Pleomorphism

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Related to Nuclear pleomorphism: hyperchromatism

pleomorphism

[‚plē·ō′mȯr‚fiz·əm]
(biology)
The occurrence of more than one distinct form of an organism in a single life cycle.
(crystallography)

Pleomorphism

 

an environmentally produced change in the incidence of disease and causes of death as well as in the properties of individual diseases, that is, nosologic entities (see NOSOLOGY).

During the 20th century, extensive immunization of populations and nationwide preventive measures in economically developed countries have eradicated many infectious diseases, for example, plague and poliomyelitis, and have sharply reduced infant mortality caused by infectious diseases. Changes in living conditions have reduced the incidence of diseases that stem from nutritional deficiency, for example, avitaminoses and iron-deficiency anemia. On the other hand, the incidence of injuries, tumors, and cardiovascular and viral diseases has increased.

New hereditary and occupational diseases have resulted from such environmental changes as those that accompany the growth of the chemical industry. Therapy-induced pleomorphism is a change in the clinical picture of a disease as a result of treatment. For example, the use of drugs has led to the disappearance of severe forms of thyrotoxicosis and anemia. Similarly, tuberculous meningitis, comas in diabetes mellitus, and acute pulmonary suppuration have become rare. In leukemia, tumor cells have disappeared from bone marrow because of the use of cytostatic agents, but they multiply in the nervous system and viscera. Undesirable side effects may follow medicinal treatment, and beyond a certain intensity these constitute a drug disease. The aftereffects of gastric or cardiac surgery, for example, can also give rise to disease.

Diseases that have received a new nosologic classification because of the growth of medical knowledge should not be considered examples of pleomorphism.

REFERENCES

Davydovskii, I. V. Patologicheskaia anatomiia i patogenez boleznei cheloveka, 3rd ed., vols. 1–2. Moscow, 1956–58.
Shul’tsev, G. P. “Terapevticheskii patomorfizm.” Klinicheskaia meditsina. 1973, no. 6.
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References in periodicals archive ?
Leiomyosarcomas contain frequent mitotic figures, nuclear pleomorphism, and nuclear hyper-chromatism.
Histologically, the tumour shows intersecting fascicles of spindle cells with cigar-shaped nuclei and eosinophilic cytoplasm without significant nuclear pleomorphism or tumour necrosis.
The neuroendocrine areas had an organoid appearance and were composed of cells larger than small cell carcinoma with marked nuclear pleomorphism and frequent mitotic activity (Figures 2 and 3).
Malignancy can be identified on histology by increased cellularity, nuclear pleomorphism, cellular atypia, necrosis, haemorrhage and 4 or more mitoses per 10 high-power microscopic fields.
Nevertheless, few studies have been directed to evaluate the nuclear size and its variability in the preneoplastic epithelium of PIN, although some authors have suggested that the cytologic atypia and nuclear pleomorphism were more remarkable in the basal layer in comparison with the apical or columnar stratum of PIN lesions (Epstein, 1994).
These cells had eosinophilic cytoplasm and lacked significant nuclear pleomorphism and mitosis.
The tumor was composed of spindle to epithelioid cells, arranged in a solid sheetlike or fascicular growth pattern, showing focal prominent nuclear pleomorphism and granular cytoplasm (Figure 2, B).
Enlarged vesicular nuclei with prominent nucleoli, spindling of tumor cells, high nuclear-to-cytoplasmic ratio, nuclear pleomorphism, appreciable mitotic activity, and tumor necrosis should be suspicious of malignant GCT.
9 This usually depends on the subjective assessment of the degree of keratinisation, cellular and nuclear pleomorphism, and mitotic activity.
The cells have little nuclear pleomorphism and low mitoses present.
Photomicrographs of HE stained sections show a renal cell carcinoma (RCC) with tumor cells arranged in nests separated by thin vascular septae (a; x200); high magnification shows marked nuclear pleomorphism (b; x400); areas of angiomyolipoma (AML) composed of spindled and small epithelioid cells (c; x200) with uniform round to oval nuclei are present (d; x400); at places the spindled cells originate from walls of abnormal blood vessels (e; x200).
However, other areas had much higher cellularity, with nuclear pleomorphism and scattered multinucleated giant cells.