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.