Scanning electron microscopy of retinoblastoma

The surface morphology of two continuous cell lines of human retinoblastoma (Y79 and WERI-Rbl) and freshly removed retinoblastoma were studied by scanning electron microscopy (SEM). Commonly observed surface features included microvilli, lamellipodia, filopodia, and zeiotic blebs. A close similarity was seen between the surface morphology of established cell lines of retinoblastoma and that of fresh tumor. Smooth, sphere-like cells were present in both cultured and fresh retinoblastoma. Samples of cultured retinoblastoma cells showed rosettes on light and transmission electron microscopy and the scanning electron microscopic counterparts were observed. The surface characteristics of retinoblastoma were compared to human neuroblastoma and human medulloblastoma grown in tissue culture. Some distinctions in the characteristics were found. No rosettes were seen and the smooth, sphere-like cells were absent. Scanning electron microscopy can be a useful adjunct to light microscopy and transmission electron microscopy (TEM) in the differential diagnosis of small undifferentiated round cell tumors.