The occurrence of more than one distinct form of a natural object, such as a crystalline substance, a virus, the cells in a tumor, or an organism at different stages of the life cycle.
- ‘Mitosis, size of tumour, necrosis and pleomorphism are thought to be prognostic factors for aggressiveness of solitary fibrous tumours.’
- ‘The spindle cells showed moderate nuclear pleomorphism and scattered mitotic figures.’
- ‘Several histologic findings, including increased number and size of cells, greater nuclear pleomorphism, and increased mitotic activity, suggest a well-differentiated fibrosarcoma.’
- ‘Bizarre cells, nuclear pleomorphism, and mitotic figures were easily found.’
- ‘Vascular invasion, mitosis, and cell pleomorphism are not observed in cases of bronchiolitis obliterans organizing pneumonia.’
Mid 19th century: from Greek pleiōn more + morphē form + -ism.