Fig. 15.

Diagnostic algorithm for pathological and etiological classification of pituitary inflammation. Starting point of the algorithm is the histological evidence of pituitary inflammation. End points are the etiological hypophysitis classification combined with the degree of diagnostic certainty. The preceding term “probable” should prompt further multidisciplinary diagnostic work-up in order to clarify the diagnosis. If new relevant aspects arise from other disciplines, the algorithm returns to the starting point. The final diagnosis unifies the degree of diagnostic certainty (certain/probable/indeterminate), etiology (primary/secondary), and pathological classification (lymphocytic/plasmacytic/granulomatous/xanthomatous/…). *The recognition of necrotizing primary hypophysitis as a distinct entity is questionable. Detection of pituitary necrosis should prompt characterization of the inflammatory infiltrate found in the intact pituitary tissue. Vascular pathogenesis (pituitary apoplexy) or tumor necrosis should be considered