[A clinicopathological and prognostic study of 22 cases central neurocytoma]

To investigate the clinicopathological features and prognosis of 22 cases of central neurocytoma (CNC), representing 0.48% of a series of 4 528 patients undergoing biopsy for central nervous system tumors.

The histopathological, ultrastructral, immunohistochemical and clinical features of CNC were studied by electron microscopic examination and immunohistochemical stain for Synaptophysin (Syn), neuron special enolase (NSE), Leu-7, glial fibrillary acid protein (GFAP), MBP and proliferating cell nuclear antigen (PCNA).

The age of the cases ranged from 4 to 44 (average 27.9 years) with all tumors localized in the ventricles. In the 18 patients followed up, 14 were alive for 8 months to 14 years and 11 months after the operation, and 4 died. The average survival period was 70.7 months. Histologically, the tumor in all 22 cases had the oligodendroglioma-like pattern with honeycomb appearance and cell-free islands of eosinophilic matrix. Cellular anaplasia, mitosis and necrotic areas were rarely seen in the tumors. Immunohistochemical study demonstrated strong positivity for Syn, NSE and Leu-7, and negative for GFAP and MBP. Ultrastructural features showed presence of round tumor cells with abundant cell processes containing microtubules, neurosecretory granules, clear vesicles and lysosome-like structures.

The differential diagnosis between CNC and oligodendroglioma could not be established by routine light microscopy. The importance of immunohistochemical and electron microscopic studies for making a correct diagnosis is emphasized. The prognosis of patients is usually favorable, even if the tumor was resected subtotally. The relationship between the presence of anaplastic histological features in CNC and patient outcome remains unclear.