Testicular Microlithiasis

A 17-year-old boy presented for a well-adolescent visit and had no complaints. However, his physical examination was remarkable for a body mass index of 33 kg/m² (98th percentile) and a scrotum that appeared enlarged (Figure 1). Palpation of the testes was difficult, but there were no signs of hernia or torsion. The rest of the physical examination was unremarkable, and his past medical and family histories were noncontributory. Scrotal ultrasonography with color and spectral Doppler imaging was performed, and the results showed bilateral testicular microlithiases and bilateral epididymal cysts (Figures 2-7). Furthermore, the scrotal ultrasonography showed normal testicular size without the presence of a hydrocele or a spermatocele. 

DISCUSSION

Testicular microlithiasis. Testicular microlithiasis is an uncommon incidental finding identified during sonographic examination for evaluation of scrotal abnormalities.¹ It can be found in pediatric patients of all ages, but it is rare in patients under 2 years of age.² These densities are thought to originate from the degeneration of epithelial cells in the seminiferous tubules or from Sertoli cell dysfunction due to abnormal gonadal development.^3,4 

Our patient had classic microlithiasis, which is defined as > 5 microprecipitates measuring 1 to 3 mm in diameter in at least one sonographic plane of a testicle.⁵ Fewer than 5 microliths on a single image is considered limited testicular microlithiasis.⁶ The prevalence of testicular microlithiasis ranges between 0.6% and 9% in patients referred for scrotal ultrasonography.^7,8 

Testicular microlithiasis is more common in patients with other testicular pathologies, including cryptorchidism, varicocele, pseudohermaphroditism, germ cell tumors, and infertility. The condition is also more common in patients with Down or Klinefelter syndromes.^1,9-12 Testicular microlithiases occur in up to 50% of patients with cryptorchidism and up to 40% in patients with germ cell tumors.¹³ They have also been associated with similar calcifications in other anatomic locations, including the lungs and the central nervous system.¹⁴  

Testicular microlithiasis may also be linked to an increased risk of testicular malignancy as well as an increased frequency of infertility.^15-17 Microliths are more common in testes with cancer than in those without malignant pathology, and, although it is debatable if testicular microlithiasis is an independent risk factor for testicular cancer, it is generally accepted that there is an increased risk of testicular cancer in patients with proven testicular microlithiasis.^7,17-19 The most commonly reported testicular cancer subtypes reported in patients with confirmed testicular microlithiasis include seminomas, teratomas, and mixed germ cell tumors.²⁰ Although the exact incidence of testicular malignancies seen in patients with testicular microlithiasis is unknown, one literature review and meta-analysis showed there was a significantly increased risk of testicular germ cell tumors or germ cell neoplasia in situ in men with proven testicular microlithiasis compared with those in whom testicular microlithiasis was not found.²¹

Epididymal cysts. Epididymal cysts are benign, painless cysts of the epididymal head and, similarly to testicular microlithiasis, are usually diagnosed during sonographic evaluation for other testicular pathologies.²² Epididymal cysts occur in 5% to 20% in the pediatric population.^23-25 Although the etiology of these cysts is unknown, they may result from congenital anomalies related to hormonal dysfunction during embryogenesis or from epididymal duct obstruction.^25-29 On examination, epididymal cysts can be solitary or multiple and present as fluctuant, firm testicular swellings that are easily distinguishable from the testicle.²⁴ Conservative treatment with clinical and ultrasonography monitoring is recommended for asymptomatic patients. Surgical treatment is reserved for patients with large or symptomatic epididymal cysts.^25,28-30

CONCLUSION

A genitourinary examination should be part of every well child or adolescent visit, even in patients without complaints. The etiology of our patient’s enlarged scrotum was unclear but was unlikely related to the epididymal cysts or testicular microlithiasis. It is also unclear whether serial physical examinations and ultrasonography are beneficial.³¹ In the case of microliths, follow-up recommendations can be based on past medical history if the patient has a high risk for testicular cancer due to other factors, such as undescended tests, infertility, testicular atrophy, and contralateral testicular cancer. In addition, regular testicular self-examination is recommended for all patients diagnosed with testicular microlithiasis or epididymal cysts.n

Hunter Nolen, BS; Vikas Gupta, BS; and Micah Gibson, BS, are from the John P. and Kathrine G. McGovern Medical School at University of Texas Health Science Center in Houston.

Lynnette Mazur, MD, MPH, is a Professor of Pediatrics at the John P. and Kathrine G. McGovern Medical School at University of Texas Health Science Center in Houston.

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