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Testicular Microlithiasis: Is Testicular Microlithiasis an early indicator of testicular cancer? By Melissa Robertson
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Abstract
Since it’s development in 1974, ultrasound has become the modality of choice for evaluating the scrotum. Today ultrasound is nearly 100% accurate in the detection of scrotal pathology. Sonographically the testicles should appear homogenous and midlevel gray. Cyst, tumors, hydroceles, infections, and microliths are sometimes seen during these exams. The presence of innumerable tiny echogenic foci or “speckles” also known as microlithiasis is uncommon. Testicular microlithiasis has a characteristic appearance and has not been associated with any other testicular abnormality; therefore it is unnecessary to perform biopsies or excisions. The exact cause of testicular microlithiasis is unclear and its presence may serve as a marker of an abnormal testis. Bilateral testicular carcinoma is associated with microlithiasis but there is not sufficient evidence that microlithiasis adds independent diagnostic information.
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Keywords
Testicular microlithiasis, Scrotum ultrasound, testicular carcinoma, hyperechoic foci
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Objective
Often an incidental finding on routine scrotum ultrasounds, testicular microlithiasis is an unprogressive, asymptomatic condition consistent with bilateral or unilateral hyperechoic foci measuring 1-2mm in the testicle. Patients with testicular cancer have increased incidence of testicular microlithiasis. Is this a coincidence or is there a direct correlation between testicular cancer and testicular microlithiasis? The purpose of this paper is to define testicular microlithiasis and to relate the prevalence of testicular microlithiasis to the incidence of testicular cancer.
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Anatomy and Function of the Scrotum
The scrotum, located outside of the body, is a highly vascular cutaneous pouch divided into two compartments by a septum. The testes, epididymis, and spermatic cord are contents of the scrotum. (1) The adult testicle is an ovoid gland encapsulated by a dense fibrous tissue called the tunica albuginea. (2) The main function of the testes is to produce sperm and testosterone. Sperm is created by germ cells inside the seminiferous tubules and stored inside the epididymis until it matures. (3) The epididymis is a curved structure measuring 6-7cm in length that lies posterolateral to the testicle. (2) The spermatic cord, which lies lateral to the testes, contains testicular and differential arteries and the pampiniform plexus veins, which control blood flow in the testes. (3)
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Ultrasonography
Many times patients present to the emergency room or to their primary care physician with sudden onset of scrotum pain. Testicular conditions are hard to diagnose by physical examination or laboratory test alone. Since it’s development in 1974,ultrasound has become the modality of choice for evaluating the scrotum. Before the 1970’s surgical exploration was the only way to diagnose a testicular mass. Today ultrasound is nearly 100% accurate in detection of scrotal pathology. Ultrasound examinations are quick, easy for patients to tolerate, and are cost efficient. Ultrasound has the ability to image intratesticular and extratesticular abnormalities and has a high accuracy in differentiating cystic lesions from solid lesions. Sonographically the testicles should appear homogenous and mid-level gray. The head of the epdidymis is slightly hyperechoic or isoechoic and appears coarser than the testicle. The body and tail of the epididymis and the spermatic cord are not seen on ultrasound. (4) A 10mHz broadband linear transducer capable of high-resolution imaging is used, but a lower frequency transducer can be used on swollen testicles. (5) Many abnormalities can be diagnosed with the use of ultrasound. Cyst, tumors, hydroceles, infections, and microliths are sometimes seen. These findings can be incidental or they can be the cause of the pain. Focal echogenicities are often seen in the testicular parenchyma; these are typically few in number and are due to spermatic granulomas, isolated intraluminal calcifications, or phleboliths. Large Diffusely hyperechoic testicular masses may represent benign processes such as fibrosis or granulomas. The presence of innumerable tiny echogenic foci or “speckles” also known as microlithiasis is uncommon. The sonographic appearance of testicular microlithiasis is characteristic and has not been described in association with any other testicular abnormality and is therefore biopsy and excisions are unnecessary. (6)
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Testicular MIcrolithiasis and Cancer
