Definition of pleomorphism in English:



mass noun
  • The occurrence of more than one distinct form of a natural object, such as a crystalline substance, a virus, the cells in a tumour, or an organism at different stages of the life cycle.

    • ‘Vascular invasion, mitosis, and cell pleomorphism are not observed in cases of bronchiolitis obliterans organizing pneumonia.’
    • ‘Mitosis, size of tumour, necrosis and pleomorphism are thought to be prognostic factors for aggressiveness of solitary fibrous tumours.’
    • ‘Several histologic findings, including increased number and size of cells, greater nuclear pleomorphism, and increased mitotic activity, suggest a well-differentiated fibrosarcoma.’
    • ‘The spindle cells showed moderate nuclear pleomorphism and scattered mitotic figures.’
    • ‘Bizarre cells, nuclear pleomorphism, and mitotic figures were easily found.’


Mid 19th century from Greek pleiōn ‘more’ + morphē ‘form’ + -ism.