The signature feature of sparsely granulated growth hormone pituitary adenoma: the fibrous body

The patient is a middle-aged female with subtle signs of acromegaly.

Arrows point to the pale balls in this pituitary adenoma  which correspond to
fibrous bodies on CAM 5.2 immunohistochemistry

The signature feature of sparsely granulated GH adenomas is the finding of widespread, ball-like, cytoplasmic ‘fibrous bodies’ on CAM5.2  in >70% of cells.

CAM 5.2 immunohistochemistry