Peripheral neuroectodermal tumour (neuroepithelioma) of the thoracopulmonary region: light and electron microscopic cytology.

We describe a case of peripheral neuroectodermal tumour of the thoracopulmonary region diagnosed by fine needle aspiration cytology. Light microscope examination revealed numerous small tumour cells arranged in large irregular aggregates occasionally delimiting empty vascular-type spaces or forming rosette-like structures. Cytologically the tumour cells showed a marked degree of nuclear anaplasia, scanty cytoplasm and long thin cytoplasmic processes. Electron microscopy revealed cells with characteristics of neuroectodermal differentiation.