Sellar Dermoid Cyst Coexistence with Pituitary Adenoma/Pituitary Neuroendocrine Tumor.

[INTRODUCTION] Collision tumors are extremely rare in the sellar region, less than 1 to 2% of sellar masses. Intracranial dermoid cyst is a rare, benign, slow-growing lesion accounting for 0.04 to 0.7% of all intracranial tumors. Sellar dermoid cysts are extremely rare; from 1976 to 2024, there were only 59 records of sellar dermoid cyst published in the English language. Coexisting sellar dermoid cyst and pituitary adenoma have not been reported in the literature.

[CASE PRESENTATION] A 51-year-old man having medical history of left traumatic optic neuropathy and acute lymphoblastic leukemia posttreatment with complete remission in 2018 suffered from intermittent dizziness and occasional unsteady gait with deviation to the left side for more than 6 months prior to visiting our hospital. His brain magnetic resonance imaging disclosed a mass lesion in the sellar region with suprasellar extension, and his preoperative hormone study showed hypopituitarism. After a thorough preoperative evaluation, he underwent an endoscopic endonasal transsphenoidal approach with the removal of the lesion and skull base reconstruction. The lesion was pathologically diagnosed to be a dermoid cyst with coexisting pituitary adenoma/pituitary neuroendocrine tumor.

[CONCLUSION] To our best knowledge, this is probably the first report of sellar dermoid cyst with coexisting pituitary adenoma/pituitary neuroendocrine tumor.