Priebe and Garret reported the first case of testicular microlithiasis in 1970 in a healthy 4-year-old boy. Doherty described the sonographic appearance in 1987 as small, non-shadowing 1-3mm hyperechoic foci. Occurring bilaterally or in a single testicle, testicular microlithiasis has been associated with Klinefelter’s syndrome, cryptorchidism, Down’s syndrome, male pseudohemaphroditism, pulmonary alveolar microlithiasis, and previous radiotherapy. The exact cause of testicular microlithiasis is unclear, but is thought to be a result of a defective phagocytosis of degenerative tubular cells by sertoli’s cells. Testicular microlithiasis may act as a marker of an abnormal testis and can be associated with testicular malignancy. (7) Testicular cancer has an annual incidence of three cases per 100,000 men and comprises approximately 1% of all malignancies in men. (8) Peaking between the ages of 15-45, it accounts for 9% of deaths from malignant disease. Men with a history of testicular cancer are 500-700 times more likely to develop cancer in the contralateral testis than the general male population. Testicular microlithiasis, identified on 0.6-5.6% of testicular ultrasounds, has been associated with an increased incidence of testicular cancer. (8) About 95% of primary testicular tumors are of germ cell origin. Seminoma is the most common single cell type of germ cell tumor accounting for 40% of all germ cell tumors. They are the most radiosensitive and have a cure rate of 80-95%. Numerous cases of microlithiasis in association with germ cell tumors have been reported but the exact premalignant potential is unknown. A multi-center study demonstrated a 40% incidence of coexistent germ cell tumor and testicular microlithiasis. (9) After orchiectomy five of ten patients with microlithiasis had a second testicular malignancy. Although bilateral testicular carcinoma is associated with microlithiasis, there is not sufficient evidence that microlithiasis adds independent diagnostic information to the presence of a mass or heterogenous change. Therefore, surgery should not be performed for microlithiasis alone in an otherwise normal appearing testis. (8) Men who demonstrate testicular microlithiasis should have follow-up ultrasound exams until the age of 50. The ultrasound appearance of germ cell tumors is nonspecific and is usually hypoechoic to the normal testis (10) In rare cases malignancy arises in testes under surveillance. (9) A study was performed over a 32-month period, 4,819 patients from four referral centers had scrotum ultrasounds. Of these men, 54 tumors were found. 28 seminomas, 14 teratomas, 8 mixed germ cells, 2 Leydig cell tumors, and 2 non- Hodgkin’s lymphomas. Testicular Microlithiasis was found in 33 patients. The prevalence was 0.68%. Concurrent tumor and testicular Microlithiasis was 21.6%. In this study almost 22% of the 54 patients had both testicular cancer and testicular microlithiasis. (7)
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Total number of Scrotum US in 32 Months 4,819
Total number of Tumors Found 54
Types of Tumors: Seminoma 28
Teratomas 14
Mixed Germ Cell 8
Leydig Cell 2
NonHodgkin’s Lymphoma 2
Total patients with TesticularMicrolithiasis 33
Prevalence .68%
Concurrent Tumor &Testicular Microlitiasis 21.6%
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Conclusion
Testicular Microlithiasis is a condition characterized by tiny calcifications in the testes. There is a questionable relationship between testicular microlithiasis and testicular cancer. Although this relationship is hard to prove, it may suggest that testicular microlithiasis indicates an underlying abnormality and may be a good indication of possible malignant potential. There was not sufficient evidence that intratesticular microlithiasis adds independent diagnostic information for testicular cancer in the absence of a mass of heterogenous changes. (8) Nonetheless, yearly screenings of patients under the age of 50 with testicular microlithiasis has been suggested to monitor for possible malignancy. (7)
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References
1. Krebs C, Giyanani V, Eisenberg R: Ultrasound Atlas of Disease Processes. Appleton & Lange 1993; p387-403
2. Rumack C, Wilson S, Charboneau J: Diagnostic Ultrasound. volume 1: Mosby 1991; (26) p565-587
3. Sarti D, Diagnostic Ultrasound: Text and Cases.(2) Year Book Medical Publishers, Inc.1987; p571-607
4. Hagen-Ansert S, Textbook of Diagnostic Ultrasonography. (5) volume 1:Mosby 2001; (15) p 408-428
5. Blaivas M, Brannam L, Emergency Medicine Clinics of North America. Testicular Ultrasound. Saunders Company 2004: Available at http://home.mdconsult.com/. Accessed on October 23,2005.
6. Janzen D, Mathieson J, Marsh J, Cooperberg P, Rio P, Golding R, Rifkin M, American Journal of Roentgenology: Testicular Microlithiasis: Sonographic and Clinical Features. Available at http://www.ajronline.org/. Accessed on November 2,2005.
7. American Journal of Roentgenology. Testicular Microlithiasis: Prevalence of Tumor Risk in a Population Referred for Scrotal Sonography. Available at http://www.ajronline.org/ . Accessed on November 2,2005.
8. Bach A, Hann L, Shi W, Giess C, Yoo H, Sheinfeld J, Thaler H, American Journal Roentgenology: Is There an Increased Incidence of Contralateral Testicular Cancer inpatients with Intratesticular Microlithiasis? Available at http://www.ajronline.org/. Accessed on November 2,2005.
9. Grainger & Allison’s Diagnostic Radiology: A textbook of Medical Imaging. (4) Testicular Masses; Churchill Livingstone, Inc. 2001; Available at http://home.mdconsult.com/. Accessed on October 15,2005.
10. Machin J, Scrotal Ultrasound: Recent Advances Including Color Doppler. Mid-south Imaging & Therapeutics, P.A. Available at http://msit.com/phys_art1.html. Accessed on October 23,2005.
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