Coexisting Non-functioning Pituitary Macroadenoma and Sellar-Suprasellar Lipoma: A Case Report and Literature Review

Intracranial lipomas are benign tumors that may occasionally be found in the suprasellar cistern while pituitary adenomas are far more common brain tumors. Pituitary adenomas may rarely coexist with other intracranial tumors in the sellar-suprasellar region. We share a unique case of a patient with coexisting non-functioning pituitary adenoma and sellar-suprasellar lipoma presenting with blurring of vision. We report a 55-year-old male presenting with a two-year history of blurring of vision with findings of a 2.7 x 3.0 x 3.2 cm homogeneously enhancing lobulated isointense mass on the sellar-suprasellar region. Hormonal workups revealed low cortisol and mildly elevated prolactin. He initially underwent endonasal transsphenoidal excision of the tumor which revealed to be a lipoma on histopathology. Due to minimal improvement of vision from the subtotal excision, he underwent repeat surgery through the transcranial approach which in turn showed a pituitary adenoma. The co-occurrence of two sellar-suprasellar tumors with different histology is rare, as most of the evidence is based on only a handful of case series. Intracranial lipomas result from persistence and abnormal differentiation of the meninx primitiva during the development of the subarachnoid cisterns. On the other hand, pituitary tumorigenesis is still largely unclear but appears to involve multiple tumor suppressor genes, oncogenes, cell cycle deregulation factors, and miRNAs. Given the differing pathogenesis of each tumor type, the coexistence may only be coincidental. The best surgical approach in this situation is unknown but the focus is on complete excision of the adenoma.