Correlations between clinical hormone change and pathological features of pituicytoma

Purpose: Pituicytoma is a rare low-grade glioma arising from the pituicytes of the posterior pituitary. To date, the clinical and pathological correlates of pituicytoma have not been investigated. This study was thus designed to examine the correlation between pituicytoma and the normal pituitary gland. Methods: The records of patients who underwent pituitary surgery at Chang Gung Memorial Hospital in Linkou, Taiwan between 2000 and 2016 were reviewed. Patients who received a pathological diagnosis of pituicytoma were included; however, those with inadequate specimens for pathological study were excluded. Clinical information, including patients’ presenting symptoms, serum hormone levels, neuroimages, and specimens, were collected. Hematoxylin and eosin stains and immunohistochemical (IHC) stains were performed for differential diagnosis. Results: Among the 1532 patients who underwent pituitary surgery, nine (0.59%) received a pathological diagnosis of pituicytoma. Two patients were excluded due to inadequate specimens. Among the seven remaining patients, six presented with hormone changes. The IHC stains revealed that pituicytoma has no secretory function; however, the resected pituitary glands showed positive results for hormone change. Coexisting pituicytoma and adrenocorticotropic hormone adenoma were identified in one patient with a diagnosis of Cushing disease. Conclusions: Pituicytoma revealed a negative endocrine secretory function through IHC staining. Additionally, pituicytoma is associated with hypersecretion of the pituitary gland both clinically and pathologically. Diagnosing pituicytoma before pathological confirmation is difficult because the tumour may present with hormone dysfunction. Therefore, IHC staining of specimens is useful to exclude the possibility of coexisting pituicytoma and pituitary adenoma.