Collision sellar lesions: coexistence of pituitary adenoma and Rathke cleft cyst-a single-center experience.

Collision sellar lesions represent the coexistence of distinct histopathological lesions found in the sella turcica. They are uncommon entities and have mainly been reported as pituitary adenoma (PA) associated to Rathke cleft cyst (RCC). Pre- and perioperative diagnosis is difficult, since most of the cases appear clinically, radiologically, and macroscopically as solitary cystic sellar lesion. A retrospective study of histological reports from patients operated for PA from 2013 to 2018 in a single neurosurgery reference center was performed. Patients who also exhibited RCC in the histological sections were included. Clinical and biochemical data were collected from medical files. MRI scans and histopathological slides were also reviewed. Among 554 PA, five patients (0.9%) presented the association of PA and RCC. At diagnosis, patients had median age of 60 years (33-78) with, at least, one pituitary dysfunction, and visual field loss and/or headache. There was a female predominance (n = 3). All patients had nonfunctioning PA. MRI studies showed a predominantly cystic lesion and were unable to distinguish both lesions. The definitive diagnosis was made by histopathology. The association of PA and RCC is extremely rare. On MRI, they appear as a solid-cystic or cystic sellar tumors. RCC can rupture causing granulomatous reaction with cholesterol crystal formation, which can be mistaken for craniopharyngiomas during surgery. Therefore, collision sellar lesion must be included in the differential diagnosis of cystic sellar lesions. The definitive diagnosis is made by histological study.