mitochondrial anomalies
Mitochondrial dysfunction plays an important role in cell injury and apoptosis. In addition, various alterations in the number, size, and shape of mitochondria occur in some pathologic conditions.
For example, in cell hypertrophy and atrophy, there is an increase and decrease, respectively, in the number of mitochondria in cells. Mitochondria may assume extremely large and abnormal shapes (megamitochondria), as can be seen in the liver in alcoholic liver disease and in certain nutritional deficiencies.
Abnormalities of mitochondria are now recognized as the basis of many genetic diseases.
In certain inherited metabolic diseases of skeletal muscle, the mitochondrial myopathies, defects in mitochondrial metabolism are associated with increased numbers of mitochondria that are often unusually large, have abnormal cristae, and contain crystalloids.
In addition, certain benign tumors (oncocytomas) found in salivary glands, thyroid, parathyroids, and kidneys consist of cells (sometimes called "oncocytes") with abundant enlarged mitochondria, giving the cell a distinctly eosinophilic appearance.