The sellar and suprasellar region: A "hideaway" of rare lesions. Clinical aspects, imaging findings, surgical outcome and comparative analysis.

OBJECTIVE: Apart from the "common" lesions (e.g. pituitary adenomas, Rathke's cleft cysts, meningiomas and craniopharyngiomas), there is a plethora of rare tumors or tumor-mimicking lesions in the sellar and suprasellar region (SSR). Due to a lack of characteristic imaging features, there is a dilemma in distinguishing these rare lesions from the more "common" ones preoperatively. Consequently, both diagnosis and definition of surgical goals, as well as further treatment strategies continue to be challenging for all attending physicians. To replenish the scarce data on this issue, we analysed all patients with infrequent non-adenomatous pathologies in the SSR treated in our clinic, providing a database for further studies.
METHODS: A retrospective study was performed including 223 patients who were operated on lesions within the SSR at the Department of Neurosurgery, Hannover Medical School, between 2006 and 2014. The patients' charts were analysed with regard to the results of pre-/postoperative endocrinological and neuroophthalmological examinations. Preoperative T2WI were analysed with special focus on distinct growth patterns within four quadrants constituting the (supra-)sellar region. In this way, a comparative analysis between the diverse lesions regarding their clinical features, resectability and the final outcome was possible.
RESULTS: After exclusion of cases with "common" lesions, a collective of 20 patients with rare lesions within the SSR was obtained. The histopathological diagnosis revealed xanthogranulomas (n=6), metastatic tumors (n=5), colloid/epidermal cysts (n=3), pilocytic astrocytomas (n=2), and one case each of gangliocytoma, lymphocytic hypophysitis or concomitant germ cell tumor/rhabdomyosarcoma. In comparison to non-infiltrative lesions, those of infiltrative nature caused more frequently diplopia and deterioration of visual acuity (4 cases; p<0,05) that were less prone to improve postoperatively. Regarding growth pattern, metastatic tumors demonstrated main growth within the third quadrant with destructive remodelling of the dorsum sellae (p<0,05). While patients harbouring large lesions (>20mm) showed a significantly worse outcome regarding hormonal deficits (p=0,0313), the overall prognosis was heavily linked to the histopathological diagnosis.
CONCLUSION: The correlation of the subtle radiological findings demonstrated with the specific clinical features may facilitate the differential diagnosis of rare lesions of the SSR and aid in establishing an interdisciplinary diagnostic and therapeutic procedure for these lesions.