Testis, Germinal Epithelium - Atrophy
comment:Germinal epithelium atrophy ( Figure 1 , Figure 2 , Figure 3 , and Figure 4 ) consists of seminiferous tubules that are completely devoid of germ cells and lined only by Sertoli cells. The seminiferous tubules may have dilated lumens ( Figure 1 and Figure 2 ) or contracted lumens ( Figure 4 ).
If the tubular lumens are dilated, the atrophy is likely caused by pressure (i.e. pressure atrophy) fromprolonged and severe tubular dilation (also see Testis, Seminiferous Tubule - Dilation) The change may be unilateral or bilateral and focal, multifocal, or diffuse and occurs as an occasional incidental finding in mice and rats at all ages, with the incidence increasing with age. Germinal epithelial atrophy is an end-stage lesion and is generally preceded, or accompanied by, seminiferous tubule degeneration. Depending on severity, the affected testes may be macroscopically flaccid and reduced in size and weight. Severe, diffuse germinal epithelial atrophy is often irreversible. Scattered seminiferous tubules with germinal cell atrophy can be seen as an aging change in rats.
recommendation:Germinal epithelial atrophy should be diagnosed, graded and should be discussed in the pathology narrative if it is considered the primary change and if the incidence and/or severity appears to be related to chemical administration. Since germinal epithelial atrophy is considered the end stage of degeneration, the diagnosis of atrophy should be reserved for cases in which the majority of the affected tubules are devoid of germ cells, otherwise, degeneration is a more appropriate diagnosis (see Testis, Germinal Epithelium - Degeneration). If there is a mixture of effects (both atrophied and degenerative tubules), it can be described in the pathology narrative. If both terms are used in a single study, it is incumbent upon the pathologist to describe the relationship between the two lesions in the pathology narrative. If both testes are affected, the diagnosis should be indicated as bilateral and the severity grade based on the more severely affected testis.
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