Morphology

cells or tissues. Morphologic changes are concerned with both the gross anatomic and microscopic changes that are char­acteristic of a disease. Histology deals with the study of the cells and extracellular matrix of body tissues. The most common method used in the study of tissues is the prepa­ration of histologic sections that can be studied with the aid of a microscope. Because tissues and organs usually are too thick to be examined under a microscope, they must be sectioned to obtain thin, translucent sections. Histologic sections play an important role in the diagnosis of many types of cancer. A lesion represents a pathologic or traumatic discontinuity of a body organ or tissue. Descriptions of le­sion size and characteristics often can be obtained through the use of radiographs, ultrasonography, and other imaging methods. Lesions also may be sampled by biopsy and the tissue samples subjected to histologic study.