Aggressive silent GH pituitary tumor resistant to multiple treatments, including temozolomide.

Temozolomide (TMZ) has been proposed as a therapeutic option in aggressive pituitary tumors. Among the published cases, GH expressing tumors were rare. We describe a patient with initially benign silent GH adenoma that transformed into an aggressive GH secreting tumor resistant to usual therapy. MGMT expression was high and the MGMT promoter was unmethylated. Before this aggressive course, patient received three cycles of TMZ; no response was observed. Four cases of GH aggressive tumor treated by TMZ have been reported. Response to TMZ was observed in one of these four patients. Predictive factors of failure of TMZ remain unclear.