SF-1 immunohistochemistry for detecting gonadotroph adenomas

Adenomas driven by the transcription factor SF-1, which are exclusively gonadotroph adenomas, are a common subtype encountered by the surgical pathologist. Traditionally, gonadotroph adenomas have been defined by positive immunostaining for luteinizing hormone (LH) and/or follicle stimulating hormone (FSH) with or without alpha-subunit (αSU). However, SF-1 alone can detect gonadotrophin adenomas. Further, the majority of previously classified "null cell" adenomas -- negative for all hormonal markers including LH, FSH and αSU -- are in fact positive for SF-1 and therefore better classified as gonadotroph adenomas.

A gonadotroph pituitary adenoma so classified based solely on SF-1 positivity