A Case Series of Stereotactic Biopsy of Brainstem Lesions through the Transfrontal Approach.

 Brainstem lesions may be unresectable or unapproachable. Regardless, the histopathological diagnosis is fundamental to determine the most appropriate treatment. We present our experience with transfrontal stereotactic biopsy technique for brainstem lesions as a safe and effective surgical route even when contralateral transhemispheric approach is required for preservation of eloquent tissue.  Twenty-five patients underwent surgery by transfrontal approach. Medical records were reviewed for establishing the number of patients who had postoperative histopathological diagnosis and postoperative complications. Twenty-four patients (18 adults and 7 children) had histopathological diagnosis. There were 18 astrocytomas documented, of which 12 were high grade and 6 low grade. The other diagnoses included viral encephalitis, post-renal transplant lymphoproliferative disorder, nonspecific chronic inflammation, Langerhans cell histiocytosis, and two metastases. No case was hindered by cerebrospinal fluid loss or ventricular entry. Complications included a case of mesencephalic hemorrhage with upper limb monoparesis and a case of a partially compromised third cranial nerve in another patient without associated bleeding.  Stereotactic biopsy of brainstem lesions by transfrontal ipsilateral or transfrontal transhemispheric contralateral approaches is a safe and effective surgical approach in achieving a histopathological diagnosis in both pediatric and adult populations.