History
A 3-week-old sexually intact male Brahman twin calf presented for evaluation of an enlarged scrotum to the Food Animal Reproduction and Medicine Service, College of Veterinary Medicine, University of Florida.
The farm reported that at birth, assistance was required as the twins were delivered vaginally. The calves were tubed with colostrum replacer initially and remained in a pasture with the dam. No other issues were reported until the large scrotum was observed; however, the exact duration or progression of the enlargement was unknown. The twin brother appeared healthy, with no clinical abnormalities present at the time.
On physical examination, the calf had normal vital parameters. The calf’s navel was thickened with mild, purulent discharge. The joints were evaluated with no abnormalities; lameness was not observed. There were no obvious signs of systemic septicemia.
On palpation of the scrotum and contents, there was no obvious inguinal hernia and the skin was intact and had a normal thickness. What appeared to correspond to the left testicle/epididymis was enlarged, very firm, and homogenous on palpation (180-mm circumference, 120-mm length, and 75-mm width). There was no normal differentiation between testicular and epididymal tissues. A small right testicle was palpable caudodistal to the scrotal mass. Ultrasonographic examination of the scrotum was performed with a transabdominal linear low-frequency transducer (2 to 6.4 MHz). Ultrasonography revealed a severely enlarged, heterogeneously hypoechoic left testicle/epididymis with an ovoid shape and smooth margins (Figure 1). Throughout the parenchyma, there were multiple different-sized, ill- and well-defined, round, ovoid, and irregular heterogeneously hyperechoic nodules.
Longitudinal ultrasonographic images of the left testicle of the 3-week-old sexually intact male Brahman twin calf. The left testicle/epididymis is severely enlarged and heterogeneously hypoechoic with an ovoid shape and smooth margins. Throughout the testicular parenchyma, there are multiple different-sized, ill- and well-defined, round, ovoid, and irregular heterogeneously hyperechoic nodules (asterisks).
Citation: Journal of the American Veterinary Medical Association 260, 13; 10.2460/javma.22.08.0340
Longitudinal ultrasonographic images of the left testicle of the 3-week-old sexually intact male Brahman twin calf. The left testicle/epididymis is severely enlarged and heterogeneously hypoechoic with an ovoid shape and smooth margins. Throughout the testicular parenchyma, there are multiple different-sized, ill- and well-defined, round, ovoid, and irregular heterogeneously hyperechoic nodules (asterisks).
Citation: Journal of the American Veterinary Medical Association 260, 13; 10.2460/javma.22.08.0340
Longitudinal ultrasonographic images of the left testicle of the 3-week-old sexually intact male Brahman twin calf. The left testicle/epididymis is severely enlarged and heterogeneously hypoechoic with an ovoid shape and smooth margins. Throughout the testicular parenchyma, there are multiple different-sized, ill- and well-defined, round, ovoid, and irregular heterogeneously hyperechoic nodules (asterisks).
Citation: Journal of the American Veterinary Medical Association 260, 13; 10.2460/javma.22.08.0340
Longitudinal ultrasonographic images of the left testicle of the 3-week-old sexually intact male Brahman twin calf. The left testicle/epididymis is severely enlarged and heterogeneously hypoechoic with an ovoid shape and smooth margins. Throughout the testicular parenchyma, there are multiple different-sized, ill- and well-defined, round, ovoid, and irregular heterogeneously hyperechoic nodules (asterisks).
Citation: Journal of the American Veterinary Medical Association 260, 13; 10.2460/javma.22.08.0340
Longitudinal ultrasonographic images of the left testicle of the 3-week-old sexually intact male Brahman twin calf. The left testicle/epididymis is severely enlarged and heterogeneously hypoechoic with an ovoid shape and smooth margins. Throughout the testicular parenchyma, there are multiple different-sized, ill- and well-defined, round, ovoid, and irregular heterogeneously hyperechoic nodules (asterisks).
Citation: Journal of the American Veterinary Medical Association 260, 13; 10.2460/javma.22.08.0340
Question
What are the most likely causes for the testicular/epididymal enlargement observed in this calf?
Answer
Orchitis, epididymitis, Sertoli cell tumor, testicular yolk sac tumor, and teratoma are the most likely differential diagnoses.
Results
The decision was made to castrate the calf and treat the navel infection. The calf received a single dose of ceftiofur crystalline-free acid (Excede; 6.6 mg/kg, SC) at the base of the ear. Routine castration took place in the field 48 hours after the calf had been treated. Meloxicam (1 mg/kg) was given orally, and lidocaine (2.5 mL) was injected into the spermatic cords. The scrotum was clipped and cleaned aseptically. A horizontal incision was made into the skin of the distal scrotum, below the testicles. The parietal tunic was manually dissected from the right testicle, and an additional blunt dissection was required due to scarred, adhered tissues at the enlarged left testicle. A 14-inch modified serra emasculator was applied to each cord for hemostasis. Testicles were removed, and the scrotal incision was left open to drain and heal by second intention. A topical wound spray (AluSpray) was applied directly to the wound, and a fly repellant was sprayed at the base of the scrotum.
