Significance of flower pot cells in effusion cytology

Cells with long polar hair‐like processes referred to as ‘flower pot cells’ are a rare but beautiful morphological feature observed in effusions of diverse etiologies. This report describes these cells in effusions seen in ovarian borderline serous tumours, malignant mesothelioma and in reactive mesothelial cells with or without accompanying malignant cells. These processes were better appreciated in air‐dried May‐Grunwald‐Giemsa stained smears.