Primary cerebral neuroblastoma. A clinicopathological study of 35 cases.

A series of 35 primary cerebral neuroblastoma is reported. These rare tumours occur most often in children in the first half of the first decade. Grossly the tumors are often massive, discrete, lobular, firm and cystic. Histologically three variants, largely determined by the extent and distribution of the fibrous connective tissue stroma, are recognized: (1) a classical variant, which most resembles the peripheral neuroblastoma and is characterized by a high frequency of Homer Wright rosettes and a relatively high frequency of ganglionic differentiation; (2) a desmoplastic variant, which is characterized by an intense connective tissue stroma; and (3) a transitional variant, in which both the classical and the desmoplastic features may be present within the same case, either concurrently or consecutively. Both the desmoplastic and the transitional forms are less likely to exhibit differentiation to mature ganglion cells, but the importance of identifying the primitive cell elements as neuroblasts is emphasized. With rare exceptions, this can be established only by specific silver impregnations on frozen material. Occasionally the direction of growth may be largely leptomeningeal. Seven illustrative clinical histories with pathological correlations are described. The over-all clinical behaviour of these tumours is that of malignant neuroepithelial neoplasms, characterized by a high recurrence rate. Recurrence may, however, be a late development, in some cases occurring five or seven years after apparently successful surgical removal. The tumour shows shows a high incidence of metastatic spread, almost 40 per cent of the cases examined at autopsy having disseminated in the cerebrospinal pathways. Exceptionally, extraneural metastases may also develop. However, long post-operative survival occasionally occurs, and the subsequent clinical course is not always predictable in the individual case. The differential diagnosis is briefly discussed. The cellular nature of the tumour and its biological behaviour recall those of the cerebellar medulloblastoma. Post-operative radiation to the entire neuraxis should be considered for these neoplasms.