Pituitary Stalk Lesions - Single Center Long Term Observation

Background & Methods: Pituitary stalk lesions (PSL) are various changes located in the pituitary infundibulum. The underlying pathology and exact diagnosis are difficult to establish due to their unique anatomical locus. A retrospective observational analysis of 60 adult patients (34W/26M) with pituitary lesions was performed. The mean age of diagnosis was 33.8 years (SD 23.7). The etiologies were divided into 3 groups (congenital, inflammatory, neoplastic), classified as exact, probable or unknown and characterized hormonally. Aim: To present the etiological spectrum of pituitary stalk lesions and their clinical and hormonal characteristics on the basis of long term observation in the pediatric/adult endocrinology departments of our university. Results: The most common causes of PSL were neoplasms (20/60, 33.3%, 14W/6M); congenital malformations were detected in 17/60 (28.3%, 6W/11M), while inflammatory etiology was found in 15/60 (25.0%, 9W/6M) of patients. The exact diagnosis was established in 26/60 (43.3%) cases (16 congenital malformations, 6 adenomas, 1 pituitary cancer, 1 craniopharyngioma, 1 germinoma and 1 lymphocytic hypophysitis [LH]). The probable cause was suggested in 26/60 patients (43.3%) - 10 with the suspicion of LH, 4 with histiocytosis, 3 with a metastatic tumor from a disseminated cancer, 3 craniopharyngiomas, 1 posterior pituitary lobe ectopy, 1 prolactinoma, 1 granular cell tumor, 2 adenomas and 1 pituicytoma. The origin of 8/60 PSL (13.3%) remains unknown. During hormonal assessment the most common insufficiency concerned the gonadal axis found in 29/60 (48.3%) of patients, followed by thyroid (26/60, 43.4%), somatotropic (21/60, 35.0%) and adrenal axis (20/60, 33.3%) insufficiencies. Hyperprolactinemia was detected in 20/60 (33.3%) of patients, while diabetes insipidus was confirmed in 15/60 (25%) of cases. 45 patients presented at least 1 hormonal deficit, some of them were transient. In clinical aspect, symptoms associated with hormonal deficits led to the initiation of diagnostic work-up in 29 patients (48.3%; including 15 patients (25.0%) with growth retardation). Neurological symptoms such as headaches, visual disturbances and seizures were seen in 13 patients (21.7%). Polydipsia and polyuria were the primary presentation in 11 cases (18.3%), while 5 cases (8.3%) had a clinical manifestation of hormone overproduction. Incidental diagnosis was seen in 2 female patients (3.3%). Conclusions: The diagnosis, management and treatment of the pituitary stalk lesions remains challenging. Difficulties in establishing the exact diagnosis might also be related to the non-specific, transient characteristics of the symptoms and hormonal insufficiencies. Long term observations might help better the understanding of the disease and result in improvement of management.