MGT

• Normal adult testis


  • Paired organ that lies within the scrotum
  • Suspended by the spermatic cord
  • Average weight of each testis is 15 to 19 g, the right usually being 10% heavier than the left

  
• Testis capsule


  • Composed of three layers: the outer serosa or tunica vaginalis (covered by a flattened layer of mesothelial cells), the tunica albuginea, and the inner tunica vasculosa
  • The posterior portion of the capsule, called the mediastinum, contains blood and lymph vessels, nerves, and the mediastinal portion of the rete testis
• Testis parenchyma


  • Divided into approximately 250 lobules, each lobule containing up to four seminiferous tubules
• Tunica vaginalis


  Continuation of the peritoneum that lines the abdominopelvic cavity
• Tunica albuginea


  Fibrous capsule that covers each testis
• Tunica albuginea


  1. Gives rise to septa (partitions) that divide the testis into lobules (about 250)

  2. Each lobule contains 3 or 4 highly coiled seminiferous tubules

  3. These converge to become rete testis which transport sperm to the epididymis
• Cryptorchidism

  Absence of one or both testes in the scrotum
• Cryptorchidism


  • Most common congenital abnormality of the genitourinary tract
  • Associated with infertility and subfertility, testicular germ cell tumor, testicular torsion and inguinal hernia
  • In one out of every ten males, the testis has not descended into the scrotum at the time of birth but has remained in the inguinal region or abdomen
  • Most of these "retained" or "retractile" testes descend into the scrotum during the first year of life
  • In only 1 in 100 individuals will a permanent retention of the testis out side the scrotum occur a condition known as cryptorchidism
• Pathogenesis of cryptorchidism


  The exact pathogenesis is unknown, but most evidence favors a role for testosterone under the influence of the hypothalamic-pituitary axis
• Cryptorchidism


  • Unilateral in 80% of the cases
  • Long-term consequences may include testicular malignancy and infertility/subfertility
  • Undescended testicle may be located in the abdomen or inguinoscrotal region
  • 80% of undescended testicles palpated within inguinal canal or high scrotal area
  • 20% of undescended testicles not palpated
  • 50% lie in abdomen, 50% are atrophic
  • Associated with increased risk of testicular germ cell tumor
  • Increasing risk of malignancy with delayed treatment
  • Relative risk of malignancy is 2 - 8x; higher risks associated with delayed repair, bilateral cryptorchidism
  • Seminoma is most common malignancy
• Cryptorchid testes in adults


  Small and brown
• Histologic changes in cryptorchidism

  • Peritubular fibrosis
  • Seminiferous tubule atrophy
  • Decreased / absent spermatogenesis
  • Sertoli cell only seminiferous tubules: tubules with only bland, monotonous pale cells with granular cytoplasm attached to the basement membrane; absent germ cells and no spermatogenesis
• Testicular atrophy


  Nonneoplastic process characterized by the disappearance of tubular or germinal epithelium and replacement with variable degrees of fibrosis
• Causes of testicular atrophy


  • Vascular accident
  • Testicular torsion
  • Thrombosis
  • Trauma
  • Cryptorchidism
  • Genetic abnormalities, such as microdeletion of Y chromosome, persistence of Müllerian duct structures
  • Filariasis and other infectious etiologies
  • AIDS
  • Chemotherapy and radiation
  • Vasectomy, outflow obstruction
  • Hormonal imbalances (e.g., persistent FSH stimulation, elevated serum estrogen)
  • Sequela of COVID-19 infection
• Microscopic changes in testicular atrophy


  • Small tubules, thick basement membrane and few or no germ cells in Sclerotic tubules
  • Interstitial fibrosis
  • Increased Leydig cells
• Causes of male infertility


  • Pretesticular (extragonadal endocrine disorders usually originating in the pituitary or adrenal gland)
  • Testicular (primary diseases of the testes, little treatment available)
  • Post-testicular (mainly obstructions of the ducts leading away from the testes)
• Evaluation of infertile male

  • Clinical history and examination
  • Semen analysis
  • White blood cell count in semen
  • Detection of antisperm antibodies
  • Sperm function tests (cervical mucus interaction, ova penetration, hemizonal assay)
  • Testicular biopsy (particularly useful in azoospermia with normal endocrine findings)
• Testicular biopsy findings in azoospermia

  • Germ cell aplasia (Sertoli cell-only syndrome) (29%): tubules populated by only Sertoli cells, thickening of the tubular basement membrane; germ cells completely absent
  • Spermatocytic arrest (26%): halt of the maturation sequence, usually at the stage of the primary spermatocyte; no spermatids or spermatozoa despite presence of abundant cells in division
  • Generalized fibrosis (18%)
  • Normal spermatogenesis (27%)
• Sertoli cell only syndrome


  Complete absence of germ cells, with only Sertoli cells present in the seminiferous tubules
• Maturation arrest

  • Germ cell maturity ceases at a specific point, frequently at primary spermatocyte level; sperm counts usually zero (complete maturation arrest)
  • Similar to complete but a few late spermatids are present in a few seminiferous tubules (incomplete maturation arrest)
• Causes of maturation arrest


  • Diabetes mellitus
  • Toxins
  • Excess heat
  • Varicocele
  • Hypothyroidism
  • Irradiation
  • Postpubertal gonadotropin deficiency
  • Alkylating agents
• Histology of maturation arrest

  • Numerous spermatogonia
  • Few spermatocytes
  • No mature spermatozoa
  • Sertoli cells prominent since reduced germ cells
  • Tubules often contain degenerated cells
• Testicular torsion


  Rotation of the organ 360 degrees around its longitudinal axis resulting in interruption of its blood supply
• Causes of testicular torsion

  • Sudden severe physical exercise
  • Congenital anomalies that lead to increasing the mobility of the testis and epididymis (high attachment of tunica vaginalis on the spermatic cord, incomplete descend of the testis or absent of the scrotal ligaments)
• Testicular torsion


  • Sudden onset of severe scrotal pain followed by swelling and hemorrhagic infarction of the testicular germ cells within few hours
  • Recurrent incomplete torsion of the spermatic cord results in small fibrotic testis
• Inflammatory lesions of the testis


  • More common in the epididymis than in the testis proper
  • Associated with venereal disease, nonspecific epididymitis and orchitis, mumps, and tuberculosis
  • Nonspecific epididymitis and orchitis usually begin as a primary urinary tract infection with secondary ascending infection
  • Orchitis complicates mumps infection in roughly 20% of infected adult males but rarely occurs in children
  • Severe cases may be associated with considerable loss of seminiferous epithelium with resultant tubular atrophy, fibrosis, and sterility
• Hydrocele


  Collection of serous fluid in the scrotal sac (tunica vaginalis)
• Hydrocele


  • Either congenital or acquired due to inflammatory disorders of the epididymis and the testis
  • Uncomplicated hydrocele usually presented with unilateral scrotal swelling
• Hematocele


  Hemorrhage into a hydrocele
• Spermatocele


  Cystic enlargement of the efferent ducts or ducts of rete testis

  
• Varicocele


  Dilation of the testicular vein
• Varicocele


  • Usually asymptomatic
  • Most varicoceles are detected during the physical examination of infertile men
  • Usually accompanied by testicular atrophy resulting in infertility
  • Surgical treatment with ligation of the internal spermatic vein may be needed, but the subsequent fertility is inversely related with the duration and the severity of injury to the testicular germ cells prior to the treatment