The enlarged left testicle measured 12.0 × 3.5 × 3.5 cm, while the right testicle appeared atrophic, measuring 5.0 × 1.5 × 1.0 cm. On gross examination, the markedly enlarged left testicle was firm and the outer tunics were mottled red to purple. On longitudinal sectioning of the testicle, the parenchyma was expanded by multifocal to coalescing, 0.5- to 2.0-cm foci of a light yellow to white caseous material. These foci were delineated by thick regions of gray-white fibrous tissue that further thickened the outer tunics. The soft tissues of the proximal spermatic cord were moderately expanded by a red gelatinous material (tissue edema). The contralateral testicle was red to beige and markedly reduced in size. On the longitudinal section, the contralateral testicular parenchyma was mottled red to beige with a soft, gelatinous to friable texture. Both testicles were serially sectioned and held in neutral-buffered 10% formalin for fixation. On histologic examination, much of the testicular parenchyma was effaced by pyogranulomatous inflammation and fibrosis (Figure 2). In these areas, multifocal to coalescing, high-density aggregates of degenerate neutrophils admixed with karyorrhectic debris, and an eosinophilic granular material was present. Delineating and separating these inflammatory foci were broad streams and bundles of mature fibrovascular tissue (consistent with granulation tissue). Intermittently in the granulation tissue were mildly dilated tubules lined by a ciliated tall columnar epithelium (consistent with remnant epididymal tubules). In the contralateral testicle, diffusely the seminiferous tubules had a moderate decrease in diameter, were lined by 1 to 2 cell layers of spermatogenic epithelial cells, and were largely devoid of spermatids.
A—On longitudinal sectioning, the testicular and epididymal parenchyma are expanded by variable diameter, coalescing foci of caseous necrosis (asterisks) intersected with fibrous tissue. B—Microscopically the testicular parenchyma was replaced by dense aggregates of degenerate neutrophils (asterisks) surrounded by high numbers of macrophages (pyogranuloma) and broad, bridging streams of granulation tissue. H&E stain; bar = 100 µm.
Citation: Journal of the American Veterinary Medical Association 260, 13; 10.2460/javma.22.08.0340
A—On longitudinal sectioning, the testicular and epididymal parenchyma are expanded by variable diameter, coalescing foci of caseous necrosis (asterisks) intersected with fibrous tissue. B—Microscopically the testicular parenchyma was replaced by dense aggregates of degenerate neutrophils (asterisks) surrounded by high numbers of macrophages (pyogranuloma) and broad, bridging streams of granulation tissue. H&E stain; bar = 100 µm.
Citation: Journal of the American Veterinary Medical Association 260, 13; 10.2460/javma.22.08.0340
A—On longitudinal sectioning, the testicular and epididymal parenchyma are expanded by variable diameter, coalescing foci of caseous necrosis (asterisks) intersected with fibrous tissue. B—Microscopically the testicular parenchyma was replaced by dense aggregates of degenerate neutrophils (asterisks) surrounded by high numbers of macrophages (pyogranuloma) and broad, bridging streams of granulation tissue. H&E stain; bar = 100 µm.
Citation: Journal of the American Veterinary Medical Association 260, 13; 10.2460/javma.22.08.0340
A—On longitudinal sectioning, the testicular and epididymal parenchyma are expanded by variable diameter, coalescing foci of caseous necrosis (asterisks) intersected with fibrous tissue. B—Microscopically the testicular parenchyma was replaced by dense aggregates of degenerate neutrophils (asterisks) surrounded by high numbers of macrophages (pyogranuloma) and broad, bridging streams of granulation tissue. H&E stain; bar = 100 µm.
Citation: Journal of the American Veterinary Medical Association 260, 13; 10.2460/javma.22.08.0340
A—On longitudinal sectioning, the testicular and epididymal parenchyma are expanded by variable diameter, coalescing foci of caseous necrosis (asterisks) intersected with fibrous tissue. B—Microscopically the testicular parenchyma was replaced by dense aggregates of degenerate neutrophils (asterisks) surrounded by high numbers of macrophages (pyogranuloma) and broad, bridging streams of granulation tissue. H&E stain; bar = 100 µm.
Citation: Journal of the American Veterinary Medical Association 260, 13; 10.2460/javma.22.08.0340
No intralesional bacteria, no intralesional acid-fast organisms, and no intralesional argyrophilic organisms (eg, fungi) were observed with Gram stain, Ziehl-Neelson stain, and Grocott methenamine silver stain, respectively.
