Catecholamine fluorescence and tissue culture morphology. Technics in the diagnosis of neuroblastoma.

Neuroblastoma is often confused histologically with other small round cell tumors such as Ewing's sarcoma, acute lymphocytic leukemia, lymphoma, and oat cell carcinoma, particularly at metastatic sites. Studies were performed to evaluate glyoxylic acid-induced catecholamine fluorescence as a rapid method for identifying neuroblastoma cells in biopsy specimens. The morphology of tumor explants in tissue culture was also evaluated for use as a diagnostic aid. Eighteen neuroblastomas were stained for catecholamines; 78% showed specific catecholamine fluorescence. Two ganglioneurons and a pheochromocytoma also showed positive catecholamine fluorescence. All 20 neuroblastomas placed in tissue culture demonstrated neurite outgrowth, a property that distinguishes neuroblastoma from other small round cell neoplasms. Seventeen nonneuroblastoma tumors displayed neither specific fluorescence nor neurite outgrowth. The ability of these two technics to identify neuroblastoma was compared with routine histology, urinary vanillylmandelic acid (VMA) spot tests, quantitative urinary VMA and catecholamine assays, and electron microscopy. Only electron microscopy was as sensitive as fluorescence and morphology in culture. The fluorescence method is rapid and simple and provides a valuable tumor marker when positive. Neurite outgrowth in cell culture and electron microscopy, although more time-consuming, were the most sensitive of all the diagnostic methods evaluated.