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Testis - Sperm Stasis

Image of sperm stasis in the testis from a male B6C3F1 mouse in a chronic study
Testis - Sperm stasis in a male B6C3F1 mouse from a chronic study. Sperm stasis in a testicular tubule.
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Image of sperm stasis in the testis from a male F344/N rat in a chronic study
Testis - Sperm stasis in a male F344/N rat from a chronic study. Arrows indicate focal mineralization of sperm.
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Sperm stasis results from impaction of spermatozoa in a seminiferous tubule or rete testis duct. It is generally seen within an atrophic tubule, and the impacted sperm often become mineralized ( Figure 2image opens in a pop-up window , arrows). Sperm stasis is distinguished from a spermatocele by the smaller size of the tubule (in sperm stasis the tubule is less than twice the diameter of a normal tubule or duct) and from a sperm granuloma by the absence of an inflammatory response. Affected tubules are often located close to the rete. Sperm stasis is a common age-associated incidental finding that accompanies tubular degeneration and atrophy.


Sperm stasis should not be recorded or documented unless it is a prominent finding that occurs independent of germ cell degeneration or germinal epithelial atrophy. When a diagnosis is warranted, it should be given a severity grade, and bilaterality should be included in the diagnosis when present.


Creasy D, Bube A, de Rijk E, Kandori H, Kuwahara M, Masson R, Nolte T, Reams R, Regan K, Rehm S, Rogerson P, Whitney K. (2012). Proliferative and nonproliferative lesions of the rat and mouse male reproductive system. Toxicol Pathol 40:40S-121S.

NTP is located at the National Institute of Environmental Health Sciences, part of the National Institutes of Health.