Skull base angiomatous leiomyoma: a case report and review of literature.

Leiomyomas, benign neoplasms of mesenchymal origin, are common in gastrointestinal and genitourinary tracts. They are comprised of well-differentiated smooth muscle cells with few mitotic figures. Leiomyomas should not exhibit metastatic potential, though metastasis has been reported. Primary intracranial lesions remain rare. Only 4 cases have been reported in immunocompetent patients. Here we report an intracranial leiomyoma in an immunocompetent patient. A 60 year-old woman with unremarkable past medical history presented with a right sixth nerve palsy. On examination, there was a right sixth nerve palsy with numbness over the right V2 and V3 areas. CT scan showed a well-defined lesion within the right middle cranial fossa adjacent to the cavernous sinus with bony remodelling of the lateral wall of the sphenoid sinus and greater wing of the right sphenoid. MRI showed extra axial mass lesion arising from the right Meckel´s cave/cavernous sinus. The lesion was T2 hyperintense and T1 isointense. Homogenously enhancing centrally with little enhancement peripherally. CT CAP showed no primary lesions. Differential diagnosis at that stage was between meningioma, schwannoma or metastasis. The patient underwent craniotomy and debulking of tumour. Histological analysis confirmed leiomyoma. Post-operative MRI showed residual enhancement in the region of Meckel's cave. As residual tumour was significant, the patient underwent STRS. Further MRI at 1 year showed regression of the tumour. Majority of intracranial leiomyomas are discovered in immunocompromised patients incidentally. Histology reveals spindle shaped cells with blunt ends and few mitotic figures. The best treatment option to date for primary intracranial leiomyomas remains surgical gross total resection without adjuvant radiation therapy. Intracranial leiomyoma transitioning to leiomyosarcoma post radiotherapy has been reported before and therefore follow up with serial imaging is warranted.