Necrosis distinguishing features

Protozoa usually can be identified in tissue sections stained with hematoxylin and eosin or Giemsa stain however, because of the small size of the organisms and the subtle distinguishing features, an unequivocal diagnosis cannot always be made. The role of IHC in the detection of protozoal infections has been particularly valuable in cases in which the morphology of the parasite is distorted by tissue necrosis or autolysis. In addition, in immunocompromised patients, toxoplasmosis can have an unusual disseminated presentation with numerous tachyzoites without bradyzoites (Fig. 

Various syndromes associated with hypereosinophilia involve skeletal muscle. There is a rare form of polymyositis which is characterized by this feature (defined as exceeding 1,500 eosinophils/mm for at least six months). Clinical presentation includes skin changes, heart and lung involvement, and peripheral neuropathy as well as proximal myopathy. The condition must be distinguished from trichinosis and other parasitic infections associated with hypereosinophilia. Muscle biopsy findings are interstitial and perivascular infiltrates in which eosinophils predominate but are accompanied by lymphocytes and plasma cells, and occasional muscle fiber necrosis. Fascitis may also be associated with hypereosinophilia (Shulman s syndrome). This condition is characterized by painful swelling of skin and soft tissues of trunk and extremities and weakness of limb muscles. Biopsy of muscle... 

Neuronopathy. Neuronopathy refers to generalized damage to nerve cells, with the primary damage occurring at the nerve cell body. Axonal and dendritic processes die secondarily in response to loss of the cell body. Like other cells in the body, neurons die by one of two processes distinguished by their morphological and molecular features apoptosis and necrosis. (This division is overly simplistic there is much debate... 

Using conventional histology, it is not always easy to distinguish apoptosis from necrosis they can occur simultaneously, depending on the intensity and duration of the stimulus, the extent of ATP depletion, and so on. Table 16.2 compares some of the major morphological features of apoptosis and necrosis. 

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