Testis & paratestis



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PubMed Search: Testicular biopsy [title]

Turki Al-Hussain, M.D.
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Cite this page: Al-Hussain T. Biopsy. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/testisbiopsy.html. Accessed March 21st, 2023.
Definition / general
  • Biopsy indicated for azoospermia (no sperm present) without endocrine abnormalities, since biopsies may show focal spermatogenesis
  • Most biopsies have 3 - 5 lobules plus septa of tunica albuginea
  • Usually see many spermatozoa, "perfect" tubules mixed with occasional tubules with scattered "disorganized" spermatogenesis
  • In young men, ratio of germ cells to Sertoli cells is usually 13:1
  • Multinucleated giant stromal cells are associated with testicular atrophy due to estrogens
  • Hyalinized tubules with elastic fibers indicate hyalinization developed postpuberty
  • Zenker's and Bouin's fixative are preferred, as formalin introduces significant artifact
Biopsy Results for Azoospermia (No Sperm Present, No Endocrine Abnormalities)
  1. Germ cell aplasia / Sertoli cell only syndrome (29%): tubular basement membrane thickening, no germ cells, usually normal number of Leydig cells
  2. Spermatocytic arrest (26%): usually early arrest at primary spermatocyte level (no spermatids, no spermatozoa), normal Leydig cells; may be late arrest (no spermatozoa only)
  3. Generalized fibrosis (18%)
  4. Normal (27%): usually associated with bilateral obstruction as seen in Young syndrome (also chronic sinopulmonary infections) or testicular blockage (50% of tubules lack lumina; disorderly maturation of germ cells); surgery (epididymovasotomy, vasovasotomy) is often successful

Azoospermia due to known obstruction:
  • Severity related to cause / span of obstruction, usually reduction in spermatids only due to increased hydrostatic pressure (47%)
  • Also can be normal testes (28%), reduction of primary spermatocytes and spermatids (9%), reduction in all germ cell types (13%) or hyalinization (2% [Am J Surg Pathol 1999;23:1546])
Biopsy Results for No Sperm Count Due to Endocrine Abnormalities (Testicular Failure)
  1. Hypogonadotrophic eunuchoidism (60%): low FSH and LH levels; small infantile tubules with few or no Leydig cells, scattered spermatogonia and Sertoli cells
  2. Klinefelter syndrome (30%): XXY karyotype, tubular fibrosis, prominent basement membrane thickening and Leydig cell hyperplasia; associated with increased incidence of breast carcinoma, possibly Leydig cell tumors, extragonadal (mainly mediastinal) germ cell tumors
  3. Testicular aplasia (10%): absence of testicular tissue, high urinary LH and FSH
Biopsy Results for Oligospermia
  1. Incomplete spermatocytic arrest: some tubules normal, some with arrest
  2. Regional or incomplete fibrosis
  3. Spermatogenic hypoplasia: tubules with reduced number of germ cells that are also disordered
  4. Tubular hyalinization: includes Kleinfelter syndrome (small diameter tubules with thickened basement membrane and increased Leydig cells)
  5. Mixed atrophy: synchronous occurrence of seminiferous tubules with germ cells and tubules with Sertoli cells only
  6. Normal spermatogenesis: associated with duct obstruction

  • Sloughing and disorganization: lumina contain desquamated immature cells, disordered spermatogenesis (nonspecific, can be seen in hypoplasia, duct obstruction or mechanical damage / artifact to specimen)
  • Other causes of oligospermia: varicocele, cystic fibrosis causing obstruction in epididymis and vas deferens
Fine Needle Aspiration (FNA)
  • Used to differentiate normal testis, hypospermatogenesis, early and late maturation arrest, Sertoli cell only patterns
  • Minimally invasive, may replace testis biopsy
  • 2 - 11 aspiration sites, 10 - 30 needle excursions / site; adequate if 100 clusters of 20 or more testis cells
  • May be more representative than biopsy since more sampling
  • Interpretation should focus on relative abundance of germ cells (primary spermatocytes, spermatids, mature sperm with tail) and Sertoli (support) cells
  • Frequency of clinical diagnoses: idiopathic nonobstructive (50%), varicocele (18%), genetic (8%), cryptorchidism (8%), cancer (8%), obstruction (7%), Kartageners syndrome (1%)
  • Hypospermatogenesis: presence but paucity of all germ cell types
  • Sertoli cell only: no primary spermatocytes, no spermatids, no spermatozoa
  • Early maturation arrest: primary spermatocytes but no spermatids, no spermatozoa
  • Late maturation arrest: all cells but spermatozoa
  • Note: FNA cannot assess basement membrane, which is important for neoplasm and CIS diagnoses
  • References: Am J Surg Pathol 2001;25:71
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