Testicular microlithiasis is a relatively uncommon condition that represents the deposition of multiple tiny calcifications throughout both testes.
The most common criterion for diagnosis is that of five microcalcifications in one testicle, although definitions have varied in the past. In the majority of cases, testicular microlithiasis is bilateral.
Testicular microlithiasis is seen in up to 0.6% of patients undergoing scrotal ultrasound. Some reports suggest that it may present in up to 5.6% of the general population between 17 and 35 years of age 3. Although testicular microlithiasis is present in ~50% of men with a germ cell tumor, it is very common in patients without cancer, and a direct relationship between the two has been debated.
- testicular germ cell tumor
- Klinefelter syndrome
- testicular infarct
- testicular granulomatous disease
- infertility 17
- Down syndrome
- alveolar microlithiasis
Testicular microlithiasis per se is asymptomatic and is usually found incidentally when the scrotal content is examined with ultrasound, or found in association with symptomatic conditions.
The microcalcifications are likely a marker of tubular degeneration, but not a risk factor for tubular degeneration 10.
Ultrasound is the modality of choice for examining the testes. Microlithiasis appears as small non-shadowing hyperechoic foci ranging in diameter from 1-3 mm. These foci, often uniformly sized, occur within the testicular parenchyma and although usually distributed uniformly, may be distributed peripherally or segmentally 2.
One classification scheme used on ultrasound, suggested by ESUR scrotal imaging guidelines is 13:
- limited TML: less than 5 microcalcifications per field of view
- classic TML: greater than or equal to 5 microcalcifications per field of view
- diffuse TML: numerous microcalcifications
It is unclear if a grading system adds prognostic value, however, relative to follow up based on known risk factors.
Treatment and prognosis
Testicular microlithiasis is in itself asymptomatic and benign. A relationship with testicular tumors, in particular germ cell tumors (GCT) is controversial. An ~12 fold increased risk of GCT in symptomatic testicles with microlithiasis has been reported (with microlithiasis found in approximately 50% of GCT cases), however, no increased risk has been found in asymptomatic testicles. It is also unclear whether early detection confers any benefit over self-exam. As such, screening is unlikely to be beneficial 1,17.
Some publications advise routine self-examination rather than sonographic surveillance 5 while others recommend annual ultrasound follow up when it is accompanied by other premalignant factors 6.
The European Society of Urogenital Radiology (ESUR) advises annual ultrasound follow-up until age 55, only if a risk factor for malignancy is present 12 which include:
- testicular atrophy (e.g. volume under 12 cc)
- previous germ cell tumor 15
- family history of germ cell tumor
- 1. Tan IB, Ang KK, Ching BC et-al. Testicular microlithiasis predicts concurrent testicular germ cell tumors and intratubular germ cell neoplasia of unclassified type in adults: a meta-analysis and systematic review. 2010;doi:10.1002/cncr.25231 - Pubmed citation
- 2. Cast JE, Nelson WM, Early AS et-al. Testicular microlithiasis: prevalence and tumor risk in a population referred for scrotal sonography. AJR Am J Roentgenol. 2000;175 (6): 1703-6. AJR Am J Roentgenol (full text) - Pubmed citation
- 3. Costabile RA. How worrisome is testicular microlithiasis?. Curr Opin Urol. 2007;17 (6): 419-23. doi:10.1097/MOU.0b013e3282f0ffea - Pubmed citation
- 4. Shanmugasundaram R, Singh JC, Kekre NS. Testicular microlithiasis: Is there an agreed protocol?. Indian J Urol. 2007;23 (3): 234-9. doi:10.4103/0970-1591.33442 - Free text at pubmed - Pubmed citation
- 5. DeCastro BJ, Peterson AC, Costabile RA. A 5-year followup study of asymptomatic men with testicular microlithiasis. J. Urol. 2008;179 (4): 1420-3. doi:10.1016/j.juro.2007.11.080 - Pubmed citation
- 6. Dagash H, Mackinnon EA. Testicular microlithiasis: what does it mean clinically?. BJU Int. 2007;99 (1): 157-60. doi:10.1111/j.1464-410X.2006.06546.x - Pubmed citation
- 7. Otite U, Webb JA, Oliver RT et-al. Testicular microlithiasis: is it a benign condition with malignant potential?. Eur. Urol. 2002;40 (5): 538-42. Pubmed citation
- 8. Dell'Acqua A, Tomà P, Oddone M et-al. Testicular microlithiasis: US findings in six pediatric cases and literature review. Eur Radiol. 1999;9 (5): 940-4. Pubmed citation
- 9. Miller FN, Sidhu PS. Does testicular microlithiasis matter? A review. Clin Radiol. 2002;57 (10): 883-90. Pubmed citation
- 10. Winter TC, Kim B, Lowrance WT, Middleton WD. Testicular Microlithiasis: What Should You Recommend?. AJR. American journal of roentgenology. 206 (6): 1164-9. doi:10.2214/AJR.15.15226 - Pubmed
- 11. de Gouveia Brazao CA, Pierik FH, Oosterhuis JW et-al. Bilateral testicular microlithiasis predicts the presence of the precursor of testicular germ cell tumors in subfertile men. J. Urol. 2004;171 (1): 158-60. doi:10.1097/01.ju.0000093440.47816.88 - Pubmed citation
- 12. Richenberg J, Belfield J, Ramchandani P et-al. Testicular microlithiasis imaging and follow-up: guidelines of the ESUR scrotal imaging subcommittee. Eur Radiol. 2015;25 (2): 323-30. doi:10.1007/s00330-014-3437-x - Pubmed citation
- 13. Richenberg J, Belfield J, Ramchandani P, Rocher L, Freeman S, Tsili AC, Cuthbert F, Studniarek M, Bertolotto M, Turgut AT, Dogra V, Derchi LE. Testicular microlithiasis imaging and follow-up: guidelines of the ESUR scrotal imaging subcommittee. (2015) European radiology. 25 (2): 323-30. doi:10.1007/s00330-014-3437-x - Pubmed
- 14. Thomas C. Winter, Bohyun Kim, William T. Lowrance, William D. Middleton. Testicular Microlithiasis: What Should You Recommend?. (2016) American Journal of Roentgenology. 206 (6): 1164-9. doi:10.2214/AJR.15.15226 - Pubmed
- 15. Balawender K, Orkisz S, Wisz P. Testicular microlithiasis: what urologists should know. A review of the current literature. (2018) Central European journal of urology. 71 (3): 310-314. doi:10.5173/ceju.2018.1728 - Pubmed
- 16. Trout AT, Chow J, McNamara ER, Darge K, Ramirez Grueso R, Munden M, Rothan SM, Navarro OM, Tijerín Bueno M, Bove KE, Chikwava KR, Heider A, Hicks MJ, Somers GR, Zhang B, Dillman JR. Association between Testicular Microlithiasis and Testicular Neoplasia: Large Multicenter Study in a Pediatric Population. (2017) Radiology. 285 (2): 576-583. doi:10.1148/radiol.2017162625 - Pubmed
- 17. Balawender K, Orkisz S, Wisz P. Testicular microlithiasis: what urologists should know. A review of the current literature. (2018) Central European journal of urology. 71 (3): 310-314. doi:10.5173/ceju.2018.1728 - Pubmed
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