Primary Intraventricular Leiomyoma in an Immunocompetent Patient: First Case Report and Review of the Literature.

BACKGROUND Primary intracranial leiomyoma is an extremely rare occurrence of a low-grade mesenchymal tumor characterized by a proliferation of smooth muscle cells. When present, these lesions predominantly occur in immunocompromised patients in the setting of infection or transplant and have not been known to involve the ventricular system of the brain. In this report, we describe a case of primary leiomyoma of the lateral ventricle in an immunocompetent patient. CASE DESCRIPTION A 30-year-old man with no medical history presented with progressive diplopia and occipital headaches. Magnetic resonance imaging of the brain revealed a homogenously enhancing mass of the left lateral ventricle with associated cerebral edema. The patient underwent interhemispheric transcallosal craniotomy for resection for symptom alleviation and surgical diagnosis. Histopathology and immunohistochemistry was subsequently consistent with that of leiomyoma. Genetic probing for Epstein-Barr virus was negative. Computed tomography of the chest and abdomen failed to uncover a primary tumor. The patient did well postoperatively and was discharged 3 days after resection. At a two-and-a-half year follow-up, there continued to be no radiologic or clinical evidence of recurrence. CONCLUSIONS To date and to our knowledge, there are fewer than 25 reported cases of primary intracranial leiomyoma, with only 13 occurring in immunocompetent individuals. We believe this is the first report of this tumor type occurring within the ventricular system of the brain. As such, leiomyoma should be considered as a rare etiology in the differential diagnosis of intraventricular lesions.