A 44-year-old male suffered from an inactive pituitary adenoma measuring 20mm in computed tomography (CT) scan and nuclear magnetic resonance tomography (NMR). The tumor was surgically resected via the transnasal-transsphenoidal route. Surgical specimens revealed a typical, sparsely granulated adrenocorticotropic hormone (ACTH) cell adenoma, but also a granulomatous inflammation mostly in the periphery of the tumor, corresponding to a granulomatous hypophysitis. This coincidence appears to be unique and has yet not been described in the literature. Therefore, the clinical data and the pathohistologic and ultrastructural findings are presented here.