PITUITARY GRANULOMA AND CHRONIC INFLAMMATION OF HYPOPHYSIS - CLINICALAND IMMUNOHISTOCHEMICAL STUDIES

We describe five patients with chronic inflammation of the hypophysis including three pituitary granulomas of unknown aetiology. In contrast to the previously reported cases, the involvement of neurohypophysis or hypothalamus was a distinct clinical feature in these patients. Imp airment of anterior pituitary function was less prominent, while poly- uria and polydipsia occurred in all cases. Enlargement of the sella tu rcica was absent in three and slight in two cases. CT scan and MR imag es demonstrated a contrast-enhanced .sellar mass in all patients; abno rmally thickened pituitary stalk and infundibulum with contrast-enhanc ement was observed in four. The fibrous tissues were removed by the tr anssphenoidal approach in four patients, and by the subfrontal approac h in one case. In all patients, the endocrinological dysfunction was p rolonged. No increase in the size of the remaining pituitary mass was demonstrated on repeated MR images in any of the patients. On histolog ical examination, granulomatous formation was present in three samples , and multinucleated Langhans' giant cells were seen in one. The epith elioid cells and multinucleated giant cells constituting the granuloma s were positive for anti-macrophage antibody. No firm laboratory or hi stological evidence was obtained supporting the presence of systemic d isease leading to granulomas. In the other two cases, the pituitary le sions were composed of chronic inflammation tissue, and serum antipitu itary antibodies were present in a patient with concurrent Hashimoto's thyroiditis. Our experiences with chronic inflammation of the hypophy sis indicate that these patients are best managed by histological conf irmation of the lesion followed by adequate hormonal replacement. Base d on our findings and those reported in the literature, we propose tha t patients with granulomatous hypophysitis or chronic inflammation of the hypophysis be managed as follows: When an underlying disease is de tected, the patient should begin to receive conservative treatment for the causative disease plus hormonal replacement therapy, as necessary . However, when visual disturbance is progressive and uncontrollable b y conservative means, surgical decompression of the chiasma is require d. If the pathogenesis of the pituitary lesion cannot be identified, s urgical exploration is essential for a precise pathological diagnosis. When a granulomatous or chronic inflammatory process is evident intra -operatively, partial removal or biopsy are recommended. Radical resec tion of fibrous and adhesive tissue with infundibular impairment will lead not only to exacerbation of the pre-existing anterior- and/or pos terior pituitary dysfunction, but also to grave hypothalamic injury.