Spindle cell oncocytoma of the adenohypophysis: a case report illustrating its natural history with 8-year observation and a review of the literature.

Spindle cell oncocytoma of the adenohypophysis is a rare tumor classified by the World Health Organization as benign with no malignant features. Recent publications have questioned its identity as a benign tumor, as six postsurgical recurrences of spindle cell oncocytoma (SCO) have been reported. This case is the first to illustrate the natural history of the disease due to delayed intervention, as the tumor showed virtually no growth. This is an important illustrative case to highlight that urgent surgery may not be required and conservative close serial surveillance MRI may be a valid management option.