Testicular cancer overview

# Overview
Testicular cancer is cancer that develops in the testicles, a part of the male reproductive system. According to World Health Organization, testicular cancer may be classified into six subtypes based on the histopathology.Testicular cancer is a rare type cancer accounting about 0.5% of all new cancer cases in U.S. with germ cell tumor being the most common.Testicular cancer must be differentiated from epididymitis, hematocele, hydrocele, spermatocele, granulomatous orchitis, and varicocele. The prevalence of testicular cancer is approximately approximately 9,310 new cases of testicular cancers in the United States.The incidence of testicular cancer is approximately 5.88 per 100,000 males in the United States. Common risk factors in the development of testicular cancer are undescended testicle, family history, personal history of testicular cancer, Klinefelter syndrome.The most common symptoms of testicular cancer include a painless lump in the testicle, swelling of the testicle, and weight loss. An elevated concentration of blood tumor marker such as human chorionic gonadothrophin (HCG), alpha fetoprotein (AFP) tests is diagnostic of testicular cancer. The diagnostic test of choice is scrotal ultrasound along with biopsy. The predominant therapy for testicular cancer is surgical resection. Adjunctive chemotherapy and radiation therapy may be required. Prognosis of testicular cancer is generally good but it depends on the subtype. 5-year survival rate is approximately 96.6%.

# Historical Prospestive
There is a limited information about the historical perspective of testicular germ cell tumors. Leydig cells were first discovered by Franz Leydig who was a German anatomist in 1870.

# Classification
Testicular cancer is a very rare type of cancer. Based on the histopathological features, testicular cancer may be classified into six subtypes: germ cell tumors, sex-cord stromal tumors, tumors containing both germ cell and sex-cord stromal elements, miscellaneous tumors of the testis, hematolymphoid tumors, and tumors of collecting duct and rete testis.

# Pathophysiology
The pathophysiology of testicular cancer depends on the histological cell subtypes and findings. Most testicular cancers derived from the lack of differentiation of primordial germ cell into spermatogonia. Germ cells testicular tumor have some genetic component while most sex cord stromal testicular cancer are hormonal dependent. Most gross pathology of testicular tumors look similar on the physical appearance. On microscopic histopathological analysis of testicular cancer, fried-egg appearance is the characteristic finding of seminoma; marked nuclear atypia is the characteristic finding of embryonal carcinoma; hyaline-type globules, and Schiller-Duval bodies are characteristic findings of yolk sac tumor  ; syncytiotrophoblasts and cytotrophoblast cells are the characteristic findings of choriocarcinoma, Polymorphism with"spirene" chromatin for spermatocytic.

# Causes
There are no direct causes for testicular cancer. However, there are some common risk factors that may lead to gene mutations and cause the testicular cancer.

# Differential Diagnosis
Testicular cancer must be differentiated from epididymitis, hematocele, hydrocele, spermatocele, granulomatous orchitis, and varicocele.

# Epidemiology and Demographics
Testicular cancer is a rare type cancer accounting about 0.5% of all new cancer cases in U.S. In 2018, the estimate prevalence of testicular cancer is approximately 9,310 new cases of testicular cancers in the United States. The incidence of testicular cancer is approximately 5.7 per 100,000 men per year based on 2011-2015 report in the United States. The majority of cases are reported in New Zealand. Testicular cancer commonly affects more white males than any other races and black males are less affected by it. Testicular cancer is commonly affects men aged 20-44 years old and median age depends on the subtype.

# Risk Factors
Common risk factors in the development of testicular germ cells cancer are undescended testicle, family history, personal history of testicular cancer, and Klinefelter syndrome. There are no known risk factors for testicular sex cord stromal tumors.

# Screening
According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for testicular cancer.

# Natural History, complication and Prognosis
Prognosis of testicular cancer is generally good, and the 5-year survival rate is approximately 96.6% (2004-2010). Common complications of testicular cancer include metastasis, bleeding, infection, and infertility.

# Diagnostic Study of choice
The diagnostic study of choice for testicular cancer is scrotal ultrasound.

# History and Symptoms
The most common symptoms of testicular cancer include a painless lump in the testicle, swelling of the testicle, and weight loss.

# Physical Examination
Common physical examination findings of testicular cancer include weight loss, swelling of the testicle , and a painless mass in the testicle.

# Laboratory Findings
An elevated concentration of blood tumor marker tests is diagnostic of testicular cancer.

# X Ray
There are no X-ray findings associated with testicular cancer. Chest X-ray may be required in case of testicular tumor metastases into the lungs and mediastinum.

# CT Scan
CT scan may be helpful in the diagnosis of testicular cancer.

# MRI
MRI may be helpful in the diagnosis of testicular cancer for Extension of the metastasis and differentiating the seminomas from the nonseminomatous germ cells tumors.

# Ultrasound
Ultrasound may be helpful in the diagnosis of testicular cancer. Findings on ultrasound suggestive of testicular cancer mass include well defined well circumscribed hypoechoic lesion for seminoma; calcification, cystic spaces, and heterogeneous for nonseminomatous germ cell tumors.
Ultrasound may be helpful in the diagnosis of testicular cancer.

# Other Imaging Findings
There are no other imaging findings associated with testicular cancer.

# Other Diagnostic Findings
There are no other diagnostic findings associated with testicular cancer.

# Biopsy
Biopsy is rarely done in the diagnosis of testicular cancer. However, Inguinal biopsy may be done in the contralateral testis if the ultrasound showed the intratesticular mass, cryptorchid testis, marked atrophy, and suspicious mass. Other indications for testicular biopsy are obstructive azoospermia, testicular sperm extraction and diagnosis of carcinoma in situ of the testis.

# Medical Therapy
The predominant therapy for testicular cancer is surgical resection. Adjunctive chemotherapy and radiation therapy may be required.

# Surgery
Surgery is the mainstay of treatment for testicular cancer. Radical inguinal orchiectomy is recommended for every patient with testicular cancer for cure and histology.

# Primary Prevention
There are no established measures for the primary prevention of testicular cancer.

# Secondary Prevention
There are no secondary preventive measures available for testicular cancer.