PMC10090384_01
Stallion reproductive parameters collected during 2008-2019: (A) total semen sample volume collected; (B) progressive sperm motility; (C) sperm concentration; (D) total and motile number of spermatozoa per ejaculate. An abrupt decrease in the volume of the semen sample associated with a peak in total sperm concentration was noted in 2014, although the numbers of total and motile spermatozoa present were reduced. In 2018 and 2019, the highest values of semen volume were registered, accompanied by high values of progressive motility. Nevertheless, sperm concentration decreased from 2015 to 2019, presenting a decrease in the number of total and motile spermatozoa that reached minimal values in 2019. - - Lesion's clinical diagnosis.
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F1
Semen evaluation was also frequently performed in classes and results of the reproductive parameters collected from 2008 to 2019 are depicted in Figure 1.
Purebred Lusitano stallion, right testis. (A) Ultrasound showed a well-circumscribed anechoic cystic structure (yellow arrow) in the epididymis. Red arrow: Epididymal wall. (B) Macroscopically, the largest cystic lesion (*) is filled with whitish and semen-like material located in the terminal portion of the body of the epididymis. Several smaller cavities were also identified in the tail of the epididymis.
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F2
However, in 2011, a cyst-like structure was easily detected in the tail of the right epididymis, apparently measuring 1.8 cm in its largest dimension (Figure 2A). Additionally, several well-defined cavities with similar content were observed, replacing the entire tail of the organ and measuring between 0.2 and 0.7 cm in diameter (Figure 2B).
Schematic representation and histopathological photomicrographic of the stallion's testes. Left testis: parenchyma (A), epididymal body (B) and epididymal tail (C). Right testis: parenchyma (D), epididymal cyst (E) and epididymal tail (F). (A, D) Seminiferous ducts surrounded by germinal epithelium containing a large amount of exfoliated germ cells and round bodies in the lumen (H&E, 100x); Inset: Presence of spermatocytes, spermatids, and some spermatozoa in the lumen of the ducts (H&E, 400x). (B) Normal epididymal body (H&E, 40x). (E) Dilated cavity containing spermatozoa in the lumen, associated with foci of granulomatous reaction- spermatic granuloma (arrow) (H&E, 40x); Inset: The lesion is circumscribed by fibrosis and a dense muscular layer, evidenced by Masson's Trichrome histochemical staining (40x). (F) Enlarged ducts in the tail of the epididymis, compared to those of the normal contralateral testis; Note the sperm stasis in some ducts which are filled with sperm (arrowhead) (H&E, 40x).
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F3
The lesion consisted of several cavities of variable size with walls lined by a multifocally hyperplastic and low columnar ciliated epithelium, externally circumscribed by well-organized smooth muscle bundles that stained accordingly with Masson Trichrome (Figure 3).
Foreign body inflammatory reaction in response to sperm extravasation, consisting of numerous multinucleated giant cells (arrows) (H&E, 600x).
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F4
In the adjacent tissue, several foci of foreign body inflammatory reaction centered in free sperm were observed, composed of numerous macrophages exhibiting intense phagocytic activity, multinucleated giant cells and plasma cells (Figure 4).