, and she was treated with steroids; however, her symptoms progressed quickly and repeat imaging revealed that the lesion was growing. To rule out leukemic deposits, a minimally invasive lateral orbitotomy extradural transcavernous approach was performed for biopsy sampling and debulking of the lesion. The biopsied tumor tissue was found to be infiltrative, grayish, firm, and moderately vascular. The final pathology results indicated an EBV-associated SMT of the cavernous sinus. Subsequently, the patient's steroid treatment was stopped and she had obtained partial symptomatic relief at her last follow-up visit, 3 months after surgery. EBV-associated SMT should be included in the differential diagnosis for intracranial and dural-based central nervous system lesions, especially in immunocompromised patients. Paradoxical response to steroids with worsening of symptoms is a hallmark of EBV-associated SMTs.