Isolated Intracranial Rosai-Dorfman Disease Mimicking Sellar Pituitary Adenoma: a case report and literature review.

[BACKGROUND] Rosai-Dorfman disease (RDD), also known as sinus histiocytosis with massive lymphadenopathy (SHML), is an extremely rare non-Langerhans cell histiocytosis. The diagnostic histiocytes in RDD are characterized by the immunophenotypic markers S100 (+), CD68 (+), and CD1a (-) (Abla O, Blood 131: 2877, 2018),(Emile JF, Blood 127: 2672, 2016) , and exhibit phagocytosis with varying frequency. To our knowledge, this is the first reported case of isolated Intracranial Rosai-Dorfman Disease Mimicking Sellar Pituitary Adenoma, with peripheral facial paralysis as the initial presentation. By integrating imaging findings, histopathological features, and treatment response, we explore the diagnostic challenges and management strategies, aiming to enhance clinicians' awareness of RDD involving the pituitary.

[CASE PRESENTATION] We report the case of a 50-year-old Han Chinese female who presented with left-side peripheral facial paralysis and tender enlargement of the left cervical lymph nodes. Pituitary MRI revealed an intrasellar mass with homogeneous enhancement, initially diagnosed as a pituitary adenoma. The patient underwent transnasal transsphenoidal endoscopic resection of the pituitary adenoma. But histopathology and immunohistochemistry (S100+, CD68+, CD1a-) confirmed the diagnosis of RDD. Postoperatively, the facial paralysis improved, Unfortunately, 6 months follow-up MRI showed tumor recurrence.

[CONCLUSION] The clinical manifestations of intrasellar RDD are insidious and lack specificity, making it easy to confuse with common pituitary space-occupying lesions. Currently, surgical resection remains the gold standard for definitive diagnosis and is the primary therapeutic intervention, long-term follow-up is crucial for monitoring recurrence.