Aspiration and exfoliative cytology, including ultrastructure, of a malignant granular-cell tumor

The cytopathologic features of a malignant granular cell tumor in both exfoliative and aspiration cytopreparations included isolated cells with low nuclear-cytoplasmic ratios and abundant, diffusely granular cytoplasm. Transmission electron microscopy revealed the diagnostic secondary lysosomes in the neoplastic cells.