Endometrium: hypoplasia

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  • Cause : immaturity, gonadal dysgenesis, ovarian neoplasia.
  • Signs : failure of conception.
  • Diagnosis ; history, ultrasonography, endometrial biopsy and histopathology, chromosomal karyotyping.
  • Treatment : none.
  • Prognosis : good for immaturity; guarded for ovarian neoplasia; hopeless for gonadal dysgenesis.


Differential diagnosis

  • It is important to differentiate endometrial hypoplasia due to immaturity from seasonal endometrial atrophy that occurs during the winter when the mares ovaries are also small and inactive.
  • Seasonal atrophy can be recognized by a low cuboidal epithelium and straight glands that occur throughout the non-edematous lamina propria.
  • The gland lumen often contains inspissated secretion.
    If doubt still remains the biopsy    should be repeated during the natural breeding season
  • Biopsies procured from the posterior uterine body, an inch or two beyond the cervix, have few less well-developed endometriral glands (low gland frequency/density) that penetrate shallowly into the stratum compactum of the lamina propria.
  • Make sure that biopsy is procured further in the uterus to confurm true hypoplasia.
  • Taking samples from both uterine horns will confirm it is a widespread condition.
  • A pathologist should be careful about making a diagnosis before knowing the above.
  • Ovarian neoplasia    .


Clinical signs

  • Endometrial hypoplasia due to immaturity is usually associated with palpably small and inactive ovaries, with little or no follicular activity present on ultrasonography.
  • The remainder of the genital tract is normally developed for the age of the mare (filly).
  • Mares present with persistent anestrus    or irregular estrous cycles  [Female: prolonged diestrus]   [Female: shortened diestrus]  .
  • Mating is unproductive and is followed by a high incidence of persistent acute endometritis.
  • Gonadal dysgenesis    .



Expected response to treatment

  • Return to regular cyclic behavior and ovulation.
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