Dysplasia definition in medical literature
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Medical Definition of Dysplasia: General Concepts
Dysplasia in medical literature refers broadly to abnormal development or growth of cells, tissues, or organs. It is most commonly used to describe precancerous changes where there is an increase in immature or atypical cells, abnormal differentiation, and disordered tissue architecture. Dysplasia is considered a step between normal tissue and cancer, often indicating a higher risk for malignant transformation if left untreated 1237.
Dysplasia in Epithelial Tissues: Cellular and Histological Features
In epithelial tissues, such as the uterine cervix or gastrointestinal tract, dysplasia is characterized by an increased number of immature cells, abnormal cell differentiation, and architectural disorganization. These changes are visible under a microscope and may include features like abnormal nucleus-to-cytoplasm ratios, nuclear irregularities, and increased mitotic activity. Dysplasia is often graded as low or high grade, depending on the severity of these changes and the risk of progression to cancer 1237.
Dysplasia as a Precancerous Lesion
Dysplasia is widely recognized as a precancerous lesion, especially in organs like the cervix and gastrointestinal tract. It is defined as a neoplastic lesion limited to the epithelium, without invasion into deeper tissues. The World Health Organization (WHO) and Vienna classifications use a two-grade system (low and high grade) to describe the severity and potential for malignant transformation 23.
Cellular and Molecular Criteria in Dysplasia
Modern definitions of dysplasia also consider molecular and cell cycle abnormalities. Dysplastic cells often show unbalanced chromosome segregation, persistent genomic asymmetry, and aneuploidy (abnormal number of chromosomes). The frequency of abnormal mitoses and the degree of genomic alteration help distinguish between low-grade and high-grade dysplasia, providing insight into the lesion’s malignant potential 37.
Dysplasia in Bone and Connective Tissue
In bone, such as in fibrous dysplasia, the term describes a benign condition where normal bone is replaced by fibrous tissue, leading to bone pain, deformities, and fractures. This form of dysplasia is not precancerous but represents abnormal tissue development and can be associated with syndromes like McCune-Albright .
Dysplasia in the Hip: Lack of Consensus
For developmental dysplasia of the hip (DDH), the term refers to a spectrum of abnormal formation and alignment of the hip joint components. There is no single, universally accepted definition, and descriptions vary across morphological, clinical, and radiological perspectives. DDH is recognized as a developmental disorder, not necessarily precancerous, and definitions emphasize the abnormal development of the hip joint in infants and children 45.
Conclusion
Dysplasia in medical literature generally refers to abnormal cellular or tissue development, often with a risk of progression to cancer in epithelial tissues. The definition varies by organ system, with specific criteria for cellular, molecular, and structural abnormalities. While the term is most commonly associated with precancerous epithelial lesions, it is also used in non-cancerous contexts, such as bone and joint development, where it describes abnormal tissue formation rather than a direct cancer risk 1234567.
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