When a Sellar Mass Is Not a Pituitary Adenoma: A Literature Review and Lessons from a Case of Pituicytoma

Background: Pituicytomas are rare, low-grade gliomas arising from pituicytes in the posterior pituitary or infundibulum. Due to its rarity and nonspecific clinical and radiological characteristics, it is frequently misdiagnosed as pituitary adenomas or other sellar tumors. Aims: To present an overview of pituicytoma, including clinical presentation, radiological and histopathological characteristics, differential diagnosis and treatment strategies, illustrated by a case report. Methods: A literature review was conducted to contextualize our patient with a sellar tumor, and to highlight key diagnostic and therapeutic considerations. Results/Case report: A 12-year-old boy presented with visual disturbances. MRI revealed a well-defined contrast-enhancing sellar mass, and the patient underwent transsphenoidal surgery. The diagnosis was assumed to be a nonfunctioning pituitary adenoma (NFPA). Two years later a residual tumor was treated with proton irradiation. Six years after the radiotherapy, the patient had epistaxis. Imaging showed a tumor in the sphenoidale sinus, which was surgically resected. The tumor had histopathological features of pituicytoma and immunoreactivity for TTF-1 and S100. The tissue from the first operation was reviewed, showing more characteristics with pituicytoma than NFPA, leading to re-definition of the initial diagnosis. Follow-up has been without any signs of residual tumor. Conclusion: Our case and literature review emphasize the importance of considering pituicytoma in the differential diagnosis among sellar lesions. The diagnosis relies on a combination of preoperative imaging, intraoperative findings and histopathology. Pituitary surgery is the first-line treatment, and the outcome is generally good. Increased awareness of pituicytomas is necessary to improve preoperative diagnostic accuracy and guide appropriate management.