What identifying feature is often observed in malignant cells?

Malignant cells are typically characterized by an abnormal appearance, one of the most notable features being enlarged nuclei with irregular contours. This abnormality occurs due to changes in the genetic material and an increase in the nuclear-cytoplasmic ratio, often seen as the nucleus becomes larger relative to the overall cell size. The irregular shape of the nuclei is indicative of the chaotic growth patterns and genetic instability present in cancerous cells. In contrast, benign cells usually have more uniform nuclei with smoother, well-defined contours, maintaining a normal nuclear size and ratio relative to the cytoplasm. The presence of enlarged and irregular nuclei in malignant cells serves as a critical diagnostic marker in cytology, helping pathologists and medical professionals identify and evaluate cancerous tissues.