Clinicopathological and Molecular Profile of Sellar Neurocytoma.

Objective: To investigate the clinical features, imaging characteristics, and molecular profile of sellar neurocytoma (SN).

Methods: Clinical, imaging, and pathological features of 11 cases of SN were retrospectively analyzed. Electron microscopy was performed in 5 cases. Molecular features were detected in tumor tissue by RNA sequencing, quantitative polymerase chain reaction, and immunohistochemistry.

Results: The clinical features of SN patients showed a high incidence of hyponatremia (73%, 8/11), and the tumors tended to invade the lateral side of the saddle area from preoperative imaging analysis. The tumors had positive NeuN, synaptophysin, neurofilament, somatostatin receptor 2 (SSTR2) immunohistochemistry staining. Tumor transcriptomic analysis suggested a new LMCD1-AS1:GRM7-AS1 fusion gene event and increased expression of 10 hypothalamus-secreted hormones in SN. Fifteen differentially expressed genes were verified for quantitative polymerase chain reaction verification. SSTR2 has been verified by immunohistochemistry.

Conclusion: Hyponatremia is the dominant clinical features of SN. Preoperative imaging suggests that growth toward the dorsal region is the imaging feature of SN. SSTR2 expression and LMCD1-AS1:GRM7-AS1 fusion gene event expected to become a new molecular marker for SN. Somatostatin receptor ligand therapy may be a potential therapy for SN.