Pituitary Hemitransposition for the Resection of a Pilocytic Astrocytoma in a Middle Aged Man with Multiple Sclerosis

Background: Pilocytic astrocytomas are generally considered to be pediatric tumors. However, rarely, adults can present with them. The author discusses the case of 46-year-old male presenting with gynecomastia and a retrosellar mass with a history of multiple sclerosis and testicular cancer.

Case Discussion: The patient initially sought medical attention because of breast tenderness and gynecomastia. He had a prolactin level sent that was abnormal at 44.2 ng/mL. His MRI showed an irregular T2 hyperintense lesion without contrast enhancement in the retrosellar space. There was very mild mass effect on the posterior and dorsal aspect of the optic chiasm and widening of the hypothalamus. He had formal visual field testing. Because the mass had grown over 12 year period and because of the contact with the optic apparatus, surgery was indicated for diagnosis and resection. The patient underwent an endoscopic, endonasal, transtubercular, transsellar, and transclival approach with resection of the left sided posterior clinoid to access the lesion. Once the dura was opened over the sella face, sharp dissection allowed for a left sided pituitary hemitransposition which allowed for visualization of the mass, which was dark gray and gelatinous. The tumor was then resected entirely. The patient experienced diabetes insipidus intraoperatively. Postoperatively, he required exogenous administration of antidiuretic hormone. He returned to clinic with concern for a low-flow spinal fluid (CSF) leak and a head CT that was showing resolving pneumocephalus. As such, he was a candidate for lumbar drain placement for primary treatment of his CSF leak. His CSF leak and breast tenderness resolved with a normalized prolactin at 17.6 ng/mL.

Conclusion: The patient was thought to have a cystic craniopharyngioma or Rathke's cleft cyst but in fact he had an intra-axial tumor of the hypothalamus. Postoperatively, the patient's hormonal abnormalities resolved and he had a gross total resection. The endoscopic, endonasal approach with pituitary hemitransposition was an effective, minimally invasive approach that provided therapeutic and oncologic benefit.