Ancillary testing was submitted to the Florida Bronson Animal Disease Diagnostic Laboratory to aid in the determination of the causative agent. This included bacteriology/mycology aerobic and anaerobic cultures from a sterile swab and epididymal tissue, as well as serology screening for Brucella abortus. Heavy growth of Escherichia coli (β-hemolytic) and Enterobacter cloacae were reported. B abortus serum buffered acidified plate antigen was negative.
Discussion
Initial differential diagnosis for an enlarged scrotum should include inguinal hernia, of congenital or acquired origin, with abdominal contents present.1 Likewise, scrotal edema and hematocele could develop as a result of a testicular or scrotal injury while hydrocele is usually associated with peritoneal-related issues leading to fluid accumulation in the scrotum due to the communication of the vaginal tunics. These differentials were ruled out on evaluation of the calf by means of manual palpation, visual examination, and ultrasound of the scrotum and its contents.
At that point, with the enlargement specifically associated to the left testicle/epididymis, neoplasia remained a differential diagnosis irrespective of not being common in calves. Sertoli cell2 and testicular yolk sac tumors3 have been previously reported in young bulls and newborn calves, while Leyding cell tumors, teratomas, seminomas, and others are rare in cattle and more frequent in older bulls. Orchitis or epididymitis caused by bacterial infection was also considered.
With the gross and histologic evaluation of the left testicle and epididymis, neoplasia was ruled out. In an attempt to identify the causative agent, aerobic and anaerobic cultures and a serology test for B abortus were submitted. B abortus remains a differential diagnosis given that it is a reportable disease and, when present, typically invades the seminal vesicles, ampullae, testicles, and epididymis in infected bulls. B abortus infection was ruled out in this case by ancillary testing.
This report documents a case of chronic epididymitis in a 3-week-old calf. The marked chronicity of the infection given the calf’s age and lack of clinical illness is rare. There have been previous reports of epididymitis in newborn calves, in which Histophilus somni was isolated.4 H somni has previously been reported to cause epididymal enlargement; however, this bacterium was not isolated in this case. E coli and E cloacae were isolated in this case; to our knowledge, neither have been previously reported to be associated with bovine epididymitis. It was also possible that one or both isolated bacteria could have been present due to contamination since the samples were not sterile and castration took place in the field. Additionally, this calf was treated 2 days prior to castration with antibiotics; therefore, it was possible that we did not isolate the bacteria responsible for causing the epididymitis. This was supported by the absence of bacterial evidence in histologic samples.
The contralateral testicle was found to be atrophied, which is an expected observation when there is chronic inflammation and associated heat occurring in the other testicle. At the time of the initial examination, it was obvious that the damage to the testicles and associated structures was extensive and not compatible with the calf being a future breeding prospect. If caught early, there is a chance that the calf’s reproductive capabilities may have been salvaged through aggressive treatment and hemicastration of the affected testicle/epididymis.
The pathogenesis of chronic epididymitis in this calf was not known; nevertheless, we can consider ascending infection a likely route of transmission given the concurrent umbilical infection, perhaps through the urachus to the bladder to the prostatic urethra.5 However, systemic infection cannot be ruled out.
For the clinician, this case highlights the importance of adequate familiarity with the normal anatomy of the scrotum and its contents, as well as complete and thorough evaluation to determine diagnosis and prognosis. It is also a good example of the use of a problem-solving approach and a reminder that rare cases do occur.
Outcome
The calf recovered from castration and omphalitis uneventfully and returned to pasture with its dam and twin.
Acknowledgments
The authors declare that there were no conflicts of interest.
The authors thank the University of Florida Institute of Food and Agricultural Sciences Beef Research Unit for their willingness to facilitate evaluation of the calf.
References
- 1. ↑
Wolfe D. Section VIII: genital surgery – male. Current Veterinary Therapy: Food Animal Practice 5th ed. WB Saunders Co; 2008:356–363.
- 2. ↑
Vissiennon T, Freick M, Kilic E, et al. Sertoli cell tumour in a neonate calf: an unusual congenital tumour. A case report. Tierarztl Prax Ausg G Grosstiere Nutztiere 2016;44(6):371–378.
- 3. ↑
Sakaguchi K, Matsuda K, Suzuki H, et al. Testicular yolk sac tumor of myxomatous, reticular, and polyvesicular vitelline type in a newborn calf. J Vet Diagn Invest 2013;25(6):811–815.
- 4. ↑
Dobberstein R. Isolation of Histophilus somni and Trueperella pyogenes from a 2-month-old calf with chronic fibrosing and suppurative epididymitis. Can Vet J 2020;61(7):776–778.
- 5. ↑
Bauer SB, Retik AB. Urachal anomalies and related umbilical disorders. Urol Clin North Am 1978;5(1):195–211.
