Behind the Sella: A Rare Case of Pituicytoma Mimicking a Pituitary Adenoma

BACKGROUND Pituicytoma is a rare central nervous system (CNS) World Health Organization (WHO) grade I glioma originating from pituicytes, the specialized glial cells of the neurohypophysis or infundibulum. It accounts for less than 0.1% of all sellar and suprasellar masses and often presents a diagnostic challenge because of its clinical and radiological resemblance to other pituitary lesions. CASE REPORT A 48-year-old man was admitted to the endocrinology clinic because of clinical symptoms of hypogonadism, headaches, and visual field defects. Hormonal evaluation revealed hypogonadotropic hypogonadism and hyperprolactinemia. Magnetic resonance imaging (MRI) demonstrated a sellar-suprasellar mass, initially suggestive of prolactinoma. Lack of response to initial hormone replacement therapy, progressive tumor enlargement, and worsening visual impairment, prompted surgical resection via a right-temporal craniotomy. Histopathological and immunohistochemical examination established the diagnosis of pituicytoma (CNS WHO Grade 1). The postoperative course was complicated by transient cognitive impairment and endocrine deficiencies requiring long-term hormonal replacement therapy. We also review the epidemiology, clinical presentation, and current therapeutic approaches for this uncommon tumor. CONCLUSIONS Pituicytoma is a rare benign tumor that may closely mimic pituitary adenoma, both clinically and radiologically. Clinical manifestations are non-specific and primarily reflect tumor size and local extension. MRI findings are not pathognomic, making histopathological confirmation essential. Surgical resection remains the treatment of choice, whereas radiotherapy may be considered after subtotal resection. The case underscores the importance of recognizing hyperprolactinemia secondary to pituitary stalk compression, careful endocrine interpretation, individualized surgical planning, and prolonged multidisciplinary follow-up, given the uncertain long-term prognosis and potential endocrine sequelae.